Flooded Wet Cell Battery Discoveries
Texas winter storm problems continue to surface for me:
This post is just about helping others plan ahead. If you’re new to RVing there is information here that you probably won’t think about until you’re in the thick of it.
Over the past 3 months I’ve made several posts related to problems I encountered while wintering in Brownsville, TX, during the winter storm in February, 2021. The latest problem has surfaced:
Both, flooded wet cell batteries (Interstate SRM – 24 deep cycle) have apparently failed. I doubt most readers want the long version of what’s gone on the past few days, but the bottom line is this:
Because the power was out for about 30 hours while the temperatures dropped to just below 20 degrees F apparently the batteries were “killed”. This probably would not have happened if the batteries were fully charged while cold. Fully charged batteries are good to -80 degrees F.
I didn’t take my generator on this trip. I called ahead and was told “it doesn’t freeze this far south in Texas”. I lived for 20 years in Austin, and I know the odds of freezing weather is very low, so I believed it wouldn’t freeze and didn’t take my generator. But it did freeze, in a very historical way!
After the power went out, I was running the propane heat until it dawned on me the heater blower motor was running a lot. I hadn’t thought about this before, I just assumed it was a 120v a/c blower motor. It finally occurred to me it was running on 12 volts (batteries). It was very cold, and battery performance drops quickly as the temperature drops. Eventually, I shut the propane heater off (the batteries were down to 25%). I turned on the kitchen stove to supply heat.
About 30 days ago I took the trailer in for service; they are replacing the floor because when it got cold several washers started leaking water and water got under the flooring around the water heater and water pump. The service center said they would keep the trailer connect to shore power, but they didn’t do that.
One of the first things you learn when you buy an RV is………….. the batteries will go dead within a few days if you’re not connected to shore power and if you don’t disconnect the batteries. So, after about a month I went over to the service center to check on things and discovered the batteries were dead. I loaded them up and brought them home to try and revive them. After 48 hours of charging and “equalizing” I got good specific gravity readings in 4 cells in each battery. However, the outside two cells in each battery still read very little charge.
I contacted Interstate battery and their engineering and tech services Lab Manager contacted me. We ran a few more tests and he eventually conclude that the outside cells on each battery are either shorted or open, but either way, they won’t take a charge.
I’ve read numerous articles on battery equalization the last few days and with this info from Interstate I’ve concluded that:
If your flooded wet cell batteries run low in freezing weather, they can freeze at most temperatures below 32 degrees F. The colder it gets the lower the specific gravity becomes and the easier it is for the battery to freeze. I’m guessing the outside cells on each battery froze and produced open circuits in all four outside cells.
So, what can you do if you find yourself in a similar situation?
1. Take your generator with you.
2. I guess I should have connected my truck to the umbilical cable and used it to charge the batteries. I don’t yet know how much power the truck can provide, but after I removed the batteries, I did use the truck to run the slides in and out, and I’m guessing that’s at least 10 amps, maybe more. To me running the truck all night seemed like overkill, running a 5.7 liter engine to keep batteries charged, but in retrospect I wish I had done that. Actually, I don’t know if running the truck will actually charge the batteries. I need to find that out as well. (After the storm, it was 4 days before gas stations had gas to sell and 7 days before grocery stores had food.)
3. What other measures could someone take if they find themselves in a similar situation?
Dustin and Doris
2018 Crossroads, Sunset Trail 33CK,
38', 7600 lbs empty, 8300 lbs loaded.
2016 Tundra: 5.7L with towing package with added "Roadmaster Active Suspension"