The “Big Beastly” Solar/Battery Upgrade Part III – Installation
We’ve had a whirlwind of activity since my last post, finishing our system installation, testing it extensively and (even) living off it for a few days but I’m overjoyed to say we’re up & running! So, I can finally take you all out of your misery and show you the nitty, gritty details of our installation. This is a looong post so let’s get going….
We Had Professional Help
First things first I have to give another shout-out to our solar guru/installer “Marvelous Marvin” (Marvin Braun of Precision RV). I can’t begin to describe what a huge job it is to install a system like this (especially one as complicated as ours) and there are so many details involved that having someone who understands RV solar (specifically) is a huge support.
Not only does Marv do awesome work (detailed, precise, pretty), but him and his wife are fellow fulltime RVers (for 13 years) who live off solar in their own rig pretty much 100% of the time. So he has real life, daily-use solar experience that a non-RVer just wouldn’t have IMHO. Lastly he’s been working with Lithium for over 2 years now and has done installations on all kinds of rigs from Airstreams to big ‘ol Class A’s.
ALL of the installation details (from where to place everything, how to wire it all together, how to protect our Lithium batteries) and all of the “extras” we got (e.g. installing a sub-panel for our inverter, installing a BMS bypass for our batteries etc. -> stuff we frankly would never have thought of on our own), were things he knew from experience would make perfect sense for our RV use-model. For our purposes, he was an invaluable part of the BBSBU.
Plus the cat approved, so there’s that too 🙂
NOTE/If you want to contact Marv for your own installation, he generally spends the winters in the Southwest and the summers kicking around the rest of the country, mostly the west this year (OR, ID, MT, CO, UT, NM, and surrounding states) depending on where work takes him. E-mail: marv@precisionrv.com, Phone: 206-276-2462, Website: PrecisonRV.com. We’ve got no affiliation -> just recommending good people for good work.
RV Solar Installation Is a “Leaky” Business
Before I dive into specific details of the BBSBU, I wanted to touch (very, very roughly) on a few key items. From an installation point of view, the most important thing to understand about solar is that it’s a pretty darn inefficient process. You only generate a teeny bit of electricity to start with (solar panels are only ~15-18% efficient, on a perfect day), and then every single step from there (from panels to charger to batteries etc.) is another potential loss. An easy analogy is to think of your solar setup like a big, leaky water system -> your solar panels are leaky buckets, your DC wires are leaky pipes and your batteries are the things that (hopefully) catch whatever is left over at the end. If you want your solar system to work you have to do everything you can to maximize the juice coming in and minimize those leaks going out.
From an installation point of view that means you want to:
- Avoid Panel Shade -> As I’ve mentioned before the biggest solar panel killer is shade, so arranging your solar panels with NO shade (from rooftop items) is key. Also wiring panels in parallel (rather than series) will allow you to have shade on one panel (say, from a tree) without affecting the output on any of the others. Lastly having the ability to tilt in winter is hugely beneficial.
- Target Short Wire Runs -> DC wiring is very “lossy” (= “leaky” using the water analogy from above) and one of the most common RV solar mistakes is to use wiring that is either too thin and/or too long for the current/voltage combo you’re putting through them. It can be a system killer! To avoid this you want to arrange all your big solar components (panels, chargers, batteries, inverters) reasonably close together and minimize voltage drops by using short, thick wire runs of the appropriate size.
- Set-Up Monitors & Controls Appropriately -> On the battery side you want to have a way to monitor how those batteries are doing plus you need set-up all the charging parameters appropriately for the type of battery you’re using. With Lithium there’s a few extra pieces to the puzzle too.
Useful Links:
- Blog Post: RV Solar Part IV – Panel Tilting & Winter Solar Optimization
- Blue Sea Systems: Choosing the Correct Wire Size for a DC Circuit
- No Outage.com: Voltage Drop Calculator
Things Specific To Lithium Battery Installation
If you read Part I of the BBSBU you already know all the advantages of going Lithium. But they also have some some limitations that make their installation needs different from lead acid. Most specifically they are more sensitive to heat/cold than lead acid and they will DIE (gone, kaput forever) if you discharge them too low.
-
LFP discharge capacities under different
storage temps and state-of-charge (source: “Calendar aging of a graphite/LiFePO4 cell”)Lithium Deteriorate With Heat -> Probably the biggest issue with LPF is that both their lifespan and overall capacity irreversibly deteriorate with heat. Since Lithium is a big $$ investment this is one of the first thing folks should think of before they switch. You really want to protect your precious $$ batteries from high heat, both during use & storage.
- Lithium Cannot Charge Below Freezing -> One of the other peculiarities of Lithium is that they cannot charge below freezing. They can deliver charge no problem (so, they can still power your coach), but you will damage them if you try to charge them below 32F. If you boondock regularly (or store your rig) in cold temps this is a definite consideration.
- Lithium Will DIE If You Discharge Them Too Much -> Another big issue with Lithium is that they will DIE (kaput, gone, like the parrot) if you discharge them too low. You can kiss your precious Lithium goodbye if individual cell voltage falls below 2.5V, so you must absolutely, completely avoid this. Most folks set the discharge cut-off at a safe 20% of usable capacity and you want to make sure this cut-off works FLAWLESSLY.
There are other details such as sensitivity to over-charging (Lithium can be permanently damaged by this) and having the ability to cell-balance (individual Lithium cells charge/discharge at slightly different rates and get “out of whack” over time) which means a good battery management & monitoring system are an important part of the installation too.
Useful Links:
- External Paper: Calendar aging of a graphite/LiFePO4 cell
- Battery University: Charging at High And Low Temperatures
- Elite Power Solutions: FAQ Section
Our BBSBU “Big” Installation Pieces
In our original solar system we had 6 panels arranged in a parallel configuration on the roof . The panel wires went into a single combiner box (on the roof) and a very short, thicker wire run went from there down the back closet of our RV to our charger, inverter & batteries, all of which were located in 2 outside bins in the very back passenger-side of our RV.
