Keeping car battery charged over winter

September 15, 2014 7:26 PM

Is a trickle charger the same as a 2 amp charger?

I keep my car stored for the winter. I am not at the location where the care is stored nor is there power in the shelter where the car sits. What is the best (and safest) way to make sure the battery is fully charged come spring? I own a 2/10 amp Schumacher battery charger.

Last year I just left the car sit all winter. In the spring, I put the charger on the battery overnight and in the morning the car started. However, a couple of weeks later, I accidentally left my lights on for about 20 minutes. The battery died and never recovered after that and needed to be replaced.

posted by pmaxwell to Travel & Transportation (4 answers total)

Best answer: What you want is a float charger. The Battery Tender Jr. is a good choice for not much money. There are off brands for less, Harbor Freight sells one for $10.00, sometimes less on sale. These aren't very good for charging a dead battery but are exactly what you need to maintain a battery in a car that is parked over the winter. This write up is explains the difference between float charge and trickle charge.
posted by Grumpy old geek at 7:39 PM on September 15, 2014 [1 favorite]

I cannot explain the chemistry involved, but I know it has something to do with corrosion/disintegration within the battery as it is sitting and losing charge. As you learned - you can charge it up again, but its life is dramatically shortened by letting it sit all winter without running/charging.

To answer your question: No, they are not the same action. A trickle charger keeps the battery topped up and keeps it from going bad, whereas the one-time charge after a long time of sitting around is almost like a false positive. It will work for a bit, but the battery has already been irreversibly damaged from not using it.

(My knowledge comes from years of owning a motorcycle) What I do, over winter, if I can't store it next to a power source, is I remove the battery and take it home and trickle charge it there.
posted by zyxwvut at 7:40 PM on September 15, 2014

OP says there's no power in the shelter, so a plug-in charger won't work. If you can get sunlight on the car, and if your cigarette lighter works when the key is off, you can use a solar float charger. Or you could remove the battery during the winter and keep it trickle-charged at home.
posted by Johnny Wallflower at 8:55 PM on September 15, 2014 [1 favorite]

Response by poster: Thanks GOG.
I'll prob opt for the Battery Tender Jr since it will be left unattended in my basement for a few months and I wouldn't trust the cheap HF version.
posted by pmaxwell at 8:56 PM on September 15, 2014