My wife and I are going to be out of town for 2 months, and one of our cars will be staying home and not getting much driving. We have a Black and Decker Battery Maintainer that we were considering using to keep the battery fully charged. Unfortunately, we don't have an enclosed garage: we can park our car under our back porch, so it won't be fully exposed to the elements, but it's not hermetically sealed either (and this is Virginia during the summer, so some heavy rains are unavoidable). We don't have an actual all-weather cover for the car, but could cover the charger with a tarp.

How seriously do we need to take the warnings in the manual to not use the charger in the rain? How bad would it be to have the charger on the ground?

The other option would be just letting the battery sit, and hooking up the charger when we get back, which I have to admit sounds more reasonable to me, but I know could lead to some battery damage.

  • trickle charger outside protected from the elements. Commented May 28, 2016 at 21:58

2 Answers 2


I don't know the exact model of the trickle charger, but would suggest against using it and getting an actual battery tender instead. The difference is, the trickle charger will continue to charge, but at a really slow rate. This means, you can over charge the battery and cause damage to the battery with it. A battery tender will keep the battery in tip top shape, only charging it as is needed to keep the full charge. Using the tender will prevent boiling your battery.

Also, if you go this route, the tender is small enough you can enclose it under the hood of your vehicle, with just the extension cord sticking out from under the vehicle or wherever. You can usually completely shut your hood without issue. This allows everything to be completely contained without fear of someone coming along and messing with it.

Being here in VA myself, you can pick up a cheap tender at many places (Sears, AutoZone, Advance Auto, Harbor Freight, Walmart) for around $20. It's a cheap investment for any battery you are going to leave sitting for a long period of time.

As far as the warnings on your current charger, if it won't fit under the hood as suggested, I'd highly recommend not using it at any rate. Running it on the ground is not going to be a good thing either, due to the possibility of rain as suggested. If it fries, it could cause serious problems on your property. With you begin gone, you may come back to a house which isn't there anymore (extreme example, yes, but entirely possible).


Disconnect the battery negative. You'll lose radio presets and ECU learning, but nothing else. I don't know what vehicle you have so it's hard to judge how difficult this will be, but I doubt much. 10mm wrench and 5 minutes. A one-beer job.

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