The Corvette sat a while and the battery has gone dead. Putting my charger on it doesn't seem to do anything. Do I need a different charger or is there something I need to be doing?
The Corvette sat a while and the battery has gone dead. Putting my charger on it doesn't seem to do anything. Do I need a different charger or is there something I need to be doing?
Many "smart" chargers will not charge an AGM battery that has gone too low, something about the resistance properties of it makes them think that it is a battery with a shorted cell and they shut down for safety reasons. You can sometimes get around this by hooking up another battery in parallel with the AGM.
See "how to resuscitate a deeply discharged battery" here: https://www.optimabatteries.com/charging
I ended up buying a modern charger for my AGM.
In reply to codrus (Forum Supporter) :
Prius cars run an AGM 12 volt battery. Those are my only experience, but I buy Priuii cheap and they usually have dead 12V AGM batteries.
I've always been successful in bringing them back to life using this method:
Good to go again, note some really flat batteries have required the above procedure to be performed multiple times. But I have a 100% success rate on the last 8 batteries I've done this to.
Edit to add: The AGM battery usually gets "hot" while charging. The first one I did, I was very concerned, but that appears to be normal for these. I just use a simple charger. I'll take a picture of it and add later tonight.
In reply to Indy - Guy :
I've done something similar, but simpler. I just put the spare lead acid battery on the floor and connected it to the charger, then ran jumpers from the LA to the AGM in the car. I did leave the hood open, but I didn't notice any real heat buildup.
Both batteries were fully charged in about 3 days or so.
+ 1 to what Duke wrote. I did the same and it worked fine.
eastpark said:+ 1 to what Duke wrote. I did the same and it worked fine.
2+...I've been successful doing this too.
the newest CTEK charger that i purchased had an "AGM" mode and i put the charger into AGM mode and leave it plugged into the cigarette lighter on my car which has an AGM battery and it works fine.
https://www.amazon.com/CTEK-40-206-5-0-12-Battery-Charger/dp/B00CD44RQO/ref=asc_df_B00CD44RQO/?tag=hyprod-20&linkCode=df0&hvadid=312844081654&hvpos=&hvnetw=g&hvrand=12144841581412696668&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9021527&hvtargid=pla-461267516060&psc=1
In reply to ClearWaterMS :
When I first read your post all I could picture was that meme sketch of the V8 with the exhaust routed directly into the intake.
Of course, I can't find the image when I need it.
In reply to Indy - Guy :
I'll have to try that, know how long you should expect that to work? Just replaced my Miata battery which was 6 years old after trickle charger didn't bring it back.
I've done it by the method described above. Connect it to a known good battery, connect charger to the good battery. 1-12 hours later, It is good to go.
How long can a AGM battery be dead and still bring it back to enough to start a car ?
I sometimes see used dead ones at repair shops that I can get for a couple 6 packs :)
californiamilleghia said:How long can a AGM battery be dead and still bring it back to enough to start a car ?
I sometimes see used dead ones at repair shops that I can get for a couple 6 packs :)
The one that was 6 years old and dead for an entire winter lasted about 6 more months. I revived it again after it sat for 2 weeks, it lasted 2 more weeks then had to be kept on a trickle charger for anything longer than 36ish hours. I sold the car advertised with a known dead battery at that point.
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