Lessons in Cold-Weather Dry-Camping = Our Sierra Nevada Week-end

At least I have fur -> You should see the other guys!

It was going to be the COLDEST 4 nights we’d ever spent in the RV and for a wimpy-butt-chill-kitty like me that meant serious stuff. We were headed deep into the Sierra Nevada Mountains at about 7,900 feet near Mammoth Lakes. Day-time running temps were forecasted at a civilized 55-60°F  (13-15.5°C), but the nighttime thermometer was going to hit a MOST barbaric 18-20°F  (-8 to -6°C) and we were dry-camping without hookups {{swoon}} ! If it weren’t for the incredible views and stunning hikes (and the fact that everyone else thought it was a good (?!) idea) I wouldn’t be here, but as things stood I was ready to bear it out and take it as a learning experience. Very magnanimous of me, I thought…

And a learning experience it was. As with all life experiences it turns out there were a few things we knew, but a lot we don’t know about cold-weather dry-camping. Now, we were lucky that it didn’t snow during our time in the Sierra’s and moisture levels were super-low (so, no real ice/sticking/condensation issues), but we did pick-up a few tid-bits for our next time (should I ever be so insane again) in the chill:

1/ Lead-Acid Batteries Lose Capacity In the Cold

Rough graph of Battery Capacity vs Temperature
Rough graph of Battery Capacity vs Temperature

Being an avid photographer I’ve always known that batteries go faster in the cold, but for whatever reason I hadn’t thought about it for the RV. Lead-Acid batteries are “cold-blooded” which mean they slow down (i.e. internal resistance increases) and they actually lose capacity as temps drop.  The loss is pretty dramatic and gets faster the more load you draw (something called Peukert’s Law). What that means practically is your 220AH battery bank may only be worth ~150AH at 32° F (0° C), and even less than that if it’s colder and/or you’re drawing a lot of power (e.g. running a furnace). This little tid-bit explained why our 440AH battery bank was more than 50% discharged after a chilly overnight spell, even though we only drew ~150 AH from them. It was colder and so they had less to give! For more accurate graphs see the Lifeline Battery Technical Manual (Appendix section, page 34)

2/ Windows Are Major Leaky Cold Points

It’s all worth it for a view like this!

I love having large windows for views in the RV, but they sure are temp-suckers. Being nice, handy radiant conductors in summer they heat up the rig to a greenhouse boil while in winter they leak warm air out and manage to allow nice, chilly leaks to ooze inside. Closing out those leaks can mean MAJOR heat savings and as temps dropped below freezing we quickly realized we were woefully unprepared in this category. Here’s a couple of ideas we put in our back-pocket for our next trip:

  • Insulation Material – Our RV partners have a nice, handy foil-based Reflectix insulator on their big, front window and have Polartec material that they’ve sewed and velcro-attach to the inside of the smaller windows. Both these things made a huge difference in their rig (compared to ours) and we’re definitely stocking up on insulators before our next trip. Bubble wrap is another great, simple idea.
  • Plastic Shrink Film – I’ve talked to hard-core cold-campers that swear by those window insulation films that you shrink-fit to your windows. The positive is that they really seal things up. The negative is that you can’t open for air. Not sure we’ll need to go this route, but it’s a handy tip.
  • Better Shades – There are lots of shade options that do a much better job than the day/night jobs that we currently have in our RV. Old-fashioned Cellular shades or sleek, modern MCD shades can make a difference to both appearance and heat/cold tolerance. The MCD shades are on our “wish list”.

3/ Portable Heaters Rock

Our “Big Buddy” Heater

We have a Mr.Buddy (“Big Buddy“) that’s a great back-up/support heater to our furnace. We’ll often run it for a few hours before we go to bed to get a snuggly, warm temp and it turned out to be a major bonus for our Sierra week-end. You always, always need to remember to crack a window/provide ventilation with these guys (and make sure your CO detectors are working), but they’re portable, cheap and easy to use.

The Olympian Wave Catalytic Heaters  also get great reviews from RVers.

4/ Furnaces Can Suck You Dry

The fan in our furnace has a pretty significant power-draw (~10 Amps with both front and back going) and running it all night can easily suck us dry, especially when combined with other phantom draws and less battery capacity at low temps (#1). We managed to go below 50% batteries one night before we got wise to this one! We fixed this by switching to the portable heater (#3) before going to bed and sealing off our bedroom with only the back furnace on to keep us (and the pets) comfortable at night. As an additional back-up Paul set-up the auto-gen start on our generator to kick-in at 12.2V (~50% discharge point) on the batteries.

5/ Tanks Can Freeze, But It Needs To Be Reeeally Cold

It’s not cold enough here for a tank freeze…yet

If you’re consistently in freezing temps you’ve got to think about tanks and hoses. Typically cold-weather RVers will insulate or disconnect/put-away hoses and keep tanks warm with a small heat source or padding. Since we were dry-camping our hoses were already safely in the bay, but we did make the mistake of turning on our tank-warmer one night which (once again) almost drained our batteries. Duh! In reality our day-time temps were warm enough that we needn’t have worried about any kind of tank freeze, and if we’re ever in a situation that we do…well…I think it’s time to move the rig.

