In-Vehicle Long term Battery Charging

GregP

Well-known member
I will be storing my diesel outdoors this winter and won't be driving it for a few months or so. I changed the oil, filled fuel tank and added conditioner to the tank, but am trying to decide what to do with the batteries. I want to leave the batteries in the truck and am planning on connecting a float charger to them to maintain the charge (and hopefully the life) of the batteries while not in use. Can I connect the charger leads to one battery and be assured that both batteries will be charged and maintained equally, or should I connect one lead of the charger to the neg post of battery #1 and the other lead to the pos post of battery #2. The unit will be stored in Northern Ontario (Canada) so I am not expecting it to have to endure a hot winter. Thanks for any advice.
 

mlpeloquin

Well-known member
If the batteries are connected in parallel, then just across one battery should be fine. Also it should be a battery tender so that it floats when the battery is fully charged. This insures they are not over charged unlike a trickle charger. If the battery's voltage drops the tender will turn on again and top the charge off again automatically. You don't need an expensive one. https://www.amazon.com/Battery-Tend...=1511925870&sr=8-3&keywords=battery+tender+jr will do. 0.75A should more than take care of the parasitic draw on a vehicle parked shut off and still maintain the batteries.

You made me querious about at what temperature a battery will freeze. Fully charged -70F and at 12V discharged 32F.
https://www.cars.com/articles/2014/02/can-a-car-battery-freeze/
 

GregP

Well-known member
Thanks Bill, Marc and Jim for the helpful advice. In the past, I would have pulled the battery from the truck and stored it inside with periodic charging to maintain it. Now, with all the computerized functions happening under the hood, I am reluctant to disconnect for a long period of time. I have a good battery tender/charger that will maintain a float charge so I will give that a try. Since we haven't had the 70 below temps here (up to now) I don't think I need to worry about battery freezing as long as they are charged. Next winter, we are hoping to be wintering somewhere warmer, so battery freeze-up shouldn't be an issue.
 
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