Our “new” system looks a bit different:
Our Battery Installation (= Nina Goes Drawerless)
Our #1 installation concern when we switched to Lithium was finding a place we could protect them from temp extremes. The outside bin (where we had our old lead acid batteries) was far too exposed. Not only did it get too cold on winter nights, but it got far, far too hot on summer days and we knew (from above) that this would deteriorate our precious batteries over time. So, we decided to switch up our battery arrangement and bring our batteries inside the rig. Since Lithium don’t vent, bringing them inside is not an issue and by doing this we were able to chose the best temp-controlled spot we could find.
We already had a nice wire run path from the roof down the back of our RV bedroom closet, so the most sensible place to put the batteries was in that same place. Not only would this keep all our wire runs nice and short, but that closet is well-insulated from both heat and cold (it never gets extreme in there). Plus it can easily be ventilated or heated as necessary if we need it.
From a practical point of view this meant I would need to give up my underwear drawer. This was by far the biggest “sacrifice” I made for the BBSBU and it gained unanimous approval from everyone (else). The dog didn’t see the point of underwear and immediately agreed, the cats were completely indifferent, and Paul told me I didn’t need one. So, I’m now officially drawerless** {oh well}.
Marv started by building a shelf for the Lithiums, strapping them down (so they won’t move around when we’re driving) and then wiring them to our battery management system (BMS). As a neat little “extra” he also added a master disconnect switch which means we can completely cut-off our Lithiums from our coach, if needed (useful as a backup hard battery cut-off or if/when we need to put the coach into storage, for example). Lastly he added a bypass for our BMS, another unique little “extra” that allows us to get around the BMS, if needed (e.g. we’ve gone below 20% and we need to bypass for a moment to start re-charging the batteries, or our BMS system fails/locks etc.). Everything looks fabulous and neat too, of course.
** Lest you all be alarmed, I managed to salvage a few precious pieces of underwear and transfer them to a drawer that contained some of Paul’s old stuff (now happily donated to charity). Wonder when he’ll notice?
Our Inverter Installation (= Move + New Sub-Panel)
The other big “switch” we made with the BBSBU was to bring our MS3012 inverter/charger from the outside bin to the inside of the coach on a shelf just above the batteries. This helped to shorten & simplify our wire runs. Plus Marv also made two important upgrades which allow us to use our inverter & new Lithium batteries to their fullest extent:
- On the input side of the inverter, he upgraded the wiring to handle 50 Amps and added a 50 Amp breaker (increased from the 30 Amp breaker that was there before).
- On the output side of the inverter, a sub-panel was added (we did not have one before) onto which lots of big “beastly” circuits were added such as our front air conditioner, washer/dryer, microwave and all general AC outlets.
Since Lithium are able to handle big “sucker” loads with no problems, this upgrade allows us to take full advantage of that. We can now run all our heavy-use electrical items (front air-conditioner, our washer/dryer) plus ALL our RV AC outlets directly from our batteries, making the very most use out of all that abundant, sexy Lithium power we have.
Our Solar Charge Controller Installation (= Modular + Internal)
As you know from Part II of the BBSBU, we decided to go to a “modular” charge controller system so that we could support our 2 different types of panels and our 3 different “solar systems”. Our four 3024iL Blue Sky solar controllers were installed in the the space underneath our Lithium batteries. This was previously empty space (underneath my underwear drawer), so it was the perfect spot. Marv also installed nice, big cut-off switches and breakers for each of our controllers so we can control each of our “solar systems” independently .
Our Remotes & System Controls (= Central Control)
We ran wire from our back closet through to the middle of our RV so that we could install all our remotes together and monitor everything that goes on with our solar/batteries in one place.
We have two panels in this spot:
- Battery Management Screen -> This links to our BMS system and tells us everything that’s happening with our batteries (charge level, voltages, capacity). The screen can also be switched to show individual battery cell details (voltage and temps).
- Blue Sky IPN ProRemote -> This tells us everything going on with our solar chargers including total system output as well as individual input/output (of each controller). Blue Sky also has it’s own integrated battery monitor so we have info that on this screen too. Lastly we can program all our charge parameters (voltages, absorb time etc.) “on the fly” from here too.
Our Solar Panel Installation (= 3 “Solar Systems”)
As I mentioned in Part II of the BBSBU, we had 6 old RV100 panels which we wanted to keep and we added 9 new (slightly lower-voltage) GS100 panels to the roof. Our top two priorities were to arrange everything on the roof to avoid shadows, and to limit the voltage drops on our roof-top wire runs (we used #10 marine-grade 90˚C wiring) to below 2%. To achieve all those goals we decided to arrange our solar panels into 3 different “solar systems”:
- System #1 -> We wired 5 of the new GS100 panels (500 watts) in parallel at the very back of the RV. This system is our lowest voltage system (Vmp 17.7V) so it was paired with the absolute shortest wire runs (less than 10 feet) from the panel to the combiner boxes.
- System #2 -> We arranged our 6 old RV100 panels (600 watts) in the middle of the coach. These panels are slightly higher voltage (Vmp ~20.5V) so they could handle slightly longer wire runs to the combiner box. These panels are all wired in parallel and are supported by two Blue Sky solar charge controllers (= 3 panels wired to each controller).
- System #3 -> We placed our final 4 GS100 panels (400 watts) in a series/parallel arrangement (2 parallel strings of 2 panels hooked-up in series) at the very front of our RV. By hooking two panels in series we doubled our voltage (Vmp 35.4V) for that string, thus enabling us to support the very longest wire run on the roof without any additional losses. This last system will also allow us (in the future) to do some “geek testing” comparing MPPT boost and shading effects on parallel versus series panels.
