Battery winter storage

JNorton wrote:
Which is exactly why I no longer use trickle chargers. If the kids unplug it from the extension cord the battery is toast 3 months later. My C sets in a field with no power available. I disconnect the battery and I've never had a problem starting it right back up in the spring. I do the same with my motorcycle - never had a problem. Except as stated above when the trickle charger was disconnected. Keep it simple.

If mine gets unplugged when being maintained by the Noco, there is no drain. It's as if I just have the battery disconnected. That is why I have it set up that way. A good maintainer will not be a parasitic load on a battery when power is removed. There are chargers that will impart a drain on batteries if power is removed. Be careful when choosing and get one that is designed to be left connected to a battery even when unplugged from AC.

Wow! When I posted my query, I had no idea that the subject would yield so much reasoned discussion. Thanks to all posters, but I confess to continued confusion. I think I will go with the disconnect/trickle chargers. Thanks for all the info!

Jim

Flooded lead acid batteries self discharge between 4 to 6 percent per month with discharge rates diminishing with lower temperatures. Typically a fully charged battery will suffer no ill effects being disconnected for winter. If you do choose to use a float charger use a holding relay to disconnect it from the battery in case the power fails. Make sure it is a float charger rated for your battery type. https://en.wikipedia.org/wiki/Float_voltage

The longer a battery sits, the more sulfur comes out of solution and coats the plates. The thicker they get coated, the closer the battery gets to failure. Extend the life of your battery (only 30% of batteries live to their life expectancy because of improper care) by keeping a float charger connected 24/7 if it's in storage for more than a few weeks. They're not expensive and last for many years.

We leave ours in the RV. We have 2 of them. I connect a power cable to it every couple weeks to keep them charged. Crank up the RV (once or twice a month) and let it idle for a little bit. Run the genny.

Which is exactly why I no longer use trickle chargers. If the kids unplug it from the extension cord the battery is toast 3 months later. My C sets in a field with no power available. I disconnect the battery and I've never had a problem starting it right back up in the spring. I do the same with my motorcycle - never had a problem. Except as stated above when the trickle charger was disconnected. Keep it simple.

Bordercollie wrote:
I keep the rig connected to 120vac power, have a modern PD9245 converter charger that will not boil out electrolyte of house batteries. I have a Trik-L-Start device installed that keeps the starting battery up. Any charging device will deplete electrolyte levels so it is wise to check and replenish electrolytes with distilled water if/as needed. All wet cell lead-acid batteries self discharge over time so they need smart trickle chargers like Battery Minder to keep them fully charged but not over-charged.

There is one down side to this. I also have a PD converter and Trik-L-Start. If there is an AC power failure (like the power cord gets unplugged) the batteries will no longer be charging and in fact be discharging through all of the parasitic loads. That is why I mounted the battery charger/maintainer independent of the coach wiring. I can leave the house switch OFF and if the AC power fails, there's no parasitic load. You guys have exactly one guess as to what caused me to head down this route.

OK, I surrender. No battery should ever be heated, under any conditions, unless the thermometer is going below -60. Real world variabilities be darned.

If the batteries froze then they were not fully charged, or had parasitic loads on them.

I live in a climate that does get to -40 and I have personally rv'ed at -37 c (-34 f). My batteries never froze because they were kept charged.

A five year old battery may have reduced capacity, but if the specific gravity can be shown to be 12.75 then the battery will not freeze until it is -60 c (-77 f). Further, the colder the temperature the less self discharge happens, so storing at -20 c is much better than storing at -5 c.

Plugging in a car or other vehicle is about warming the oil. It does not warm the battery, unless a battery blanket has been added.

Very few homes are designed to withstand -60 c (-77 f). I repeat there would be other more important problems to address.

While I'm sure your nephew is honest, he is not being given correct information. All cars now have parasitic loads. In cold weather that becomes a big problem.

pianotuna wrote:
Bobbo,

A fully charged battery will freeze at -60 c (-77 f).

The term "fully charged" is important there. After 5 years or so of service, how many batteries will hold what we refer to as a "full charge"?

pianotuna wrote:
No need to plug in until then

Unless you are going to bed at -50 and don't know how far it will dip at night.

pianotuna wrote:
and at those temperatures there are more serious issues to address, such as not freezing to death.

I assure you, they were sleeping in heated houses.

If you have issues with what they do in Alaska, as observed and reported by me, I urge you to take that up with the folks in Alaska. My nephew told me he has personally seen cars that had batteries frozen when the owners failed to plug them in. As a Tech Sergeant in the Air Force, I hope he has enough integrity not to lie to me.

(Book figures, like what you are quoting above, rarely are hard and fast when applied to the real world.)

Bordercollie wrote:
I keep the rig connected to 120vac power, have a modern PD9245 converter charger that will not boil out electrolyte of house batteries. I have a Trik-L-Start device installed that keeps the starting battery up. Any charging device will deplete electrolyte levels so it is wise to check and replenish electrolytes with distilled water if/as needed. All wet cell lead-acid batteries self discharge over time so they need smart trickle chargers like Battery Minder to keep them fully charged but not over-charge

I do exactly the same, except I have the PD4655.