The Big “Beastly” Solar/Battery Upgrade Part II – Component Details
My last post talked about the WHY. Today we’re going to address the WHAT.
Basic RV Solar Components
Let’s start off with some very (very) “rough” basics. For those of you not familiar with RV solar systems there are basically 3 main components that go into your system:
-
The basics of Solar Power Generation (source: Alternative Energy News) Solar panels (= the magical panels that take the sun’s rays and convert them into electrical energy). Most RVers put these on their roofs, but some do keep them “mobile” and just put them out on the ground.
- Charge Controllers (= devices that take the “raw” power your panels produce and charge your house batteries). These connect between your panels & your batteries and do all the electrical stuff needed to make sure your batteries properly charge in the correct order/way they need to be charged.
- Batteries (= the storage devices for the energy you’ve produced). These are what your coach “sucks off” to power everything that runs on electricity inside it.
What happens in an RV solar system is that sun shines down onto your pretty solar panels, is converted (very inefficiently mind you) into nice, juicy electrical energy which is used to charge your house batteries. Then you, as the user, suck down those batteries however you’d like. There are other intricate details such as adding an inverter (if you want to power AC stuff in your coach) and how you tie everything together, but from a top-level point of view that’s really it! When you’re out “shopping” for your RV solar system you’ll be shopping for these 3 items.
LOTS of folks have written in waaaay more detail about subject so if you want to learn more, here’s a few nice links:
- AM Solar -> RV Solar Education Series
- Cheap RV Living -> Basics Of Solar Power
- Gone With The Wynns: How Off-Grid RV Solar Works
- Jack & Danielle Mayer: RV Electrical & Solar
- Road Less Traveled: Understanding the Basics of Boat & RV Solar Power
The “Perfect” System Size
When you’re living entirely off your solar system it’s really quite simple. Everyday you generate some power (= with your solar panels) and everyday you use some power (= draw from your batteries by using the electrical stuff in the coach). Ideally you want these two numbers to match (more-or-less) and ideally you want enough of everything that you can do what you want (electrically-speaking) without running out of juice.
But how MUCH that is, is a very individual thing.
Our “starter” solar system in 2010 had 440 amphours of AGM batteries (of which 50% or 220AH is usable) and 600 Watts of solar. For the BBSBU we chose 600AH of lithium batteries (of which 80% or 480AH is usable) and 1500 total Watts of solar. This will aaalmost triple our usable battery capacity (if you subtract phantom draw -> see table below) and more than double our solar generation capability. We have 5+ years of experience with our own use model so we knew this is exactly what we wanted and it was the perfect system size for us.
But YOUR numbers may be totally different!
All-electric coaches suck waaaaay more power (and thus need much more solar/battery) than little trailers. Folks who spend their days working on-line all day have higher power needs than folks who just go to the boonies to hang all day outside. Plus budget and space (how much you can fit into your coach & onto your roof) come into play too. In other words everyone’s energy needs are completely individual and there is NO one “perfect” system size. It’s just whatever size works for YOU.
Before you even think about installing solar on your own rig I highly recommend doing an energy audit to figure out your power needs. I won’t go through these details, but instead recommend checking out some of the following links:
- AM Solar: RV Solar Sizing By Actual Use
- Technomadia: Solar Planning: Conducting An RV Electrical Consumption Audit
- RV Solar Electric: Solar Design Worksheet
- Go Power: Size Your System Calculator
The “Perfect” Component Set
Just like the “perfect” system size, the “perfect” component set doesn’t exist. There are TONS of options for each of the 3 things I listed above (including even more “package” options) and as long as you buy decent quality stuff you’ll probably be fine.
There are specifics you want to look at as far as matching components properly (e.g. you want to be sure the solar charger you’re buying can handle the number of watts & the voltage specs of the solar panels you’re going to load onto it) and there are definitely specifics you want to look at when it comes to installing your components (I’ll go through some of these in my installation posts), but other than this there is really no “one” perfect set-up.
As an example, folks in a small trailer or on a budget might be perfectly fine with a few inexpensive solar panels (say, a few hundred watts?), a single inexpensive PWM solar charger and some inexpensive golf cart batteries. On the other hand folks in big rigs looking to push the limits of newer technology might want lithium batteries, multiple MPPT solar chargers and as many panels (2000 watts???) as they can fit on the roof. It’s all very individual.
If you want to understand more about the technical details of RV Solar components check our some of the following links:
- AltE Store: Solar Panels (Photovoltaic Panels) Overview
- Road Less Traveled: Solar Charge Controllers
- Technomadia: Understanding Solar Panel Specifications
- Handybob: The RV Battery Charging Puzzle
Our Component Choices
Below is the list of our “big 3” component choices and why we chose them. We did a ton of research and also talked through all these components many times with Marvin (our installer). It’s helpful to have a knowledgeable person to bounce ideas off when you’re deciding on stuff like this, and Marvin was awesome at fielding all our questions and guiding us along.
With that said here is our new “perfect” solution 🙂
600AH Elite Power Solution (GBS) Lithium** Batteries
In the Lithium world there are a few, select guys who make the “battery cells” (= the individual “lego block” pieces that go into the battery pack) and a few more guys who put them together to make assembled battery packs. Also since Lithium batteries charge differently than lead-acid and are very sensitive to over-charging & over-draining, you want to add systems that accurately monitor the state and health of your individual cells & your pack. This extra equipment makes Lithium more complicated than regular lead acid batteries both to install & monitor, but it’s important stuff IMHO.
In our case we went with Elite Power Solutions and bought three of the GBS-LFMP200AH battery packs (total 600AH). The cells in our batteries are made by a company called GB Systems (= the blue-colored cells, if you ever see them), while Elite Power Solutions (EPS) are the guys who put them together into an assembled pack. In addition to the packs themselves we bought the EMS 4-cell String Sense Boards, the EMS CPU (basically the computer for the energy management system) and an EMS LCD Screeen so we can monitor and see everything that goes on with our batteries.
We chose the Elite packs rather than other guys for 3 main reasons :
- Experience Of Use -> EPS are the the most-used packs in RV/boat installations and the ones you’ll see most discussed on all the RV & boating forums. Several of our personal friends use them so there’s lots of experience out there and we have many folks we can rely on if we run into questions etc. There’s a certain comfort that comes with using something that other people are using.