Who wouldn’t want to be here?

There are LOTS of other things that I’m sure we have yet to learn about. The good news is that our solar panels rocked the challenge (we managed to re-charge our batteries fully each day even though we didn’t bother tilting them), the cats did not turn into feline ice-cubes, and yours truly managed to survive with all fingers and toes in-tact. Oh…and it WAS worth it. The hikes, the views and the whole week-end rocked!

Click HERE To Shop Amazon.com

Disclosure of Material Connection: Some of the product links in the post above may be “affiliate links.” This means if you click on the link and purchase the item, I will receive an affiliate commission. That said, I only ever recommend products or services I personally use and love! Wheelingit is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com.

We LOooVE Comments, So Please Do

  1. says

    We camped near to where you were in September one year, on the road to Twin Lakes at a great little campground. It was chilly even then, but nothing like what you are experiencing. Thanks so much for all the information! Nice that there was sun to recharge your batteries at least.

    • libertatemamo says

      I didn’t see that campground? Is it a big-rig friendly spot?
      There weren’t many places open when we went (seems the majority of NFS campgrounds close around mid-Sept)
      but we’re always looking for other spots for when we come back.

  2. says

    Hope you had a chance to do the Virginia Lakes hike. It was our favorite, up to 11,000K plus and completely dog friendly. Gorgeous views and great hike past some lovely lakes.

    • libertatemamo says

      I managed to get a drive into Virginia Lakes last week while I was here w/ friends. Definitely a gorgeous spot! We didn’t do the hike, but it’s on our list for when we come back!

  3. says

    Lots of good info here. A question: where did you find information about MCD shades being better at insulating than day/night shades?

    And a comment: we used to have an Olympian Wave 6. When the pad needed to be replaced (about year 7), we switched to a Kozy World 2 brick propane heater. We like the Kozy World better in EVERY way, particularly the method of lighting it and the fact that it has a thermostat. We’ve camped in very cold temperatures in our 38′ motorhome and rarely use even half the capacity of the Kozy World. I have a rant about the poor customer service of Olympian on my blog… suffice to say, their poor customer service was the best thing that every happened to us in terms of getting a better heater!

    Our coldest nights have been in the 10-15 degree range, at my cousin’s ranch in SE AZ. We radiate so much heat off the coach that her horses’ water trough, 20 feet away, doesn’t form ice on the surface when we are there!

    Safe travels.

    • libertatemamo says

      Hi Laurie,
      VERY good info to know about the Olympians and the Kozy World. I’ll go check out your posts on it.

      As for the MCD shades there are a couple of spots that talk about the thermal barrier. The MCD website briefly mentions UV & heat control (which works both ways), but not in much detail. Most of the info I have is first-hand from several people that have installed them (incl. a couple just a few weeks back at Armitage), plus discussions on the forums that they help w/ heat/cold control. For example THIS thread.

      They do seem to provide a better seal with thicker material than what our regular day/night jobs do, especially with the 100% block-out option (the duo shades).

  4. says

    WOW…you kids are really adventurous! We are so glad that your solar panels work so well. What a plus! Here is wishing you warmer nights and more beautiful days!

    • libertatemamo says

      Thanks…! We’re already in ~15-degree warmer weather down by Lone Pine which has been just perfect.
      However there’s another cold-front coming this week-end so we’re moving even lower to the desert. I think we’ll manage to stay juuuust ahead of the real chills :)

  5. Martha says

    C’mon over to Fresno — it is warmer here! LOL! Glad it all worked out for you tho’ — looks gorgeous!! heading to Sequoia tomorrow.

    • libertatemamo says

      Oh how great! I really LOVE that area!
      We’re headed south pretty rapidly. Already in Lone Pine and going to Joshua Tree/Desert Hot Springs next.
      Should be nice and toasty there!

  6. DAVID says

    Love the dog picture….In case things freeze up, I use two old hairdryers to thaw the water pump and the dump valves….I can’t stand the furnace cycling on when it does….no quality sleep whatsoever…Oh memories of a hot springs between Stanley and Challis Idaho on a Halloween years ago, my suit was frozen in 2 minutes after I took it off. It was 8 degrees.

    • libertatemamo says

      YIKES!! Hot springs in 8-degree weather. That is pretty daring of you, even if the springs are hot!!
      That’s definitely beyond my personal limits for a swinsuit :)
      Oh, and THANKS for that great tip on using the hair-dryer. I’d heard it before but managed to forget. It’s a great little tip.

  7. says

    One thought on the 12.2v auto-start voltage for the generator: As load on lead-acid batteries increases, voltage drops. This doesn’t always mean that you’ve hit the discharge point that your voltage may normally indicate (under very light load after having a resting period). You have a large battery bank, but you can probably see this by turning a lot of appliances on for a couple of minutes and watching your voltage go from a solid 12.7 (or whatever) down a few decimal places or more. Then turn those appliances off and watch the voltage magically come up over the next little while.

    Can the auto-start function require that the preset voltage level be maintained for a certain period of time before it kicks the generator on?

