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Winter float charge of batteries out in the cold weather

Winter float charge of batteries out in the cold weather

(OP)
Pretend I have:

- GMC motorhome with 2 separate batts
- 3pc 36v golf cart type machines
- 3pc antique cars with 12v batts
- 5pc farm equipment with 12v batts
- 1pc OLD farm tractor with 6v battery
- 1pc AGM starter 7kw whole house inverter generator
- 3-4 misc small 12v gel cells of 7-15aH capacity

These need to survive over winter storage. Best way??

The motorhome has state of the art charger system (float plus every 28 days smack plates with charge current to reduce sulphide build up) with separate outputs for each battery.

I have for 100 years(?) used #12 romex run throughout barns from 13.50v DC ham power supply (100amp?) - it goes to most 12v batts in parallel - so many years ago that I do not remember which ones have series diodes in the circuit. It normally keeps 12v car batts good for 6-7 years before needing replacement. Poor old Sears has been replacing one of these, my lifetime guaranteed battery, since 1973. One old car for sure has series diode, and its battery is going on 10 years old now with car driven once every year or so. I KNOW this is too low a voltage, especially in the cold. I believe room temp 13.5 is good float level, and at say 40F it goes up to to around 14.1v for same effect...

I have improperly ignored the 12v "lawn and garden" small batts or put one at a time on a 10a batt charger every other month or so if I remembered - and they usually fail every year because of this - but now that I have MORE time available near retirement, I would like to save these too.

My 24 million dollar question: HOW?

I have a spare GMC charger unit with 28 day cycle... I probably should bare minimum replace my ham 13.5 supply with that? And just put all batts in parallel on my #12 romex string?

I recently had to buy [don't you??] 6pc Harbor Freight float chargers when they went on sale for $ 4.99 each (don't get me going on that - they vary from 13.1 to 14.2v output so are NFG as is [I can change pcb VR1 component to pot and adjust properly but am inherently lazy]...

My ideas of best solution(s) appear to be:

0) Just use the cheap $4.99 float chargers (I can add diode to drop output voltage .5v if needed) on the garden tractor cheap batteries and leave all else as is.

1) Better to just use my 13.5 ham supply [2pc 2meter radios on it] AND PUT all batts in parallel (today, I have 3 antique cars in parallel and the batts last 6-7yrs each)?

2) Swap ham 13.5 supply for spare GMC smart unit and put ALL batts in parallel?

3) Adjust these Harbor Freight float chargers to output correct voltage for batt type and use individual ones?

4) Better idea?

Thank you.

www.KilroyWasHere<dot>com

RE: Winter float charge of batteries out in the cold weather

All batts in parallel doesn't sound like a real good idea.
Any batts in parallel doesn't sound like a real good idea.
I'd be inclined to use the cheap float chargers, adjusted as you like,
_and_ cover the vehicles
_and_ keep a light bulb on under the vehicle to moderate the winter temperature.

Mike Halloran
Pembroke Pines, FL, USA

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