- Good Battery Management Systems -> The EPS packs pair very nicely with the EPS cell balancing boards and and management system. It’s just a nice, complete system. We like that we can monitor both the health of the individual cells themselves as well as the overall pack.
- Good Support -> Elite are known for their good customer service & support. Marvin (our installer) has personal experience of this from his multiple years of working with them, plus we have friends who’ve confirmed the same. We place high value on good support.
This trifecta of stuff made them the easy choice for us.
What Else We Considered -> We DID look at Balqon mostly because of price (they typically offer the best lithium prices on the market), but after 4 months of trying to get a hold of them and never getting a single call back we gave up. We didn’t really consider other manufacturers.
**NOTE/ If you want to know WHY we chose Lithium (as opposed to Lead Acid batteries), feel free to click back and read PART I of the BBSBU series.
900 Watts of GS-100 Solar Panels
We decided to keep our original 600 Watts of RV100 (no longer made) solar panels. They’re still great panels, they’re a nice, compact size and they still work perfectly so we wanted to preserve that initial investment.
For our upgrade we decided to ADD 9 of the GS100 solar panels (100 Watts each) sourced from AM Solar. They are NOT the cheapest panels out there, but they’re super efficient (= how efficiently they convert sun to electricity) so they pack that 100 Watts into a really nice, compact space.
Their biggest benefit IMHO is their super-narrow format (they’re only 20.7″ wide) which means we can fit lots of panels on the roof with zero shading from any of our roof objects (vents, air-conditioners etc.). Since shading/shadows are one of the biggest KILLERS of RV solar installations (seriously, a mere 5% shade can crash your output!!) this was the MAIN reason we chose them.
The two sets of panels combined will give us a total of 1500 Watts of solar panels on our roof.
What Else We Considered -> We didn’t consider much else since we were already sold on the narrow GS100 format, but there are tons of other options out there. If you’re using the panels on the ground, you can chose just about any panel you care to carry around. If you’re using panels on your RV roof, it just depends what you can fit on your roof (without shading!!). For the more budget-conscious AM solar offer a slightly bigger SF100 panel (100 Watt), while Renology offers a similarly-sized 100 Watt Panel
What About Flexible Panels? Flexible panels are all the rage right now, and for many smaller RV’s or RV’s with weird-shaped roofs they are very compelling since you can just stick ’em on and be done with it. However, we’re honestly not fans. We have friends w/ flexible panels who’ve seen them deteriorate far too quickly for our comfort, and over fairly short periods of time too. We’ve seen cupping issues (the cells deform into “cups”), over-heating issues (since they’re stuck right onto the roof and have no air-flow under them, this is a common problem) and far-too-easy scratching all of which deteriorate their output. Flexible panels are definitely getting better (all the time), but IMHO they’re just not there yet and I’ve yet to see a flexible panel that has “stood up” to long-term RV abuse. On the other hand hard panels have been around forever and are a solid technology. They are waaaaay cheaper, typically come with 10+ year warranties and our experience of 5+ years confirms they can handle serious abuse.
Four Blue Sky 3024iL Charge Controllers
Our charge controller decision was probably one of the most difficult (and most discussed) decisions we made. There are LOTS of great chargers out there and they honestly all do a pretty decent job. In our case we decided to ditch our old Morningstar MPPT-45
Each of our Blue Sky controllers is rated to handle up to 40 amps & 540 Watts. So we needed 2 controllers for our 600 Watts of old panels & 2 for our 900 Watts of new panels, for a grand total of 4 controllers.
The main reasons we chose this set-up are partly technical and partly geekish:
- 2 Different Panels/3 Different “Solar Systems”-> We wanted to keep our 6 old 24V panels while adding 9 new slightly lower-voltage panels. Plus we decided (partially for geek reasons) to install our new panels in 3 separate roof configurations (I’ll talk more about this in our installation posts). A modular controller approach was the only way to make this happen.
- Networkability & Central Control -> We wanted all our controllers to “talk” to each other but we also wanted a single, programmable system that controlled them all.
- On The Fly Programmability -> In addition to networkability we wanted to be able to program our controllers “on the fly”. This was (especially) a requirement for our new Lithuim system since we wanted to be able to mess around with parameters, including absorption time, charging voltages and other details.
- Access To Data -> For our “geek” experiments we wanted to have the ability to look at the data log history of both the overall system as well as each controller individually, and we wanted to be able to do this directly from our computers without having to plug into the controllers one-by-one.
Switching to multiple, compact Blue Sky controllers (and adding the Remote & UCM module) allowed us to do ALL of these things -> we will have 3 different “solar systems” running on 4 controllers. The controllers can be individually programmed, but will also seamlessly network together to act as “one”. Plus we can program them as we want, whenever we want and delve into the details of how they’re doing on our computers.
What Else We Considered -> We looked at Morningstar, mostly because we already had one controller and could have expanded our system by adding two more Morningstar MPPT-60
Coming Up Next -> BBSBU Installation Posts!
Are you going to sell your Morningstar controller?
Most definitely. It’s still a great controller & working perfectly. We have the remote panel too. Interested?
Nina
Yes.
Awesome info. Thank you!
I do so love this geeky stuff!
1200 watts wow! Way cool. I agree with you about Balqon—I would not buy from them again, due to their very poor customer relations. Did you have to pay Arizona sales tax on your GBS batteries? In AZ, all solar installation components—including batteries—are supposed to be sales tax exempt. I last contacted EPS directly about this in 2012, and they were surprisingly unable/unwilling to make that reasonable accommodation on their LiFePO4 cells. Which are amazingly the exact same high $560/kWh they were four years ago on those 200Ah’s!
Are your batteries going to be in a temperature controlled environment? Will you have a way to monitor the battery temperatures?
Any active cooling or heating planned?
LFP batteries do not need temperature compensation, but you can’t charge them when they are below 32 degrees or they will be damaged. That means it is best to have the batteries in an enclosed bay, so they will stay warm. Our LFP batteries are not that protected from the outside, but I suspect Nina and Paul’s will be. I have had to cover them with a blanket and use a terrarium heater in freezing weather.
Also notice the Elite Battery Management System display shows temperatures.
Yup, yup and yup. Like Bill mentioned temp control is mostly to prevent batteries becoming too hot (in summer) and prevent them becoming too cold (in winter…they can’t charge if they get too cold). I’ll be writing details on all this in my installation posts.
