If you let your lead-acid batteries boil and dry out bad things can happen…
Dear Readers,
These pictures just came in from one of my Facebook Group members. Yes, it is indeed as bad as it looks.
A battery explosion
It appears that the multi-stage charger might have failed and kept pumping significant current into the batteries, after it should have gone into “float” mode. The poster noted that he only had to add water every 6 months, so he consequently only checked water level every 6 months.
This was compounded by how far he was away from the RV, so it would often sit for 6 months by itself while plugged into power to keep the batteries fully topped off.
Batteries are potential bombs
So, all was well until apparently something happened with the multi-stage charger that caused the water to boil out the batteries, one of which exploded. When the water boils out of a lead-acid battery and exposes the plates, there can be serious outgassing of hydrogen and oxygen gases in the perfect ratio for an explosion.
If these gases accumulate in the top of the battery due to a void from a lack of water, then it only takes a spark from one of the overheated plates to make a small bomb. And it’s powerful enough to blow up the casing of the battery and spray sulfuric acid over everything in the area. Then you have some serious cleanup to do in addition to replacing the batteries.
What to do?
First of all, never leave your battery plugged into a standard trickle charger or old-school 2-stage RV converter/charger. That’s just asking for overcharging trouble. Also, I highly recommend monthly checks of the electrolyte level in your FLA (Flooded Lead Acid) batteries. While it may not be convenient to do this in some RVs where the batteries are located in a hard-to-reach location (like under the steps), nonetheless, checking the electrolyte level monthly is very important. Don’t become my next poster child for battery explosions.
Making it easier with Flow-Rite
I haven’t completed my review of the Flow-Rite battery watering system just yet, but I’ve had a number of unsolicited testimonials from readers who have used the Flow-Rite system for years with great success. They note that it only takes two minutes to check the electrolyte level on up to four batteries at the same time, and fill them with distilled water.
Best of all, you don’t even have to touch the batteries to check the level. There’s just one place to fill and you’re done. Seems like the real deal to me – which is why I asked for a review sample from Flow-Rite Controls™, Ltd. As soon as it warms up a bit I can complete my review. Brrrrrrr!!!! In the meantime, you can find Flow-Rite products on Amazon HERE.
Charging options
If I needed to leave an RV unattended for 6 months at a time, I would consider shutting off all shore power to the RV and hooking up a Battery Tender instead of the on-board multi-stage battery charger.
Battery Tender has a great reputation for making a product that floats your FLA or AGM batteries perfectly. And you can even get solar versions in case you need to store your RV in a spot without electric power, but that does have sunlight. Just remember that Lithium batteries don’t need (or want) to be float charged in most cases. But check with your battery manufacturer just to be sure.
What about Lithium Batteries?
You’re in luck if you have Lithium batteries. Since they lose very little SoC (State of Charge) while in storage (typically around 1% per month) you don’t need to charge them at all over the winter. In fact, most of the Lithium battery manufacturers recommend you just charge them up to 100% SoC and then disconnect them. They’ll still be around 95% SoC five months later.
OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.
Let’s play safe out there…. Mike
The other common cause of this is a bad cell in one of your batteries. This causes a low voltage condition which causes the charger to “think” the batteries need more charge.
Yes, I’ve seen this as well. And a conventional charger will overcharge the remaining battery cells with predictably bad results.
Hey Mike, I’ve used the Flow rite system on both a bank of four 6volt for six years, and now two years on a bank of two 12 volt batteries. I have had no issues with either. Makes it so easy to perform monthly maintenance. Before installing this system, in order to get the caps off, I would have to actually disconnect some of the cables. This would tend to make me procrastinate this dreaded task. I would highly recommend this system to anyone that has batteries in a difficult to fill or access situation.
Hey Mike, I’ve used the Flow rite system on both a bank of four 6volt for six years, and now two years on a bank of two 12 volt batteries. I have had no issues with either. Makes it so easy to perform monthly maintenance. Before installing this system, in order to get the caps off, I would have to actually disconnect some of the cables. This would tend to make me procrastinate this dreaded task. I would highly recommend this system to anyone that has batteries in a difficult to fill or access situation.
I’ve been using the Flow-Rite watering system for over 12 years & 200K miles in our 54th wheel with four 6volt batteries. We now have the 5er parked on the Gulf Coast & travel for 6 months at a time in our new triple slide truck camper. I have a very elderly woman on a nearby lot who goes over & checks on our 5er each month while we’re gone. She says she loves topping off our batteries because squeezing the bulb is so easy, even she can do it. All she does is stick the tube in a jug of distilled water kept next to the batteries & then squeezes the bulb until it won’t depress any more. It literally takes her no more than 20 seconds to fill all four batteries. She doesn’t even have to lift the battery compartment cover to look at the batteries. The Flow-Rite system is the greatest system since sliced bread. Because of this easy watering system, my 7 year old batteries still test over .1275 hydrometer readings & all cells are showing very similar numbers. This shows that even after 12 years, the Flow-Rite system is still properly toppinng off each of the 12 cells in the four batteries.
I had flow rite on our SuperC – IMO its and absolutely horrible system, and very pricey! Its a crutch for maintenance that needs visual / hands on inspection.
You had a chance to say “stoichiometric ratio” and missed it!
HI Mike,
Regarding lithium batteries, my understanding is that they should NOT be stored at 100% charge, as doing so can damage them. The recommendations I’ve seen from manufacturers is that they should be discharged to ~50% before storage and preferably be kept between 20% and 50% SOC. Have you heard something different?
Most manufactures I’ve contacted recommend storing Lithium batteries at 100% SoC, but a few recommend 50% SoC. I’ll try to pull a chart together and post later. What brand battery do you have?
Mike – Great Stuff. I had two 12V Deep Cycle maintenance-free batteries connected in parallel to my 2022 5th wheel.
However, one of the batteries got hot and boiled off some of the water. Good thing my son caught it.
I was looking at the batteries, and I would have to really work at checking the fluid in the batteries as they are “sealed”.
Could you address what battery manufactures have RV deep cycle batteries we can view and top off the electrolyte solution and what exactly you mean by “old school two-stage RV Converter/chargers” and provide examples of “good converter/chargers”.
I hope that my 2022 coach’s charger is not in the old school category.
Thanks for all the great articles.
Sounds like an idea for a future article…