Our solar systems were wired into 4 combiner boxes at the very back of the RV, which gave us very short wire runs down the back of our bedroom closet to our batteries. Lastly we opted to use the same AM Solar Tilt Mounts we had on used on original system in 2010. They stick down onto the roof with 3M VHB tape and will allow us to tilt the back row of panels (whichever way we’re facing) if we want to. We may never need to tilt again with all the crazy power we have up there, but we wanted to retain that option.
Stuff We Will Add In The Future
There were a few, select details we didn’t get around to doing during our BBSBU which we will do over the next month or so:
- “Wireless” Support For our PCs/iPads -> Right now we have the Blue Sky Communication Module mounted inside our closet and we can plug into it with our main computers using a cross-over ethernet cable anytime we want to look at our detailed solar generation data. Our plan is to wire this to a router so that we have “wireless” access to our system anytime instead. We may even port-forward our data so we can access it from our phones when we’re not at home (totally geeky upgrade). I’ll write another post when we complete all this.
- Extra Circulation In Our Closet -> Although we’ve got very decent ventilation in our closet, we want to add some thermostatically-controlled fans (Marv recommended the Noctua NF-P12
as a good, quiet fan) to improve circulation if/when we need it. This is a minor addition, but will just enhance our temp control in that area.
Coming Up Next -> We’re not done yet!!!! I’ll be posting a final round-up with some real performance numbers PLUS the first (EVER) Wheelingit video featuring a full tour of our BBSBU system!
Totally Awesome!…..
That’s intense…
Hooray for no underwear!!
Oops… I mean, hooray for lithium! 🙂
Congrats guys, and awesome write-up… can’t wait for your first ever video!
Thanks! I’m a bit nervous about the video debut, but we’ll see. It’s going to be very casual.
Nina
Nina you are so cool to give up your drawer O’ unmentionables. I believe Mrs Boxin would have a caniption. What a girl does for lithium!
I’m a very special kind of girl LOL.
Nina
I like your putting the batteries inside; but I can’t do that. I’m a big guy; so my underwear needs lots of space. Plus, the combo washer seems to like where it lives. So, I’m stuck with the battery bay.
I know I can weatherproof it. I know I can really, really well insulate it. I THINK I can heat it if I can have another heat exchanger/blower added to my Aqua-Hot. They made the coach with one in the wet bay; so, maybe . . . . It would mean running the AH more than I probably would and burning some diesel molecules; but I can get that battery puppy to a cozy 38 or 40 and keep it there, (I think).
My problem is cooling. The only method I know of is to suck in air from below the coach and put an exit somewhere (?). I don’t think that’s going to do much in 90-deg temps but blow hot air around.
I’m thinking of using a dog-house A/C. They’re compact (relatively) and are 12V. The hoses could duct in and out through the floor.
Does anyone have any ideas on heating or cooling the lower compartment?
I’ve used these for a couple of years for my lithium batteries. I just placed the pads under the batteries and plugged them into the thermostatically controlled electric block. Can’t help you about cooling in hot weather other than to say move north in the summer. 🙂
Reptile heating pad
http://www.amazon.com/Flukers-Reptiles-Small-Animals-Large/dp/B00164PW9S
http://www.amazon.com/Farm-Innovators-TC-3-Thermostatically-Controlled/dp/B0006U2HD2
Cheers for sharing Robbie! Good tips.
Nina
So much to consider! Marvelous Marvin knows his “stuff”. Very smart to go inside with batt pack and inverter. Can’t wait for your performance evaluation write up, and video??
The Kittie cares..They just don’t like anyone to know….
Where in my state is Marv located?..I see the 206 area code.
Thanks,
David
They have a winter RV lot near Casa Grande, just south of Phoenjx, AZ.
Nina
Howdy,
> We may even port-forward our data so
> we can access it from our phones when
> we’re not at home
I would definitely *not* do that if I were you. These systems are not hardened enough to withstand “hackers” (actually crackers) messing with them though the Internet. And your exposure would not be just to the evildoers being able to peep on your solar power numbers: I think these systems would very probably be vulnerable to messing with their parameters to the point of making them dangerous.
I work with Internet security for a living, so I know what I’m talking about. Also, see the news about the entertainment system of cars being “hacked” (actually cracked) and the attacker manipulating the vehicle’s brakes, accelerator, etc.
The most secure setup would be a wired one, just as you have now (just make sure the computer it’s connected to either has no Internet access, or is very securely installed and maintained). If you connect it to a WiFi router, you’d better make sure the router itself is secure (or has no Internet access) *and* your WiFi parameters are very safe (ie, WPA2 only with no WPA or — God forbid — WEP encryption, very long and random passphrase, etc).
Cheers,
—
Vall
Yeah, there are definitely security issues involved with port forwarding. We do have a secured WiFi network and router so we’re definitely doing that, but I do think you’ve got a solid point on the rest. If we get too worried we may even just run some Ethernet down the rig so we can hookup directly by our desks.
Nina
Agree, the best way is to setup a VPN connection with your coach. This can be tricky to do with a WiFi ranger running the show. It would be great if VPN was added to the WiFi ranger.
That was a lot of information put together very well. Congratulations, it must be awesome to have so much solar!
It’s so complicated, so much to learn!
We can’t wait. Thanks for sharing and hooking us up. Marv is Amazing so glad you got us hooked up 🙂
Hope you have a great install. If you decide to go Lithium & end up writing about it let me know. I’m linking up to other lithium install write-ups in my next post.
Nina
We’ve been intrigued by this whole process. Thank you very much for the posts. Let me ask you: The cell batteries are completely removed from the RV?