Nina
Great job as always, very informative!
Here’s a question if you already have Solar and have written it off, I believe its 30%, when you upgrade your system do you get to write that off again with the feds?
Yes, you can. My understanding is that you get to claim again as long as at lest one solar panel is added to the job. See here:
http://www.wholesalesolar.com/solar-information/federal-tax-credit
Nina
Excellent post.
Too geeky for me but if Nina and Paul are happy–that’s good!!
Just put a remote thermometer ($20 or so from any hardware store) in the battery bay and monitor the temperature. We use the front bay of our 5th wheel for the LFP battery suite so they are well shaded. We leave the front panel up as well as one of the side panels open for cross breeze. We plan to put in two 12 V recepticles to run 12 V fans (12 W) to increase air flow over the batteries. A worry is low tempeature (below freezing) for battery charging. Several 12 V (30 W) bulbs keep the temperature above the mid 30s at ambient temperatures below 20 F. The inverter can get warm when running the air conditioning off battery/solar panels combination
Yup, we’re going to put in a few 12V fans (Marv recommended this too). Right now we’re monitoring temps closely. We have the batteries installed *inside* the rig in a very well-controlled spot (I’ll be talking more about this in my installations posts), but we also have the inverter in the same area and I think we’ll add some fans just for extra flow when we need it. It shouldn’t EVER get that cold where we put them (if it does, we’ve seriously erred in our travel plans), but we can easily add heat too as needed. Temp control is definitely a factor for Lithium and something that makes their installation needs different from lead acid.
Nina
Looks lovely, and so much power! Very envious, but your Beast is bigger than our Bella, so we can’t fit as many panels on the roof (when we get it!). So it won’t be us that overtakes you on this one 😉
Your new controllers are so teeny compared to the MPPT! Peter drooled over them but decided we will stick with our MPPT as it can handle our panels on its own (vs needing 2 like yours), so it will be interesting to compare notes on how the MPPT performs compared to your controller set up once ours is all up and running.
Looking forward to the next installment! Always love reading your posts, even if I don’t always make a comment. Loved all your talks from the storage unit by the way, resonated so much as we were on the final leg of emptying the house and selling everything while you were emptying your storage unit. I don’t EVER want to do that again !
Our controller testing is definitely going to be interesting! This is the first time we’re going with a modular multi-controller set up and I’m very curious to see how they perform. Marv really likes the Blue Sky (they had this controller and several others set-up for display at AM Solar while he was there last summer, and he said Blue Sky was always one of the first to crank and showed some of the nicest boosting), but it’ll be interesting to see first hand.
Nina
Great post Nina and Paul. Bristling with great info.
We’re still waffling about solar, mostly about whether we’d use it enough to justify the cost. As always your posts answer a lot of our questions about specifics and thank you again for taking the time to put all this together.
It’s a big investment, no doubt and it’s always tough to know for sure how much you’ll use it. When we installed our first system at the end of 2010 we were pretty sure we’d like it (we’d been traveling on our generator and dry-camping a lot that first year), but we didn’t know that we were going to LOVE it quite as much as we have.
I think that if you have a generator and are not sure how much you might dry-camp/boondock, it’s good practice to just travel with that for a while to see how your lifestyle pans out.
Nina
Terrific Information, thanks for all the work you have put into this and good luck with the new system, sounds fabulous.
Ah….now I understand. by the way, I enjoyed Paul’s fish imitation….
LOL…yeah the “oooooo” look turned into more of a fish look on that Lithium selfie. Geek pics 🙂
Nina
would love to see a picture of all the solar panels on the roof, I can’t image 9 plus what you had before…
It’s coming, definitely coming….
Nina
Great job of explaining where you were coming from, and thus trying to preserve, existing investments respected solar panels from Install #1. Added complexity and a few more controllers to do this, but also provides more flexibility in usage.
You also did a good job of explaining that ‘one size may not fit all’. Smaller say Class B’s or C’s just do not have the roof real estate for larger panels. And you nailed the decision process new system dreamers should consider to reduce shading. Your Install #1, and all but one (and maybe 4-6 other boating related) links on solar are what we went thru about 3 1/2 years ago as we planned our system. Mostly due to shading concerns, I elected go with the larger panel approach, using convention S&B roof top solar racking system. We have 4 panels spanning our bathroom skylight, and a 5th mounted directly to the roof. (X’s 5 Panasonic 240S, also high efficiency.) I elected to abandoned two 110W larger panels, and frankly the were not of very good quality and or efficiency, that the first owner had installed. (A friend has these on his work cargo van now, along with the controller, keeping a pair of GC2 6V’s charged.) So that allowed a clean slate.
Really looking forward to see how you mount the 9 new panels in your install edition:)!
And for those who might want to consider Big Panels, I can confirm that the LG315’s are kick arse panels. We have 24 just installed and up in running on our vacation home. Even now this time of year, we’re seeing 40-42 kWh days. Looking forward to what peak June will generate. And note, LG has the LG330 version of this same panel, about to be available.
As always, thanks for the great write up. Do you have any friends that have children you want to bring into this thread to sale Girl Scout cookies – worked well for Chris’s kids troop last night:)! You have almost as big as followers… And heck with delivery, they can limit sales to Operation Thin Mint!!!
Best,
Smitty
Cheers for chiming in on your experience, especially with the bigger panels.
We have good buddies of ours who are installing the LG315’s on a their 42-foot RV and they have a big roof-rack just like you so they can basically just plaster their entire roof with panels (without shadowing). I can’t remember how many Watts he’s going to end up with, but it’s pretty epic.
Nina
In future posts could you add weight. For those of us with towing RV and need to be careful of weight.
Love the blog!
Alison
You certainly want to be sure you don’t go over the weight carrying limits of your RV (with anything that you add to it). In our case “the beast” will be about the same weight after we finish the BBSBU, thanks mostly to the massive savings in weight we’re getting going from Lead Acid to Lithium.
