dead battery repeat. how do you check battery usage?

0okamiDigital · 06-07-2009, 02:31 PM

I left my lights on a few times and killed my battery, now it seems it does not want to hold charge or i have something draining it beyond belife.

is there a way to check how much power is being drawn off the battery while the jeep is off? I have a computer set up interfaced with the jeep's OEM computer and I kind of find it hard to belive that little scan tool is draining my battery in 8 hours to the point of no start. So, I need to figure out what device is pulling the most power off the battery while the jeep is off.

I've seen electricians put some device around wires and take measurements but im not familiar with such things... Any explanation welcome.

Right now im debating if to spend lots of money on an optima battery... but i really dont want to if i don't need it. The jeep will be having a 500/1 jl audio amp installed later this week. hmm...

**SirGCal** · 06-07-2009, 04:36 PM

IF you fully drained a conventional battery (even the 'red tops' like Optimas), they will never be 100% again. If you're winching a lot or forgetting to turn lights off like me, get a hybrid (part deep cycle, like the yellow/blue tops). They can be fully drained and recharged back to life. Hell, I left my Exide sitting with lights on for a MONTH (obviously died in a day... but had closed circuit for a month). Couldn't jump it. Took three days on a power charger to get it back up to snuff, but then it took right over and has worked flawlessly since. Conventional battery wouldn't even have had a chance in that situation.

But, if you have anything hooked up in the off-condition, it can kill the battery faster than you expect, especially if it's not a powerhouse battery. If you have a tiny 3A draw on a 30A/hour battery, it'll be to where it won't start easily in probably 5-6 hours, completely dead in 10. So don't think some tiny computer can't kill the battery... Default batteries in cars are starter batteries, not conventional 'run on this' batteries. They can put out tons of power for short bursts, but don't sustain small drains very long.

0okamiDigital · 06-07-2009, 04:48 PM

Thanks for the explanation. That helps me understand the situation better.

0okamiDigital · 06-09-2009, 09:25 PM

i went and bought a duralast Gold (item 561276 34-dlg at autozone) yellow battery... i forgot the specs but its an 8 year warranty.

Seems forgetting my lights totally killed that older battery. Jeep was shutting off every time i took the my foot off the gas and it was neutral. it would not hold a charge to even start back up. At least now i hope i dont have to worry for another 8 years.

I was going to get the Optima for just 30.00 more... but i figured 8 year Duralast warranty over 3 year optima felt far better.

**SirGCal** · 06-09-2009, 09:47 PM

Just don't kill it. Fully draining a conventional battery will kill it. It will never be 100% again (as you've learned). Generally for winching or big lights, etc. we use hybrid deepcycle batteries which can handle that type of abuse. (Even the red-top Optima is a conventional battery, the yellow and blue tops are not.) Your yellow top isn't the same as what we refer to when we mention yellow and blue tops... That's just a pretty battery is all. But from what I can see from their website for that part number, just a conventional battery.