Not sure I understand the question. Do you mean our old AGM batteries? Yup, they’re gone and caput. We used them as oversized paperweights for a few days and then recycled them. We DO still have our chassis batteries (coach starting batteries) and they’re in the same external bay as before. They’re still good and we didn’t move those.
Nina
It hadn’t occurred to me previously to move the batteries into the living space of the RV to help manage the temperature range the batteries experience. I so used to considering RV space premium real estate, losing half a closet to equipment usually in the basement wasn’t something I would have considered. Thanks for the idea!
The capacity degradation by temperature chart was very enlightening. Another alternative, I suppose, is active environmental control systems (heating and cooling) such as what is done in the electric automobile industry. As Lithium batteries mature, I assume the battery manufacturers will create self-contained systems that include the BMS, and environmental controls within a self-contained battery package. You see all of that in commercial solutions such as a Tesla Powerwall although that product isn’t suitable for a Motorhome. Thanks for the great post! There is SO MUCH to consider when thinking about going Lithium!
Temp control is definitely a huge consideration for Lithium. I know Marv has some some implemented some creative temp-control ideas in some of his other installations, but I couldn’t tell you much more. For us, bringing the batteries inside was the simplest solution even tho’ I did have to make some serious sacrifices to do so 🙂
Nina
Not really convinced about lithium. Do not understand not using more combiner boxes throughout the roof connections, Reduce wire runs on roof?
The wire runs are going to be the same length no matter where you put those boxes (you’ve got to get that electricity from your fixed panels to your fixed batteries somehow), and once you combine wires you need to use much thicker wire to carry the “combined” current from the box to your next contact point. Therein lies the problem.
The marine-grade (UV-protected) wiring I described above only comes in #10 size, so if you combine wires earlier on your roof you’d need to run thicker wire out the other end of the box and somehow shield that thicker, combined wire to wherever you’re able to run it inside the RV. Its not really practical and just makes more sense to run all your panel wires to a combiner box location right above wherever the wires enter your rig.
Nina
I have to ask what does a system like that cost and to install ? Great blog .
I’m drooling! Can’t wait for the lithium prices to drop. Nice set up.
Wow, quite the set up. You guys are ready for anything. Interesting to know about the lithium and temps too.
Lithiums are definitely more temp-sensitive than lead acid, especially to heat. One of the absolute worst things you can do to Lithium is store them at high heat for an extended period. They just slowly deteriorate and lose their capacity. It’s the same reason all the high-end electric cars (e.g. Tesla) have a cooling system for their batteries.
Nina
What an awesome setup! Thanks for all the great & detailed info. We are saving up for a solar install as well, will probably start with 600-800 watts, and definitely want lithium. Do you think $10-$15k should be enough?
Yup I think that’s definitely enough. Every job is a tad different, of course, but the range is around there. Also remember to factor in the 30% solar tax credit. You won’t be able to claim it right away (during installation), but you can claim it when you do your taxes after the end of the year.
Nina
I know, you don’t even have to say it, I’m cheap. Now, my question is; If you were to move on to another coach would you have Marv move everything to the new coach or would you have all the newest and lastest solar installed? This is an awesome setup and if the sun is shining you will never have to plug in again. Here comes the cheap again. Have Marv install a exterior plug so you can charge people to plug into your system and make some of your money back.
Oh I think we’d most definitely move the system if we moved rigs, or at least move part of the system. It’s one of the many reasons we went “modular” in our setup this time around. We’ve talked on and off about downsizing over the years (and we still may do that in a few years). With this setup we should just be able to take the lithium and 1-2 of the solar systems with us.
Oh and we’ll think about that plug 🙂
Nina
I wish I was more of a techie. About the only thing I understand about your setup is the indifferent cat. We have two. Looking forward to your continuing adventures of utilizing natures free energy. Now you need to work on free batteries.
So the real question is, are two cats more than twice as indifferent as one cat? I think somehow they are, but I can’t figure out the tech (cat-tech) details
Nina
What a surprise when I read your blog and saw Marvin in it. I’m surprised Ellen wasn’t helping him.
She did come over regularly to feed him lunch 🙂 It was actually really nice to meet them both, since we didn’t get to met Ellen during our first install back in 2010. We got to hang several times before we left.
Nina
Awesome looks great,Marvin did a great job
Great post,lots of good info
Awesome congrats.
Great informative post Nina!
Being able to run A/C without the generator and hookups is awesome. Will be interested to hear how many hours a day you’ll be able to run you A/C and if you had to doing anything special to the A/C to allow this setup to run. I’ve heard that a system called “soft start” may be required to damping the initial startup requirements of the A/C.
We’ve actually been looking at those soft start kits (also sometimes called “hard start” capacitors, confusingly enough). Right now our system can handle the initial surge, but we’re getting getting a very brief (momentary) fault on our inverter when we do it, so I think we’d prefer to soften that down for regular use. Plus the kit is only around $20 or so. It’s an easy, cheap upgrade.
Nina
Waaaaaay over my head, but what an amazing project!
We’re always astonished by how people like Marvin can make something so complex look so easy. Looks like he did a fantastic job. We would love a system like that, but will need a bigger RV first 🙂
Terrific post Nina!
We are considering a similar setup in the future and wondering if the inverter or charge controllers emit a noticeable hum while operating? No one describes the sounds of that kind of equipment in or near the living space.
Thanks for sharing your insight.
That’s a really good question, and it’s something I did worry about before we moved the inverter inside. After almost a week of pretty heavy testing I can tell you the following:
1/ NO discernible inverter hum under normal loads -> I don’t hear a *thing* from our inverter when we’re running all the regular stuff in the RV. So, for basic day to day use its perfectly quiet. Honestly can’t hear it at all (and I’m pretty darn sensitive to noise).