Here’s the specific numbers for us:
1/ Batteries -> Our old 440 AH Lead Acid that we had in our bay weighed 264lbs. Our new 600AH of Lithium weighs 165lbs (55lbs for each pack). Weight savings = -99 lbs
2/ Battery Compartment –> Since we got rid of our Lead Acid & didn’t need our huge, heavy sliding metal battery tray anymore, we got rid of it. Weight savings = -50lbs
3/ Solar Panels -> We had 6 panels up there already. We’re adding 9 of the GS100 at 14.5lbs each. Weight gain = +130.5 lbs
TOTAL = -18lbs (savings)
That’s a rough estimate and doesn’t include all the smaller pieces, but it’ll end up being wash all in all. We’ve also redistributed the overall weight of the RV just a bit by lightening up a tad on the back right axle (where the old batteries were) and adding a tad to the front axle (where the new solar panels are going). Our rig has always been a tad too heavy on the back (a typical problem w/ our model), so this should actually help our overall numbers. At some point we’ll get the rig re-weighed on all 4-corners to see exactly how everything has changed, but I expect we’ll be right on mark with where we were before.
Nina
Thanks for the updates. Very interesting and educational.
What a nice system as it’s been exposed so far! The perfect blend of proven new tech (lithium) with a splash of forward leaning pioneering (your networked charge controllers) all wrapped in a cool, geeky, “mine is bigger than yours” (today) style. Your writing is both entertaining and informative. I look forward to each installment more and more.
Have you considered that the Beast might become the Millennium Falcon if it gets much cooler?
Seriously, I’m taking notes like mad towards my own future system.
LOL…thanks. We may have to add some laser turrets & a hyperdrive after this done, just to upgrade our cool factor 🙂
Nina
Nina, I am confused as to why you would need a heated bay. Here is the spec listed on the website for the batteries.
Operating Temperature: -20 to 65 C or -4 to 149 F
They are not listing restrictions besides the above number. Do you know what is up with this?
Thanks, Randy
Those are indeed the listed operating parameters (cells can still be used), but not the correct charging parameters. Lithium can’t be recharged below 0C or 32F without suffering some permanent damage, and that’s a well-known Lithium limitation.
I honestly don’t know why this isn’t listed directly on the EPS battery specs (it really should be clearly marked), but if you look at the EPS Power management system manual (page 17) you’ll see it has default alarms set when the min cell temp is under 32:
http://elitepowersolutions.com/docs/EMS%20Operation%20Manual.pdf
Also you can read more about lithium charging specs here:
http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures
EDIT UPDATE/ You an also see the charging spec limits in the EPS FAQ section:
“Proper operating temperature ranges are -20 to 65C for discharging and 0 to 65C for charging”
http://elitepowersolutions.com/faq.html#q4
Nina
How exciting! Congratulations and thanks for the post Nina. As always, excellent information explained most clearly. My new airstream is going in for her solar system in a couple of weeks. I had such a hard time figuring out what I needed from all the solar posts out there – information overload. You’ve summed it up brilliantly. I will have the same basic components, minus the lithium batteries, and on a much smaller scale! I still had long conversations with myself over the expense, but in the end definitely believe it will be worth it.
I think you’re going to love it! It takes time to sort through all the possibilities out there, and it’s ALWAYS possible to get a bigger system (I know folks with even bigger systems that our BBSBU!), but you’ve just got to work with what makes most sense for you. ENJOY!
Nina
Interesting. You’re going to love the BS controllers you selected. I ran with one 3024iL & 420w on my old coach for years and loved its reliability/configurability. And Elite’s lithiums have performed flawlessly on my SLA converted scooter for several years 🙂 Had I not found Magnum’s PT100 (http://www.magnum-dimensions.com/pt-100-mppt-charge-controller) to work with my already installed MS2812 – that’s the way I’d have gone too. It’ll be fun to compare our systems side-by-side someday!
Can confirm Elite cells don’t like charging when it’s hot (100+/- degrees or more). The big red Overtemp light comes on and they won’t charge. In the summer (Phoenix), I have to bring the scoot inside for air conditioning to accept a charge.
Interesting. I know heat impacts Lithium lifespan (and can de-rate their capacity over time), but didn’t realize it impacts charging too? I’ll have to look at that portion bit more. We had fun messing around with the hybrid inverter functions today -> I love that we can tweak the load support function all the way down to 5 amps.
Yeah…it would be fun to compare systems one day 🙂
Nina
Wow, 1500 watts of panels. Our house has 3300 watts! You’ll really be in great shape. Our batts are still rather young but we’re looking forward to reviews on the Tesla Powerwall for the future.
Pat
There are definitely more Lithium options coming on the market for residential (many of which won’t be suitable for RVs), so it’s exciting stuff. The trend has started and will only improve. I’m still hoping Tesla will make an RV, but I’m not holding my breath 🙂
Nina
I’ve been reading some RV blogs for a while now since 2015. I am hoping that my wife and I are healthy enough to go full time RVing when she retires and she chooses this retirement option. I am wondering once I calculate out our electrical power needs if I should have some type of multiplier for our solar system since on rainy days I would want to use the computer more or even watch TV. So what should my multiplier be?
So, that’s a bit of a tough question. On rainy days you’ll be producing very little solar (you’ll likely be down to only 10-20% of rated panel capacity), so that’s when you actually need more battery capacity since you’ll be living almost exclusively off your batteries at that point.
If you want to be able to last without turning on your generator (which you can always do, of course) you’ll need to multiply up your daily amphour usage on the battery side. So, for example if you typically use 110-150 amphours per day you’ll want to have 2-3 times that number (of *usable* battery capacity) to cover 2-4 days of heavy rain or clouds. It’s not exact since, like I said, you’ll still be producing *some* solar, but that’s kind of the gist of it.
Nina
Well, you certainly have impressed me. As usual, your wordsmithing is the best. You are going to have a state-of-the art system.
Like you mentioned, one size does not fit all. Everyone has to decide what works for them. Although ours is more along the lines of the system you are leaving behind at 440ah of deep cycle wet cell and 400 watts on the roof, we designed ours for expansion. I can get at least another 400 watts up there using the same panels and dimensions we are using presently…Renogy 100 watters with a 21″ width. Similar dimensions to yours. Hard to find. We chose the Morningstar MPPT-60 charge controller at inception to handle the future expansion. Time will tell.
