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Battery continually going bad

I’ve got a 2002 Chevy Avalanche, which for the past few years has been going through batteries about every nine months. The battery will start having issues starting the truck, will die overnight, etc. It always jumpstarts OK, it just won’t hold a charge. I’ve had the truck checked out several times by different mechanics, and no one can find a reason for the batteries dying. I did some research, and I think I may have a reason for the batteries going bad. While this was my primary vehicle for quite a while, for the last three or four years has been relegated to second car status, and only gets driven once, maybe twice a week. From my research, if the battery doesn’t get charged enough during drives, it can cause the battery to go bad over time, and since I’m only driving it about 30 miles a week, that sounds like it’s plausible to me.

So my question is how often I need to drive the truck in order to keep the battery properly charged and healthy - if I make several short trips in to town, is that worse than one longer trip? Any ideas would be great.


Do you leave it unattended for extended periods of time? Even when you don’t drive it, there is some draw from the battery if you have things like an alarm installed.
Lead acid batteries don’t like to be discharged, sitting around for a while without being recharged. It causes the battery becomes weak to eventually not being capable of holding a good charge.
You could get a ‘float charger’ that basically consists of a ‘wall wart’ transformer with two clip leads. It trickles the battery with a low current, just like the car would if you’re driving it continuously. You hook that onto the battery when you know you won’t touch the vehicle for a while.
Sears sells them for about $20 or so.

If it is not possible to plug in a battery charger or tender, having a battery disconnect switch put in might be useful. Most people I know wit motorhomes have them.

FWIW, I drive my '93 Explorer even less than you do: 20 mi/wk. and the last battery I replaced on 9/99 lasted 9 yrs and 7 mos. before I decided to replace it pre-emptively. My current battery has been working fine since 4/09 so it has been going strong for 4 yr 6 mos. So anyway, in my case it doesn’t appear that little driving shortens battery life. Your car being much newer than mine might have more stay-alive type current drawing power when the car is not in use. If you are so inclined perhaps you should try to troubleshoot it yourself. With a multimeter in current mode you could attach the probes to break the battery circuit and see if there is an inordinately large draw when the car is not being used. Good luck!

Yes, they’ve all been under warranty so far, so it’s more an annoyance than costly. And the threat of it not starting at some random location. I don’t leave it too unattended - it sits in the driveway, until I need it - but it definitely just sits there. The trickle charger is a good idea, I may have to go that route. For about $20 you really can’t beat it.

Thanks for all the advice!