2/ Inverter fans DO make noise under heavy loads -> The only time the inverter makes noise is when the cooling fans kick on. Our particular inverter seems to have 3 fan levels. Level 1 is pretty quiet (not annoying at all), but levels 2 and 3 do get more noisy, and could definitely annoy you if you were in the bedroom. So far we’ve only seen level 3 under the heaviest loads (e.g. running the air conditioner), and in that situation the noise of the air con kind of washed out the noise of the fan. But I definitely wouldn’t be able to sleep with that noise. Far too annoying.
So bottom line, no noise under normal loads, but noticeable fan noise under heavy loads. I personally don’t think we’re ever going to run heavy loads at night (while we’re in the bedroom), so for us it’s going to work fine.
Nina
P.S. NO noise at all from our chargers or batteries. It’s only the inverter.
Very impressive installation. Being able to run one air conditioner is a big deal. Although if you spend your summers on the Oregon Coast less so.
Is this all hooked up to your auto start generator system too? Not that you would have to use it all that often, but once and a while you might need some power from the generator.
AGS becomes a bit tricky with Lithium because their voltage discharge curve is so darn flat. With lead acid there’s a nice, big voltage drop which makes the AGS easy to setup. Not so with Lithium. We CAN setup the AGS to trigger on temps, which is an option we may peruse. There may also be a way to trigger it based on amphours used (if paired the Magnum BMK)?? Haven’t looked into this yet, so this is still an open question we’re working on. Right now we have SO much extra power that I can’t see us using the generator much except in extreme circumstances (e.g. We need to run both air conditioners), so we’ll prob just ignore it for now and work on it down the line.
Nina
This would be simple if BMS CPU module had a programmable output you could use for gen start based on a given SOC.
That said, if you’re a programmer you could use the CAN or MOD bus options to monitor the BMS and do all sorts of things. That would be my plan based on the current product.
Question, any chance you have a schematic of your system you can share? If so feel free to send via email. I’ve been trying to figure out how to stop the Magnum from either over charging or drawing the batteries down to far using the two control outputs from the BMS CPU. It’s a common issue with inverter/chargers you don’t have with seperate inverter and charger.
Magnum could solve this with a small module just as they do with gen start so the BMS could independly disable the inverter or charger however they don’t seem to see the need when I discusses it with them. They think monitoring battery voltage is all that’s needed but that a hit or miss way of doing it with lithium.
Sorry, I don’t have a schematic. Marvin did the install based on his experience/expertise and we didn’t ask him for a schematic.
Nian
In the very best way possible – you are SUCH a geek! Great information and as always shared with simplicity and enthusiasm 🙂 Underwear are so overrated.
Thank you much…and I agree. I’m such a geek that when we chose the location for the Lithium batteries I immediately agreed followed by “what did we decide to get rid of?”
Nina
Excellent Article. I enjoyed reading it. Have you figured a final cost yet for the whole project?
Mel
Oh yes, we’ve already paid. Haven’t decided how much detail we’re going to share on the blog.
Nina
Nina and Paul, You went the full Monty! It’s very intoxicating just reading your post. Technology has excited me since dreams of street rods and rockets to the moon in the Fifties. Now, it’s the Bugatti Chiron and photon laser propulsion on a three day trip to Mars. After 5 years, my Lifelines are still performing well. But, like you, always making plans for the future. I was looking forward to your installation post, since everything I’ve read suggests an interior placement of the lithium batteries. Since LI batteries are a Goldilocks power source, it’s totally appropriate to install them in the bedroom. Thanks for the thoughtful and well written post. It makes for a great resource.
So very happy you enjoyed it! We’re definitely both tech geeks like you. In fact Paul and I wouldn’t even have met had it not been for tech, and it’s one of the many “loves” we share. It’s fun to geek out.
Nina
Nina,
Congratulations on your new solar setup! You can now go commando a few days of the week by giving up your underwear drawer space. LOL!
ENJOY THE POWER!
Great writeup! I am a full timer in a 2007 sprinter based Winnebago View. I have converted to total electric, even removing all of the propane system and appliances and the generator. I have 400w of Sinology lithium, bms system, Magnum 2000w sine wave inverter and 400w of AM Solar panels and all the safety, control and monitoring stuff. I am a geek of the first magnitude! i also installed a 280amp alternator (limited to 200a max) with an external controller (Balmar). I also have a dash mounted control switch to shut off the alternator or change it’s charge rate. I run my 12v refrigerator, expresso machine, microwave, toaster oven,induction cooktop, etc. Absolutely love the lithium system. Have done entire install myself, and the removal of propane and generator too. BTW, removing all that stuff and selling on Craig’s List went a long way to offset the high cost of the Lithium system! One more thing…I also use the lithium as my chassis battery system, completely disconnected the chassis battery. This vastly simplified the charging system, and provides more than enough power for everything. (I do still have the chassis battery as a backup, but have not had to use it in a year) Additionally, I have not plugged into shore power since I installed this system a year ago. (2 other notes, l live in southern California, so there is lots of sun, and I generally drive 400 miles a week or so. The charging while driving makes up for the 400 watts of solar. I regularly charge at 180 to 200 amps with the alternator)
Sweeeeeeeet system!!
A few of the items you mentioned are actually in our future/maybe list. I didn’t mention it in the blog post, but Marv actually installed a switch (in our external battery bay) for our alternator so that we can control when/if we want to turn it on. We did this mostly for safety (don’t want that alternator over-charging our batteries), but we hadn’t thought of adding a charge controller to it too. I LIKE that mod a lot! That way you can completely control how you charge while driving. We may not get to this right away, but we do want to do something more creative with our alternator set-up down the line, and your setup seems perfect.