In the meantime, you will rightfully be crowned the King and Queen of Geeky Solar RVdom. No wait, this just in…Taylor Swift’s tour bus has 2000 watts and 800 ah of Lithium. 🙂
You chose wisely with the MPPT-60. It’s nice to have the option of just adding in more panels to your existing system. And those 21-inch wide Renology are a very nice format. We always kind of wish we’d chosen the bigger controller in our old system (for expansion purposes), but we were maxed out at 600 watts on the MPPT-45 so we couldn’t go any bigger on that one. Of course now we’re fully modular, so if we (for whatever crazy reason) decide to go bigger in the future we can just tag on another Blue Sky to our existing network.
Nina
Chris of Technomadia did an excellent writeup of problems encountered as the absolute pioneer (along with Dr. Jones) of LFP for RV’ing. His LFP suite was in the same bay as the inverter. The inverter can, as noted in post above, get fairly warm when used to run the A/C and this heats the battery suite. Their bay was closed and had no cross-ventilation, the bay was sun-loaded in Phoenix and they were on tarmac at an RV shop I believe. The fans you plan to put in should help cross ventilation. We have half a dozen 12 V recepticles (aka cigarette lighters) about the 5th wheel for charging various devices and running 12 V (10 W) fans. Such fans make a real difference when boondocking and the sun is down and A/C is not something to run past getting the cabin below 90F.
There’s definitely some heat that comes out of the inverter when running heavy loads, but the rest of the time it runs pretty cool. I think the bigger problem w/ installing LFP in a bay is the heat of the bay itself. Blacktop radiation on the bottom of the RV combined with heating of the bay metal (with no ventilation) means it can get very, very hot in there just from sun effects. We have a thermometer in one of our external bays (something we’ve had for years) and we regularly see 20-degrees hotter in the bay (compared to inside the RV) on warm days.
Nina
Thanks for the prompt reply back. I like to plan things out. We had a bad experience with our 1990 or so Starmaster Vista pop up camper (sold it in 2014) with the RV dealership that we bought it from (more than a handful of complaints). We had better service with out of state RV dealerships while on vacation. So looking for how to do things online before making any new RV commitment.
Paul and Nina,
What a great list of efficient and useful solar power system components. RVers new to solar system will be able to learn so much from your postings. As a matter of fact, we should give big thanks to you because of your posting of the Magnum Hybrid Inverter sold by iMarine at deep discount price. We bought it as soon as we saw your posting and saved $$$!
We also agreed with your assessment on the flexible solar panels in the last post. We bought a 60W flexible panel along with a rigid 100W mono-crystalline panel to set up a solar system in our toad to charge PCs and cameras. The 60W flexible panel deteriorated quickly within one year of usage while the rigid panel has stayed in good shape.
We enjoyed reading your postings as always!
Great feedback on the flexible versus rigid debate. Sadly I’ve seen exactly that with most of the folks I know who have both. I think flexible are getting better, but they’re just not there yet.
Cheers for sharing your experience!
Nina
I hear you on not getting replies back since I had emailed a RV manufacturer and never heard anything back from their state sales rep in one week.
I finally calculated out my amp hours. I calculated it out to be roughly 1,200 amp hours based on one of your links above, but that included running the refrigerator 24/7 on solar power and an additional 4 hours per day for air conditioning. So if I ran the refrigerator on propane my needs would be 361 amp hours. So what am I looking at solar watt panels wise both ways?
I looked at the wrong column. The air conditioner was for 8 hours.
Air conditioner is a BIG draw, as are electric fridges (although not quite as much as air). You can change your draw significantly by having a fridge that can run on propane (when off-grid) and limiting air conditioning.
If your needs are around 360 amphours per day, on battery side you’ll need at least twice that if you’re using lead acid (around 720 total amphours lead acid) or at least 1.25 times that in Lithium (around 450 total amphours). Also if you’re serious about air conditioning you’d want to stick with lithium since they can handle the big draw much, much better than lead acid. That quantity would *just* satisfy your daily needs. You’d want more batteries if your goal was to last more than one day on batteries alone (a typical target is to have 2 days worth of battery capacity).
On the panel side, using the example from the AM Solar website = “a typical 100 watt solar panel produces an average of about 6 amps per peak sun hour, or about 30 amp-hours per day”. So your 360 amphour daily needs corresponds to around 12 panels (= total ~1200 watts). Again, this would *just* cover your daily needs. You’d want more if you get extra batteries, or to cover semi-cloudy days etc.
Nina
I just found this refrigerator link (2118 Polarmax):
http://www.thetford.com/product/2118-polarmax/
It does sound heavy for the carrying weight, but is a ton more efficient than the refrigerator electrical needs in the link that I used in calculating out my energy needs. One of the benefits on the refrigerator is that the LP kicks in if there isn’t enough electric power. So what do you think of this refrigerator?
Looks like a nice fridge. Don’t have any personal experience with that brand so I can’t say much more, but I do like fridges (in general) that can do both propane and electric. It saves a ton of energy draw while boondocking. Our fridge is a Dometic propane/electric and we run it exclusively off propane while we are off-grid.
Nina
I was trying to save on propane by putting the refrigerator and the furnace on the solar panel electrical system. I now see that it was an impractical idea. I changed some of the other numbers as well. So my new numbers are 94.83 amp hours with no air conditioning and 154.43 amp hours with 4 hours of air conditioning per day. So I decided to compare a couple of solar power systems, which would allow me to do the air conditioning at least sometimes off the grid.
2 200 amp hour lithium battery packs = $2,960.00
10 AM Solar GS 100 solar panels = $2,799.90
2 Blue Sky 40 amps/540 watts charge controllers = 754.86
TOTAL = $6,514.76
Area taken up by solar panels = 8,445.6 square inches
Produces 300 amp hours in a day
For no air conditioning = 3.18 days, with air conditioning = 1.94 days
Weight for 10 AM Solar solar panels = 145.0 pounds
2 200 amp hour lithium battery packs = $2,960.00
6 Grape Solar 160 watts solar panels = $1,379.94
2 Blue Sky 40 amps/540 watts charge controllers = 754.86
TOTAL = $5,094.80
Area taken up by solar panels = 9,048.0 square inches
Produces 288 amp hours in a day
For no air conditioning = 3.04 days, with air conditioning = 1.86 days
Weight for 6 Grape Solar solar panels = 158.4 pounds
On the other gadgets that Nina mentioned the prices would be the same for both systems. So I am going to ask a question. Are 12 amp hours taking up 602.4 less square inches worth $1,419.96? The Grape Solar system suggestion is slightly heavier. With the 4 hours air conditioning neither system produces a full two days of electrical power, but close.