    • libertatemamo says

      Veeery good question! In fact we had exactly the same one when we set it up. For our gen-start it seems it looks for the non-loaded voltage to drop before it starts. We tested it by pulling a bunch of loads (I even hoovered for 15 mins which takes loaded voltage to ~11.9) and it didn’t start up. But it did start when we let the batteries drain down under “regular” loads. I’m still not sure exactly how it works…whether it waits for a certain time or monitors the load, but it seems to work without kicking on under short-term high loads.

  8. jil mohr says

    sounds like you had fun anyway…we too employ things to keep warm…last year in Benson it was verrrrry cold……

    • libertatemamo says

      Oh yeah! I remember the pics you sent of some of the snow-storms that came thro’ the area.
      I’m sure you guys are “pros” at staying warm!

  9. says

    As always – awesome information! We are currently plugged into our rental home and temps have *only* reached 35 at night. Still quite chilly, and we’re plugged in so I can’t imagine colder temps & less power. Great to hear about the solar panels doing the trick and I will have to do some research on shades/window tint. We’re trying to decide how much really warm or really cold weather camping we will do. We’ll find out soon enough as we finally leave tomorrow! :)

    • libertatemamo says

      At some point somewhere you’ll end up colder or hotter than you planned for :)
      The insulators are probably the best and cheapest additions you can make. They will help with BOTH heat and cold.
      Can’t wait for you to get on the road! Good luck w/ everything!

  10. says

    YEAH! to all those things. We discovered most of them wintering in NYS, but we had the luxury of being hooked up to shore power all winter. That meant the batteries stayed topped off, and we could run the furnace. Everything else was as you described.

    About the shrink-wrap for windows. Very helpful, but we have still not gotten all the sticky off the metal window frames. Oops.

    • libertatemamo says

      Ahhhh yes the sticky stuff. I can totally see that. Good to know it worked, but not sure we’ll be using it unless we Reeeealy have to.

  11. Brent says

    We use the back furnace with the door closed trick almost all the time in cold weather. Keeps us plenty toasty, warms the front just a bit and heats the basement / tanks / pipes without killing the battery

  12. says

    Brrr!! We were pretty deliberate about avoiding cold temps while in the RV (and we’re actually following a similar pattern while on the road now – I hate being cold!), but we did have a below-freezing night in the Smoky Mtns that froze our outside water hose. When turning on the faucet in the morning didn’t lead to any water coming out, of course we freaked out…. but thankfully it wasn’t a big deal! That moment of total fear was the worst, though. 😛

    • libertatemamo says

      Frozen pipes are definitely something that’ll scare you, esp. in an RV where a burst pipe can mean no water at all.
      Glad you guys got thro’ it!

  13. says

    Propane space heaters in RVs overnight while you are sleeping make me very nervous. I had one put in our last smaller type A coach. I mostly stopped using it. You have to open a window or vent to use it. I never left it on while we slept. At this time I like our setup for cold. Although we normally follow your flip flop travel plan so not much heat needed. We have an all electric coach, which I like, and it has aqua hot diesel heat. It is very efficient and uses little electricity. When we are in an RV park with electric we normally use an electric space heater.

    Unfortunately an aqua hot is likely expensive to retrofit to your coach.

    • libertatemamo says

      I REALLY like the Aqua Hot system. Our caravan buddies have it in their coach and WHAT a nice feature that is! Unfortunately the retrofit doesn’t make sense and it’s likely a feature we won’t get until the day we decide to upgrade to another coach.
      I do also agree on the safety w/ propane space heaters. We always make sure to have a vent open and NEVER leave it on while we sleep. Still, it’s been a great little heater for our travels and helps get the chill out of a cold evening.

  14. Greg Seed says

    Seems like you two are on a great journey. You are sharing with us quite a unique perspective. As I scroll the web I haven’t really found posts with the wanderlust you seem to convey. Really enjoying this Wind that you two seem to be riding. See you out there Someday
    Many Thanks

    • libertatemamo says

      We sure are enjoying the ride and glad you’re enjoying it through the blog too. It’s a fabulous lifestyle :)


  1. […] When it’s really chilly outside there’s no better way to cozy up than a nice heater in the rig. We’ll turn on the big RV furnace when it gets really cold, but it’s kind of noisy & does draw ~8-10 amps of battery power to run. For the majority of our hanging time we prefer the versatility of the Mr. Buddy Propane Heater (there is also this smaller size). We always crack 2 windows (for through air-flow) and only ever use it while we’re awake, but we just love it! We can move & place it anywhere in the RV, and if we run it on low setting we get ~8 hours of good heat from 2 small 1lb bottles. Some RVers prefer the fancier Wave 6 Catalytic Heaters (or, the larger Wave 8 size) and will mount them permanently inside the rig. Either way, an electric-free heater is an awesome addition for boondocking and we wouldn’t be without it. Related Post -> Lessons in Cold-Weather Dry-Camping = Our Sierra Nevada Week-end […]

A Comment For Your Thoughts?

Your email address will not be published. Required fields are marked *