I’d also read about folks (mostly boat folks) who use their lithium for their chassis too, and we’d thought that might be a nice upgrade for the day our chassis batteries croak. Lithium can totally handle those big cranking amps, so why not just use one battery set for both house and chassis? I love that you’ve done that mod too.
Awesome system! Thanks for sharing!
Nina
The need for a rededuntant chassis battery is removed when using a fully bms controlled lithium system. If an under voltage condition occurs because you leave a load on and draw thew battery pack down, the system automatically cuts the batteries off. when you return and discover that it is off, there is actually enough power left in the battery packs to start the RV. It is a simple process to over ride the auto shutoff and start the engine. The alternator will then begin recharging the batteries. Of course, with solar the chances of having flat batteries is minimized, except at night or a multi day solid overcast! The only time I have had the low voltage cutout shut the system off was when I accidentally did not turn off the toaster oven! I was sitting in the RV, and the battery system shut down. As I walked by the galley and toaster oven I could feel the heat from it!
I currently have 400ah of Lithium. It does suit my needs, but I’d like to add another 200. If I do, I like the Elite system that you have. I read up on it and it it is really a great turn key system. When I installed my system a year ago there were not any reasonably priced integrated systems available. Now AM Solar offers the same Sinopoly cells in integrated packages too. Much easier for non techy RVers to install!
By the way, may I ask which particular Balmar you use for your alternator charge control?
Nina
Nina, I use the Balmar MC-612 External regulator. It is programable, but not easily. I programmed it as close to Lithium parameters as possible. It is a multi-stage charger, but doesn’t really take into consideration the start -stop nature of driving an RV and charging Lithium. It does require that you rewire your alternator to allow for external control. It is rather easy, and many writeup and utube videos are available. it does have a half power mode that I wired to a switch on the dash. from there I can control full/off/1/2 charge. on the Magnum controller or my blue sky controller I can see the charge rate ( both are mounted directly above visor on the drivers side) additionally, my bms systems will alert me to potential overcharge conditions. I find that if I am driving for an hour or more that I will switch to the 1/2 power mode, dropping charge rate to 120-150amps. no sense in charging faster than that. If I am only driving for a short time I charge at 150-200amps. Also, the alternator I have is a 280 amp max with 100amp at idle. By programming the MC614 to max at 200amp it keeps the alternator cooler, and limits the charge rate to the batteries. my LithiumStorage.com Sinopoly SP-LFP200AHA batteries like around 70-80 max for each 200amp pack. They can take higher, but that does produce more internal heat, so I keep it down to 70-80 most of the time.
Great information here really appreciate. I have a 2006 road track sprinter having new battery boxs made up so I can carry 720 amp hour 4s 4p planning on running the AC in fridge off of Xantrex 1800/12v inverter and SBMS120 by ElectroDacus , in future (two years) solar panels don’t know how much I can fit on the roof . I will need to charge off alternator. I am wondering what amp alternator I would need ? I would mostly be using the RV on the weekends to drive two to five hours driving each direction.
For the alternator, if you’ve got lithium batteries you can pretty much go as big as your van can handle. Lithiums can take just about as much current as you’re willing to pump into them (one of their advantages) so if you choose a slightly bigger alternator, you’ll just charge that much faster. Just make sure you have some way to turn off/control the charging once the batteries reach their full state.
Nina
John, I know this post is old but I just read it. I’ve got a view and would love to add a compressor to my fridge and solar. I was wondering if there is a way we could talk so I can pull off the same as you?
Wow….all that and a free cat scan thrown into the mix….nice!
I know, right?! And we didn’t even have to pay extra for the cat scan.
Nina
Hi Nina! I sure enjoy your blog tho I tend to get envious every time I read it! 😉 On a different subject, I’d like to try an “around the country” trip: Spokane Washington to Northern Maine and loop back through the southern states. The question is the weather in the winter. Have you two ever come through the South in wintertime? Have any of your readers? Any advice?
Bill
The further south you go the warmer the winter weather. Most RVers knock around the SW desert (Arizona, California), South Texas or South Florida in the winter and all 3 spots are quite nice. The “in-between” states are different and can get chilly and/or the weather can get iffy, so you’ll probably want to keep a close eye on that as you’re going through. As an example New Mexico has quite a bit of elevation to it (it’s a pretty “high” state) so you definitely risk snow there in winter. It’s not a place I would chose to winter, but I would be OK driving thro’ depending on the weather.
So, my advice is to plan extended time in the most southern spots and just drive thro’ the rest as weather allows.
Nina
Nina, I forgot to ask if you have a BIRD2 charging system on your coach? If so, and since you apparently kept the existing chassis batteries, can you still charge the chassis batteries from the solar or shore power?
Good question! We could have done this, but we actually chose to disable the BIRD (it had died recently anyway) and add a Trik-L-Start from our Lithium to our chassis batteries. It’s not as fancy as the BIRD, but it’s a much cheaper/easier option for keeping your chassis batteries topped off.
Nina
Rock on with your no underwear overpowered self! What a drool-worthy set up. I can’t wait to see the video with the performance numbers! Very exciting stuff!
The question everyone is going to be asking themselves (and the one that will really get their noodle in a jumble) is “is Nina wearing any underwear in the solar video”? I’m not saying, not ever….
Nina
You definitely out did your Technomada friends. thanks for the overview.. Good Luck
HA! For the moment…for the moment 🙂
Nina
Sooo cool; having a bit of a geekgasm.
I have the same battery system (3x100ah) and bms. I’m very curious about how your disconnect solenoid is wired. I used two separate solenoids but am not happy with the setup due to the added drain, yours looks like it may be a better design.