Nina can correct if I am wrong, but a weakness of going with the LG Neon 2 315 W Solar Panel systems is that for every solar panel bought, it would require its own charge controller.
So Nina does my numbers add up this time? What do you think of my solar power system suggestions?
I have to admit that I’m no expert on solar system design, and haven’t done all the calculations for this list, but here’s a few passing thoughts:
1/ On RVs solar panel choice is not just about cost, but also placement. Can you fit all those 160W panels on your roof with NO shading (from roof vents, air cons etc.)? If you can’t you are probably better off getting the narrower panels IMHO. Shading is a killer (just 5% shade can crash your output) so a smaller system with no shade will typically outperform a larger system with shade. Don’t underestimate the shade problem.
2/ For the LG panels you’d have to build a roof rack (no way to install panels that big on an RV roof without shading otherwise). On charge controller side for that system you will probably want to look at a larger Midnight, Victron or Outback. They’re made for residential systems with large, high voltage panels which exactly is what the LG are. I don’t know the specs off-hand (how many watts, and what voltages their chargers can handle) so you’d have to look that up.
Nina
It just seemed to me with a RV being 8 feet wide and only 30 feet long added up to 34,560 square inches on the roof without accounting for your air con, roof vents, etc. Before taking into consideration those air con, roof vents, etc. shading problems the Grape Solar proposed system is only 26.2% of the roof. So I thought that it would be possible to get on a Grape Solar system for less money. When I did my analysis the AM Solar panels that you suggested are almost twice as expensive as the Grape Solar panels per watt. You don’t get twice as much efficiently – .118 watts per square inch vs. .106 watts per square inch for the Grape Solar panels. The AM Solar panels would take up 24.4% of the roof area. So the AM Solar panels would take up just 1.8% less of the roof in my RV example of 8 feet wide and 30 feet long. So does shade and obstacles really take up almost 70%+ of the roof? So where would you go to get information like this before you purchased a RV with all those shading details? I am no expert either and just trying to learn things.
It’s actually much simpler than this. It’s not so much about total roof area, but about how/where your shadows move on your roof during the day and whether you need a narrower panel to avoid those shadows. The “laymans” way to do figure this out is to create cardboard cut-outs for the size of panels you’re considering, place them on your roof & see how your roof shadows progress throughout the day. Are they passing over the cardboard cut-outs? Or missing them?
There are lots of cheaper options than the GS100’s (e.g the Renology 100 watt I mentioned above) with only slightly wider width’s if you decide you need a narrower format, but just don’t want to dish out the extra $$ for the GS100’s. The 160 watt panels are a more significant jump in width so it just depends on your roof configuration & what kind of space you have up there. And yeah, you’d be surprised how big of a shadow an air conditioner or an antenna (for example) can cast on a roof. If you want to read more about shading effects have a look at this detailed write-up from a fellow blogger:
http://www.livesmallridefree.com/blog/solar-panel-shading-experiment
It’s hard to do all this before you buy an RV since every RV has a different configuration of “stuff” on the roof.
Nina
BTW thanks for all the replies. I am learning a lot. I just wanted to be close to the merchandise budget that I formed. Even the Grape Solar panel system would be roughly $2,000 or so over the solar panel budget that I had. So that would make the AM Solar panel system above around $3,400 over budget. I guess that I could do without the vent free propane heater and use our goose down sleeping bags on cold nights. So I have more budget cutting to do.
Ralph, read the below and then tell us again how much you’re planning to spend? With what you save, you might just be able to buy a new Samsung RF18 refer, which is awesome! 😉
Shading, Old vs New – it used to be that if you shaded even one cell on a panel & that panel was wired in a series string with other panels, the shading would bring down the output of the entire string by a huge amount. Newer panels are divided up into 3-5 sections that each have bypasses built-in. If this type of panel is shaded, only the sections with shading are affected because the bypasses for those sections are activated. The rest of the string then produces full power reduced only by the amount that would have been put out by the sections which are shaded. While still important, bypass capability makes partial panel shading less of a concern.
Large vs Small – Larger new house panels are also far more economical than smaller ones if you have the real estate up top. I’m installing 5 grade B Suniva 60-cell OPT285’s east-west grouped 4 & 1 separated by the low profile rear AC. Cost? –> 5 panels – $194 ea or $974 total for 1,425 watts. These panels will be mounted 12″ in from the rounded roof sides. If I didn’t care about aesthetics from the ground or weight I could go with larger 330 watt 72-cell grade C Suniva panels (for $149 ea). However, those would have to be mounted only 6″ in from the rounded edges of the roof sides and they weigh 12 lbs more, each (60 lbs total more). I’ll likely use the same mounting hardware as Nina & Paul. However, the middle 4 panels could also be mounted using a single Unirac mount with 3-4″ risers ( due to the crown in the roof). Unfortunately, that would add about $500 to the cost and some weight too. A benefit of east-west mounting relatively close to the roof sides means I’ll be able to raise/lower the panel tilt from the sides (either direction) of the coach without climbing onto the roof. And should I choose the Unirac mount for the center 4 panels, I’ll be able to do that with just 3 supports for the middle group and 2 for the one on the rear (5 total). I went with a single Magnum PT100 solar charge controller found online for $719 and that perfectly mates with my Magnum MS2812. Calculations show it can handle all 5 panels wired in series down to -20C! If I had more real estate it could handle over 6,000 watts using combiner boxes mentioned by Nina! Something makes me think with only 1,400 watts it will be loafing on my system. 😉
Nina & Paul wanted to reuse their old panels so opted for the Blue Sky route. I’m starting “fresh”, have the real estate up-top and wanted an all Magnum power management system. I really like Nina & Paul’s closet mounted Elite lithium setup and will be making a trip to Chandler AZ next week to discuss options for our closet. Thankfully, we keep our underwear elsewhere! 😉
PS – I’m also considering a linear actuator to lift/lower the center 4 panel set but finding it hard to justify the extra weight and cost. If anyone has a design for this kind of thing please speak up!
