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I have an outdoor car that working from home I don't drive more than once a week or so with a once a month longer trip. I'm not interested in going out for a thirty minute drive once a week to keep my battery topped up; and if I can get away with it, I'd rather not have to take the battery out in freezing temps to put it on a trickle charger in a warm environment. I'm thinking about just getting a battery charger with ring terminals and leaving the SAE connection easily available in the windshield cowl to plug in.

Thing I don't know is -- batteries don't discharge well in the cold (thus starting problems), but that's at very high amperage. Would this affect a trickle chargers operation in any way? The trickle charger itself would be in an outdoor outlet enclosure so I imagine some of the heat from the wall-wart would help it stay warmer, but I don't know about the battery which is just under the vehicles hood. Maybe if I got one of those foam/fabric battery jackets?

Sidney
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Car batteries will charge just fine in freezing temperatures as long as they are not deeply discharged and frozen.

A properly designed trickle charger / battery maintainer adjusts the charging voltage slightly depending on ambient temperature, so you want the maintainer to be exposed to the same temperature as the car battery. Keeping the maintainer artificially warm defeats the temperature compensation.

The compensation raises the charging voltage on a 12V battery by 18mV per degree Celsius drop in temperature below 25C. So going from a nice fall day down to a bone chilling zero degrees F, the maintainer raises the battery charging voltage by about 0.77 volts. It's important to allow this adjustment to take place to ensure a full charge.

Some battery maintainers are totally sealed waterproof / weatherproof and may be installed under the hood near the battery. I've used those and they've worked great for me. Just don't forget to unplug it before you drive away.

MTA
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