Protect Your RV Batteries While In Storage
With freezing temperatures sweeping across much of the country, many RVers have already winterized their RVs to prevent the plumbing from freezing. But how many of you have taken precautions to keep your lead-acid batteries from potential damage during the winter?
Throughout the years, I have met many RVers who ruined their batteries by not taking steps to protect them while stored during the off-season. Here is why this can happen and what you can do to prevent it.
Don’t drain your RV batteries
Most RVs have parasitic 12-volt loads like gas detectors, stereo clocks, circuit boards, etc. that slowly drain your battery over time. Why is this bad for your batteries while in storage? Well, unless you have the luxury of leaving your RV hooked up to shore power or have an above-average solar charging system, your batteries will become discharged.
Completely discharging your batteries is undesirable for two reasons: 1) Every time your batteries are drained under 50% of rated capacity, it shortens the life span of the battery. 2) The fluids in discharged batteries can freeze.
The expansion of the fluids will often cause the plastic housing of the battery to crack, ruining the battery. If you have adequate solar charging, make sure the panels remain free of snow accumulations.
Winterizing your batteries
The following are several steps you can take to protect your RV batteries while the RV is stored for the winter:
- Keep your batteries charged as a fully charged battery can withstand extreme subfreezing temperatures.
- Use a battery kill switch to keep parasitic loads from draining your batteries.
- Store your RV in a climate-controlled space.
- Remove the batteries from your RV and store them in your garage (provided your garage stays above freezing). Contrary to popular belief, it is okay to store your 12-volt lead-acid batteries on the concrete floor in your garage.
Regardless, if you remove your batteries during the off-season storage or keep them in your RV, it is a good time to service your batteries by making sure they are clean and cells are filled to the appropriate levels with distilled water.
Pete’s RV also shares some great information on winterizing batteries in this video:
By taking the steps listed above, you can protect your batteries from becoming a casualty of winter—because dead batteries are an adventure in RVing none of us want to experience!
Keep track of all your RV maintenance with an online tool such as RV LIFE Maintenance. Not only can you keep all your maintenance records and documents in one place, you’ll receive timely reminders via email when maintenance is due and potentially avoid a costly repair or serious accident.
For more details, see our previous post on Why It’s Important To Keep Your RV Batteries Charged Properly.
Dave Helgeson’s many roles in the RV industry started before he even had a driver’s license. His grandparents and father owned an RV dealership before the term “RV” had been coined, and Dave played a pivotal role in nearly every position of an RV dealership. He and his wife Cheri launched their own RV dealership in the Pacific Northwest. The duo also spent 29 years overseeing regional RV shows. Dave has also served as President of a local chapter of the Recreational Vehicle Dealers Association (RVDA), worked on the board of advisors for the RV Technician Program of a local technical college, and served as a board member of the Manufactured Home and RV Association. Dave’s reputation earned him the title of “The foremost expert on boondocking,” bestowed by RV industry icon, the late Gary Bunzer (The RV Doctor). When he’s not out boondocking, you’ll find Dave in the spotlight at RV shows across the country, giving seminars about all things RVing. He and Cheri currently roam in their fifth travel trailer, with Dave doing all the service, repair and modifications to his own unit.
I’m just curious, but why is it that a charged battery can withstand below freezing temps?
Dave Helgeson says
The electrolyte inside the car battery is made up of about 25 percent sulfuric acid and 75 percent water. The acid interacts chemically with lead plates to create electricity, leaving mainly water in a discharged condition that is more susceptible to freezing.
When charged, the electrolyte solution is at its highest concentration and can tgen only freeze at way lower temps than pure water. Similar in concept to why salt water resists freezing but moreso. When discharged, the solution is at lower concentration and so it can freeze at a higher temperature but still not quite as high as what pure water will freeze at.
A discharged batteries’ electrolyte is closer to water.
A charged batteries’ electrolyte is closer to acid.
bob wire says
should i rely upon solar power maintainer geo pro 19QB or just to be safe take battery out? would have to either store in unheated garage or bedroom closet
R Alonso says
We do not have a freezing issue here in California. Having said that, I keep my RV hooked up to shore power always; however, if I use my battery disconnect switches the main battery starting battery will “forget” its factory settings and be very difficult to start when I’m ready to go again. Any ideas as how to overcome this?
Harry Armstrong says
A charged battery contains acid vs. water in a dead battery.
David Childers says
I do have my camper connected to shore power. Is there anything I need to do to my batteries in this scenario?
E Bergler says
A full battery contains acid but as it drains acid gets more and more watery and then it can freeze!
So keep them charged
Dave Helgeson says
David – If you have a quality 3 or 4 stage charger that won’t overcharge / boil your batteries all you need to do is occasionally check the fluid level of the cells adding distilled water if needed.
FRANK GRASHA says
The water in the battery has chemically changed its specific gravity From charging to Sulfuric acid (which has a much lower freezing temp) As the battery discharges the acid returns to straight water Which will freeze @ 32o A couple days of below freezing will cause Ice to expand and break the case ! JUNK !
Dan Nowell says
Doug :batteries are essentially made up of a series of coated lead plates in a plastic box full of sulfuric acid. As a battery discharges ions are stripped from the acid and attach to the plates converting the sulphuric acid to water which freezes. It is actually more complex than that but that is essentially what happens!
At the marina in Ontario where I work we simply remove the negative cable from the battery and leave them in the boats. Many of those batteries are 6-10 years old and are still charged in the spring.
DEAN REYNOLDS says
The fluid has a depressed freezing temperature because of the acid.
Barry Thomas says
Doug, what is the process if you leave batteries installed with shore power ? Turn off Kill switch, or does it matter? Keep cell full. Etc ???
Norm Hamlin says
The active ingredient in a battery is H2SO4 (Sulphuric Acid). It has a freezing point far below that of water. As a battery discharges, sulphates end up on the plates and the liquid in the battery becomes closer and closer to H2O.
A fully charged battery has a specific gravity of 1.2 meaning a given volume of the liquid weighs 1.2 time an equal volume of water. A discharged batter6 has a much lower specific gravity.
Nick Cockrell says
When a lead-acid battery is discharged, soft lead sulfate crystals are formed in the pores and on the surfaces of the positive and negative plates. When left in a discharged condition or excessive high temperatures, is continually undercharged, or the electrolyte level is below the top of the plates or stratified, some of the soft lead sulfate re-crystallizes into hard lead sulfate. These crystals cannot be reconverted during subsequent recharging. This creation of hard crystals is commonly called permanent “sulfation”. It is the leading cause and accounts for approximately 85% of the premature failures of lead-acid batteries not used on weekly basis.
JOEL MCGREGOR says
You can buy chargers that reclaim sulphation if it isn’t too bad. Battery Minders do.
Jerry Albright says
The liquid in a charged lead acid battery is acid, which freezes at a lower temperature. When the battery is discharged, the acid turns to water which freezes at a higher temp.
Michael Fraley says
My garage gets well below freezing in the winter. Is it safe to store RV batteries in my basement? Do they emit any hazardous gases?
Douglas Sick says
I have solar panels. Is it OK to leave them with an open circuit if the batteries are removed?
David Baughman says
If my single battery is removed and placed safely in my garage to maintain, what about the 2 solar collectors on the RV? Is there anything that should be done? Should the disconnect be off? How about the inverter?
A fully charged battery with full isolation will stir through winter well without trickle charging! Have done it for 30 years in Green Bay, WI, and never an issue.
If I store my coach inside, can I attach a small, inexpensive trickle charger?
If yes, where (which posts) do I attach it to?