I agree that bypass diodes have improved the whole shading problem over the years. With “old” panels a bit of shade could shut-down your entire solar panel (and completely “kill” the string, if your panels were hooked-up in series). These days you can shade a part of the panel and still get *some* output. But it’s still a pretty serious crash in output nonetheless, and I feel that avoiding shade is still hugely important. I really recommend reading the shading write-up that I linked to above. These guys tested shading on their panels (with by-pass diodes) and plotted exactly how much fall-off they really got. It’s eye-opening stuff: Live Small & Ride Free: Solar Panel Shading Experiment
As for actuators, we’ve never done it but one of my blog readers implemented a system years ago and gave me some pics of it. You can see the pics & details in the comments on this post (see about half way down the comments section):
RV Solar Part IV – Panel Tilting & Winter Solar Optimization
Nina
Van, I saw your comment above – “I went with a single Magnum PT100 solar charge controller found online for $719 and that perfectly mates with my Magnum MS2812. Calculations show it can handle all 5 panels wired in series down to -20C! If I had more real estate it could handle over 6,000 watts using combiner boxes mentioned by Nina! Something makes me think with only 1,400 watts it will be loafing on my system.”
That output is relevant only to 48V battery systems, as the PT-100 has a 100 amp limit and so will only output 1200W into a 12V system. As I have an extensive Magnum network on my coach already, I want to us eat ePT-100 as well, but will need two of them to drive the 1800W panels into my 12V battery, but the ME-ARC50 meter only supports a single PT-100. I have a question out to Magnum Tech support to see what options I have to run greater than 120W PV into my Magnum network, using their meter(s) to control the system. Barry
I am wondering if Nina can answer some more questions for me after seeing her new Solar System on top of her RV roof. Exactly what percentage of your RV roof is taken up by your solar panels (all 15 of them)?
I knew back in 1991 not to put the DirecTV satellite system on top of the roof (met some nice people back then and chatted a short time). People confirmed this to me around 2001 on 5 week vacation.
Based on my 8 feet by 30 feet RV example without counting the obstacles and shadows and I could place 18 solar panels on there and only wanted to purchase 6 initially.
Haven’t done the calculations, but you can see the approx. coverage from the drone pics in my Part III blog. We also used to have a DirectTV satellite dome on the very front of our roof (you’re smart for not getting one), and removed that just prior to this install. That gives us space for 4 more panels if we chose (in the future). Prob won’t do this anytime soon, but we have the space if we want it.
Nina
Ok, how wide is your RV as I read that it is suppose to be 40 feet long? If I had my way, I wouldn’t have the DirecTV as I could get all my info that I need off the internet, but the wife would like to have it (probably take our house one off the roof and see if we could use it while RVing.
Our RV is standard 102 inches wide.
By the way if you want satellite TV I highly recommend getting a portable dish rather than a fixed one on the roof. Sooo much more versatile, especially when you’re parked in places with trees and no direct line of sight to the southern sky (which happens way more often than you think). We sure wish we’d gone that route back when we had Direct TV.
Nina
I read online that I think that it was Sony that produces a 700AH battery and will be increasing it to 1000AH by 2020. I am not certain that this will be RV use, but the application should spill over hopefully.
http://www.extremetech.com/electronics/219729-sony-plans-to-boost-battery-performance-40-percent-by-2020
The phantom draw of 30W seems quite high. Did you try to pinpoint it?
Great write up you two.
We have lithiums in our Class B, AGM’s in our boat and flooded cells in our off-grid home. We have watched the technology evolve and are starting to get to a point where we will need a new 24v battery bank in our home. One thing we are finding though is that there is a real lack of controller manufacturers that are making true lithium solar controllers or at least have a proper setting/algorithm for lithiums. Running a controller, set to AGM’s, is a compromise – it seems. Do the Blue Sky’s have a lithium setting now?
Regards,
There’s no specific Lithium setting in the Blue Sky, but they’re completely custom programmable. So you can basically program any setting you want. Plus they’re programmable “on the fly” from the remote so you can easily change the settings as needed. We’ve used custom program settings since we got them.
Nina
Ah, good to know! Thanks Nina.
Regards.
Nina,
Feel free to put my last two posts on this solar power link. No hard feeling here. I am used to the high school football forums whereby things get bumped up by the last reply, but on this and other blogs it doesn’t work that way. So I will try to keep it on topic from now on.
I do have another question on the solar power set up so I can understand why you did it the way that you decided to add more solar panels and equipment. The 450 amp hours from the solar panels are pretty close to what you are getting daily. On the BBSBU Part 2 it is stated that the lithium batteries are 600 amp hours with 480 of that usable and only 420 amp hours if counting phantom draws. This means that the battery can get almost fully charged up every day unless you get down below 150 amp hours (really 30 of usable left) left in the batteries. I can imagine that you are using 105 – 140 amp hours per day based on your 3 – 4 days worth of batteries in case it rains that long reply to one of my posts. It just seems to me that you are producing a lot of energy for very little battery consumption. In more than one book that I read said to unplug electrical items until you need to use them to save on the phantom draw.
Why do people need an antenna on the RV roof if they have a portable DirecTV system? I have lived in one location for 30+ years and never had an antenna for either cable or DirecTV. We haven’t had an antenna other than the TV rabbit ears even before we got the cable system (got cable first, then DirecTV later). It just seems like another obstacle on the roof that people don’t need so their solar power can be bigger if they choose to do so.
I was hoping that Marvin could find a way to put 4 – 6 265 watt Grape Solar panels on my proposed travel trailer. These were on sale once again at Home Depot for $1,200 for 4 of them. Last time I checked these panels were regularly priced at $1,399. If I got 4, then I was hoping Marvin could somehow get me connected to 4 portable Go Power 120 watts solar panels. So look for those Grape Solar Panels being on sale at Home Deport for those people on a limited budget. These are the most cost effective ones being mentioned on here at just $1.13 per watts while on sale. These are the 4th best on the watts per square inch as well.
About my Dream Travel Trailer – without drawing it out and only writing the approximate length down, it appears that it will be 32 feet. I was hoping that it would be between 27 – 30 feet. So this leaves me 3 options that I can’t think of right now. 1) Just leave it at my dream travel trailer length and not to be able to camp in 4 of the national parks 3 of these I have found boondocking spots for already. 2) don’t include the sofa at the end of the travel trailer to bring the length down to 29.5, which would enable me to camp in 2 of the national parks in #1 reply, and 3) just go with the 27’3” Arctic Fox travel trailer and be able to camp in all the national parks. I was hoping to go to the Novi Michigan RV Expo in October or I do believe the next one is in March and take along a tape measure to actually get some more realistic early numbers on the lengths of things. My bathtub is on a slant since I want to have a full bathroom complete with a linen closet so that was a real guess on my part.
