12 volt battery question please

pianotuna wrote:
~DJ~ so long as the batteries are charged it is better for them to be cold. It slows down self discharge about 50% for every 18 F (10 C) the ambient temperature drops.

Gdetrailer AGM do about six times better than FLA in the cold.

AGM will lose less capacity in the cold but it does have some shortcomings like higher upfront price, a bit lower Ahr capacity for the same given cu inches of space and has a few bad habits of gel cells on top of that to deal with and for good measure if overcharged high and long enough will breach the popoff valve and vent out what little precious electrolyte liquid it contains rendering it a very expensive doorstop.

Good note on AGMs is they typically do not off gas unless totally abused which means if you really must, they can be put inside your living area.

I have a bunch of UPS units around my house, they all came equipped with AGM instead of Gel cells, life of AGMs in "standby use" is far shorter than Gel cells. Older UPS units which came with Gelcells battery life was 5-6 yrs, the newer units equipped with AGMs I end up changing out 2-3 yrs..

Gets downright expensive after a while replacing AGMs.. So much so, have considered dumping the standalone UPS units, adding a dedicated Triplite APS series inverter/charger and yes, a pair of 6V FLA GC2s.. I can setup the GC2s/inverter/charger in a separate garage where my whole house gen lives and run inverter only power back to a couple of dedicated outlets.. Instead of needing to replace $60-$100 worth of AGMs every 2-3 yrs I would now have 10+ yrs of battery life.

Call me cheap, but dang those little wimpy AGMs hurt the wallet.

~DJ~ so long as the batteries are charged it is better for them to be cold. It slows down self discharge about 50% for every 18 F (10 C) the ambient temperature drops.

Gdetrailer AGM do about six times better than FLA in the cold.

theoldwizard1 wrote:

gbopp wrote:
You may want to remove the batteries at some point and inspect any metal near them for rust. Sand and paint as needed.
Just keep them charged while in storage.

Besides sanding and painting any brackets, keep the battery itself clean. Baking soda and water and an old paint/chip brush. Rinse with lots of fresh water.

IF you have a good quality converter, the FLA batteries will use very little water which means very little off gassing which means very little rust or corrosion.

Damage to the battery terminal seals can also create considerable damage by allowing the electrolyte to crawl up the battery terminals damaging your cables and in some cases extreme enough to wet the top and sides of battery. In this case, replace the batteries. Been there, done that.

With a converter that drops to storage voltage properly (13.2V) the water usage and hence the off gassing is pretty minimal. For instance I have a pair of 6V GC2s with a PD9160 with external charge wizard. Water usage for both batteries typically is less than 16 oz of water per yr. Terminals stay clean enough to eat off.

Here is a pix of my batteries I took in 2020, I have not touched or cleaned the terminals or the tops of the batteries since they were last replaced 3 yrs before the photo was taken..


Click For Full-Size Image.

Pix was taken after I added water so you can see a couple of drops of water, that is solely from adding water and not from boiling the battery.

If you have a converter that does not drop to storage, then that becomes a problem which boils the batteries very hard creating large amounts of off gassing which contains a considerable amount of acid.

gbopp wrote:
You may want to remove the batteries at some point and inspect any metal near them for rust. Sand and paint as needed.
Just keep them charged while in storage.

Besides sanding and painting any brackets, keep the battery itself clean. Baking soda and water and an old paint/chip brush. Rinse with lots of fresh water.

Back to the original question about foam insulation.

No need to protect the batteries with insulation, just fully charge them at the beginning of winter. Disconnect a battery cable and coming back in the spring to top up the charge.

If your batteries are difficult to remove (or to check the water), replacing them with AGM batteries wouldn't be a bad idea (since AGM batteries are sealed, and don't need water replenishment).

if you can? put a battery tender on them. make sure the water level is correct.

You may want to remove the batteries at some point and inspect any metal near them for rust. Sand and paint as needed.
Just keep them charged while in storage.

The key with wet cell batteries in low temperatures is to keep them charged. A small solar setup is what I used.

FLA will be fine without the need to remove or insulate provided they are stored pretty much fully charged. I suspect AGM will be the same as FLA.

FLA will not freeze as long as they have a decent charge, I suspect AGM will be simular.

Now if you are planning to use them during the winter, then insulating them to keep them a bit warmer will help some to keep cold weather capacity loss a bit less. Extreme cold temps reduces effective capacity in both cases.

For straight out storage, you do not need to insulate or keep them warm, just charge them to full, then disconnect the batteries from the house completely making sure you do not have any small phantom loads which will drain the batteries.

FLA can easily handle extreme cold weather stored in sub zero temps without freezing provided they are charged and as long as there is no other low power drain will easily go 6 months or more without the need for a top off charge.

AGMs are pretty much the same other than they have a much lower self discharge rate and can go longer between top off charges during storage.

Of course if you have shore power and a converter you can depend on shifting into storage mode (13.2V) you can just allow the converter to run 24/7/365.

Zero reason to remove or insulate the batteries for storage provided they are charged.. Some old habits do not die easily.

Contrary to the old wives tales, you do not have to store FLA batteries on wood to keep them off the concrete floor either..