Will you be providing details about running the air conditioning in a future posting? I can see running the a/c when you have good sunlight to keep everything charged. However doing something like running the a/c for 12-14 hours overnight with a cloudy day predicted, I think will drain the batteries to much. Or running the a/c on a warm humid 80 degree day with heavy clouds may be a problem.
Great write up though.
BTW in January I installed a 400AH lithium purchased from Starlight Solar and 650 watts of solar in my 29′ class A. I am just now starting to use the system. So far I love it. I did all the work myself.
I’ll probably cover this in more detail in a later post, but to give you some basic numbers our aircon consumes around 100-150 Amps, depending on mode. So, it just depends on your battery capacity and how quickly you’re able to refill them with solar.
Nina
P.S. Well done on installing the system yourself. It’s a ton of work.
Same setup from Marv on my Airstream. 15K AC pulls about 130 DC amps. With my 740w of panels I see about 35amps input. So need to pull 100amps from the batteries. 400ah Elite Lithiums and I can run about 3 hours. I saw a photo of the IPN that Paul/Nina posted and they were getting 90amps from their new setup. So with 600ah and a net draw of 40 amp hours they can go longer. There is still a place for a generator. I use a small Honda 2000 to supplement if I need to run the AC.
That’s the great thing about the Magnum Hybrid. It will mix Solar/Battery/AC power to gather and only pull what is needed from the batteries to meet the load after Solar/AC Power. A beautiful thing…
Its all about knowing the loads in your rig and how to manage all of the parts.
Makes sense. We’ve yet to see our max solar production (and how long we can sustain it), but I think we’ll end up being able to run our AC for a good chunk of time, depending on the solar day. We’ll do more extensive testing this summer.
Nina
Paul & Nina –
Can’t wait to see the first ever video! Wish your installer came out to the east coast…but we’ll just have to take a drive out that way some day.
Hi Nina and Paul,
This is a great post, full of details and good thinking/implementations of a fantastic solar power system for your motor home. Again, congratulations!!!
Waiting to hear your first hand usage experience of the great system…
Nina,
When we give tours of our off-grid house, people often ask “[I]f it isn’t all just too complicated?” I’ve come to explaining that it’s really just a scaled-up RV. You’ve given me the perfect example to point to. You have 15 panels for 1500W and we have 15 panels for 3300W, so, now, I can say we are just a double-D Beast. 😉
Kudos to Marv, too! Well done.
Pat
NICE!!! Double-D beast….too funny!
Nina
With 1500 watts of solar up-top did you see any need to go with a 16-cell 800 aH pack? Since I have an MS2812 similar to your 3012, how did you set up your Magnum for the lithium charging profile? It looks like Marvin wired the EMS OV/UV Alarm Outputs to an emergency pack disconnect relay. When that trips EVERYTHING shuts down instantly (my scooter shuts down completely) so for boondocking having an alternate means of starting the generator & engine will be a must. Wth all that “free” juice an Atwood electric 6 gal water heater sure would be nice! Several in my group have installed them and love’em…
This is your most awesome beast upgrade & tech write-up yet! I know, lots of questions… However, I don’t have a kitty or Marvin to assist me
Disregard on the water heater – I see you have a 20a CB for one. My coach has a diesel fueled Hurricane (like AquaHot) so I can use one. You should never need to bypass the BMS! After a 20% (I set my scoot at 30%) UV shutdown, the pack will quickly recover enough % to reset the UV BMS trip and that will allow charging. But I would never bypass the BMS to start any engine! Based on that comment I take it you removed or don’t have separate generator/engine batteries. Have no idea what the real brick-your-pack minimum is but testing that by going below 20% could be REALLY expensive! Way better to start your generator with jumper cables off the toad and let it charge the pack for a while than to risk $1,000’s.
Headed over to Elite in Chandler AZ next week 🙂
The BMS bypass is not for our engine. We still have our engine batteries and we would never use it for that even if we didn’t.
It’s there for emergency purposes only so that if we get below 20% (where everything shuts down and is cut-off) we can by-pass the BMS system momentarily to re-start the Lithium battery charging process (say, with solar or any other means) and get us back *above* 20%. Or if, for whatever reason, the BMS dies and kills everything and we want to be able to keep using the coach until we can get it fixed. Extreme cases we’ll likely never use (!), but we have it there just in case.
We would never use the bypass for going below 20%. That’s not what it’s there for.
Nina
We thought about going for 800AH. That size pairs nicely with our 1500 Watts (we are somewhat over solar-powered now, compared to our batteries, which is kinda how we like to be in general…our last system was that way too), but I honestly think our 600AH is going to be fine. Perhaps if we add a ton of electrically-powered stuff (in the future) we’ll feel differently. Right now our fridge and water heater can both be run off propane, so we have a TON of extra power. If we switch those maybe we’ll use a tad more, but I still think we’ll be fine.
As for our Magnum we programmed absorb to 14.1V (with absorb done set to ~8 Amps) and final charge stage to 13.4V. The final charge stage is set to SILENT mode. We set max charge time too, for safety. We may reduce absorb to 14V (very likely), but we’re still playing with those settings. At this point though, I can’t see us using our generator much (if ever) for charging. Our system is so large I just can’t see needing it.
And lastly, as I mentioned in the other comment we still have our engine batteries. We didn’t get rid of those, so we can always start the “beast” no matter what.
Nina
As mentioned above, lithiums recover somewhat after they reach the alarm cutoff point. Several years ago when I test ran the 60aH scoot pack down to the UV alarm cutoff, it shut down exactly as required. However, after 5-10 min with the key off it could be turned on again. That recovery takes it back above the cutoff threshold to power up the BMS for charging. Assume a pack with exactly the same BMS box but 10x larger would act the same way. With the balancing cards, I don’t know what a pack would do if one bypassed its BMS brain??