We definitely have “excess” solar, but there’s many reasons for wanting that -> multiple cloudy days (a common thing), big power draws that suck down your batteries ( running your AC, for example), shade trees (which shade/block some of your panels). Having lived with solar for many years I’ve come to the conclusion that “you can never have too much” and we’ve never regretted having more panels. Just a few overcast days will do it and have you wishing for more. We loooove having excess solar.
As for TV we don’t have Direct TV so we use over-the-air when we can. Most RVs come pre-installed with an antenna, but you can keep it flat on the roof if you don’t use it. If you have satellite TV you certainly don’t need it.
Nina
P.S WordPress doesn’t allow me to move comments from one post to another, or at least I don’t know how. Certainly appreciate you keeping it on topic here 🙂
I am going to try to have a solar cabinet in the dream travel trailer. My question involves the lithium batteries. Is it possible to place 3 batteries on the solar cabinet floor and then place another 3 on the shelf above or would have I have to increase the solar cabinet width to fit all 6 batteries that I want? I can’t find it through my notes or searches, but want to confirm that the pure sine wave inverter goes into the RV basement or what does?
Here is a solar tilting system with multiple holes to choose from:
http://www.windynation.com/cm/Adjustable%20Solar%20Bracket%20Manual_R1%20(1).pdf
In one of Moeller’s books he gives a state and the tilting angle.
Here are a couple of links on phantom loads and RV electrical:
http://www.rvdoctor.com/2009/12/which-circuit.html
http://www.technomadia.com/2014/12/solar-planning-conducting-an-rv-electrical-consumption-audit/
I saw some 2017 message board posts on Nina’s set up. Here is what I come up with for Nina’s numbers.
3 200 amp hours batteries = 600 amp hours = 480 amp hours usable
Phantom draw = 60 amp hours/day
4 days = 240 amp hours after phantom = 60 amp hours/day
3 days = 300 amp hours after phantom = 100 amp hours/day
2 days = 360 amp hours after phantom = 180 amp hours/day
1 day = 420 amp hours after phantom = 420 amp hours/day
1500 watts solar panels = 450 amp hours per day
13500 BTU A/C with 14.16 amp hours
4 hours = 56.64 amps
24 hours = 339.84 amps
1 Fan with 1.35 amp hours
4 hours = 5.40 amps
24 hours = 32.40 amps
Your numbers might not be the same as Nina’s so you should see what your phantom draw number is, plus amp hours for the AC. Online I found a 13500 BTU A/C unit with the 14.16 amp hours and a 20 inch fan with 1.35 amp hour ratings. Once again your numbers may not agree with those. However, using Nina’s numbers from above and the amp hours for the A/C that I found, Nina could do a 24/7 AC with 110 amp hours leftover provided that she could get those 450 amp hours and how comfortable she felt in getting very low in the battery amp hour count. On cloudy and rainy days she wouldn’t want to run the AC 24/7. So Nina would have to get the weather reports online everyday to be on the safe side. If people want to run 2 A/Cs as I saw online, then the solar power would need to be around 2300 watts and that would leave practically nothing leftover for other energy uses. Using a fan would save 90%+ of the energy used over the same period of time. Everyone has to know what their average daily energy usage is. People can change their daily usage on some items. E. G. if I wanted my wife to cook one of my favorite dishes in the microwave for 1 hour, then I would have to give up the 4 hours for A/C, no washer/dryer that day, and then use the public shower so I could use the hair dryer. Those 3 items would be more than the microwave amp hour wise. So people can do trades offs if they do them properly.
I saw this book elsewhere on the internet, but then thought that I would do my own search and see what came up. Since you have a big rig, I was wondering if you heard of this book and might be useful for you to use. I know that the book is expensive compared to other RV books, but was more interested in the usefulness of it.
http://www.big-rigs-rv.com/Home.html
You can connect multiple Lithium banks together in a similar manner to regular lead-acid batteries (in parallel, then in series) so its best to have them all on one shelf for easiest wiring.
For the inverter/charger you can keep it inside (near the batteries) or in the basement. With the experience we’ve had with our system, I’d recommend basement if you can. The noise and heat of having the inverter/charger inside the rig can be bothersome under heavy load (e.g. running the A/Cs). It’s not extreme, but I think it’s nicer to keep it outside. If you’re going for a smaller inverter (not the big, honking Magnum inverter/charger that we have) inside would be fine.
Nina
I did want to have 6 lithium batteries if we full time RV. 11.18 inches * 6 = 67.08 inches so would make the solar cabinet 68 or so inches depending on what Travel Units recommended. I did want to place the batteries in a slideout. So the question remains whether to put the batteries in the bedroom or living area slideout while the desk goes into the other one.
Have you seen that Big Rigs book that I linked to in the previous post?
Not quite certain if we can full time RV as we can’t afford to take another financial hit. Another option would be to get the Northwood Arctic Fox travel trailer, but would have to give up a lot of my features (8 plus 3 others are bigger such as the refrigerator) plus smaller solar power system to making full time RVing easier besides making the black/fresh/gray water tanks smaller. Combined the 2016, 2017, 2018, and 2019 financial hits have totaled more than Nina’s solar power upgrade so it is a pretty good hit financially speaking. 2018 and 2019 financial hits are based on my wife’s new company policy. 2017 was a pretty good year financially for us as we were able to finally pay off the mortgage, max out my wife’s 403B contribution, plus the increase on the 403B plan not counting the contributions increased more than the previous 6 years combined (my spreadsheet only goes back to 2011).
Great information! I do have a question about your alternator and your generator on your coach. When the coach is running do you have to worry about it over charging your lithium coach batteries? Or if the generator is turned on ?
Ron
I have really been impressed how both you, Nina, and Paul have so willingly shared your knowledge about so, so many issues facing RV users. Your tuition costs were not free but you openly share all that you learned. I thank you so much, enjoy Europe; we are finally going to see North America via Renegade Classic; a bit late, but still able.
TJ Cammon