Looks like you have room if you find you need to squeeze in another 200 aH 🙂
Solar should provide most if not all of your electric. But there will be rare continuously cloudy/drizzlely weeks (OR/WA?) where either your gen or park power will be used to top off the batts, and of course there’s the AC use. That’s where the Magnum charger comes in. I sure wish Magnum would include a lithium charging profile in their next software update! With that much solar I doubt I’ll mess with engine charging of the coach batts. Without the appropriate safeguards, lithiums all-or-nothing charging ability can easily burn up an alternator.
With my all-electric coach I’m thinking 800 aH :), though I’ll need to figure out the rear closet space puzzle first. Didn’t see it mentioned, but do you already have a lightening arrestor on the combiner box? Lots of metal up on the roof leading to some very expensive equipment, so that’d be cheap insurance (Midnight makes a 300 watt version – on Amazon for $104.37). Marv seems to have thought of everything else on your install.
Have fun with your new “toys” and safe travels! 🙂
That Midnite lightening arrestor is 300 volts not watts 😉
Ah yes, for an all-electric coach I would definitely recommend 800AH. I think that would make more sense.
Nina
Always enjoy your site and do get new ideas. We left our rig at son’s place at 7500′ in mountains of northern NM two years ago and a year ago when we spent 3 months in Central America and South America. It got down to -20 F and the LFP suite was not damaged. The battery suite never dropped more than a few hundred W-hr a night and the charge rate was low (0.01C0. Had we been living in the rig at those temperatures, we would have left two 30 W lamps on in the front bay to keep the temperature above freezing.
We do keep a remote thermometer ($15 or $20 from any hardware store) and monitor it during the summer. Since the front bay is shaded by the hitch overhang, the front is not solar loaded. The temperature has never gotten over ambient. It was 103 between Campeche and Isla Aguada five days ago and the highest temperature in the bay was 93 F. We leave the three panels to the front bay open when parked since the inverter can get fairly warm (120 f according to the battey management system) when operating A/C from solar and battery: approximately 9 kW-hr at 48 V nominal) so it is important to get cross ventilation. We do have a number of 12 V fans (10 W) which we would use if it did get above 100 F.
Reed and Elaine
Cheers for chiming in w/ your arrangement. Looks like you have a good set-up for your Lithiums with decent ventilation.
Nina
Hi Nina,
great write-up (as usual). Thank you.
But I am a bit puzzled by the statement:
“On the input side of the inverter, he upgraded … and added a 50 Amp breaker…”
My wild guess is that the INPUT side of the 3000W inverter can suck in the ballpark of 250A @ 12.8V (not counting spikes). It looks like there is a “class T fuse” (300A?) on one of the pictures that goes to the inverter.
Also, I have a question about the choice of parallel wiring of the solars. Since you have MPPT controllers, wouldn’t it be advantageous to go with as high voltage as the controllers allow?
For the panel and Class T you’re looking at two completely different electrical items. One is AC and it’s a panel breaker and the other is DC and it’s a fuse. The Class T fuse is between the batteries and the inverter, and it’s discussed in the Magnum manual.
And as for panel voltage and putting panels in series. Besides the shade issue (which is a major concern and IMHO the main reason you don’t want a bunch of panels in series on an RV roof), there’s a difference between the max PV that a controller can take and where it’s most efficient (the Bluesky is actually more efficient at lower voltages). The key to remember is that MPPT doesn’t *create* any extra power. It simply makes the most use of what is there by converting what would otherwise be wasted power into usable electricity. There is always some loss in the whole MPPT process (with any electrical conversion there’s loss as heat). For us the MPPT function kicks in nicely on cold mornings (i.e. most of winter). In summer, when the panels are hotter (and thus lower voltage) we see it less.
Nina
Hi Nina. As a follow on to the previous question, I was wondering what the sub panel that was added was. Jack Meyer is in favor of a ‘main lug panel’ Since the breaker is being supplied by the main then the sub panel only needs to handle the 2 wires and ground. Since my inverter will be the xantrex sw 3012 and can handle L1 and L2, I need to decide if I should bring both legs or just one to the sub panel. In your case you seem to be doing fine on one so perhaps thats the answer as long as the other Leg is somewhat balanced in load. Sorry to hear about the family plans change.
Richard,
I’m pretty sure it’s a regular AC panel, made by GE. No part number on it (without taking it apart), so couldn’t tell you more. Marv only pulled one leg onto it since our inverter only handles one leg.
Nina
Thank you Nina. With some nudging and very specific help from Jack Meyer I put in the sub panel. In order to keep it RV like I used the same panel type that is the main panel from Progressive Dynamics and installed it within easy access of the basement door (5th wheel) http://www.progressivedyn.com/pd5500_2.html. Because The Xantrex 3012 is has the two lines, I’m taking two 30 amp lines L1, L2 from the main panel to the sub. That way the inverter passes both lines when not inverting and the total is not expected to exceed 30 amp single when inverting. The main power for AC, Water Heater etc are left on the main panel. The balance for the loads on L1 and L2 will remain pretty close that way. If we do substantially increase battery and solar panels in the future it will not take very much effort to switch over a line and send it to the sub panel. Your new system with the Lithium batteries sounds spectacular. Thanks!
Sweet! Sounds like you’ve installed a very exciting system! Cheers for reporting back.
Nina
2018 Installation Report! We just installed a 500AH Lithium system, and decided to put an article about it online, should anyone else be interested to hear our experiences.
http://kimartanddesign.com/Daves/JourneyToLithium.htm
This is years-on from your original feature, but I know many people still appreciate your blogs as such a useful source of info. Unfortunately we encountered an above-average number of problems (a disappointment given you’d expect systems to improve in a few years), but I hope this can still be of benefit to others (learning from them?!). And, apologies for our self-indulgence!