Charging a dead Battery

N

Nick4

New Member
Hey guys, I have a less than one year old battery that I let sit for a few weeks on the bike without disconnecting. I always disconnect it when it is going to sit, but I forgot. Anyhow, the battery is showing too low voltage for the "smart charger" to charge it.

Any tricks to either fool the smart charger or up the voltage on the battery?

Thanks
 
Trick the charger, hook up the battery and the use jumper cables from the battery to a car battery. Charger will see more voltage.

If you can get the bike started run it for 5 minutes at a high idle, that should charge the battery enough for the charger to take over.
 
Hey thanks, tried the jumper cables, it worked. But the bike battery won't hold a charge. I've left it hooked up to the battery tender for 2 days now and it is still hovering at 5 volts. If I take the tender off, it starts to drop fairly quick.

Guessing the battery is just wasted. Guess I'll not get a cheap one from oreillys next time.
 
I buy batteries from Walmart and autozone, so long as you don't let them run flat often they will last years. I got 4 years out of the battery I bought at Walmart for my 360.

The trick is NOT to let these light duty batteries run down. They are not built for it and will die very quickly. Not like a car battery that has 4 times the capacity.

Best deal is to keep them charged and figure out why a they drain in a bike.
 
A 12V battery showing 5V is a trash battery I am sorry to say.
If a battery is reading below 10.5 its usually junk.
 
Yeah seems like you've got a dead cell. Internal short. I've used the jumper cables before and it works on a low battery, but not damaged already.
 
Hey thanks guys. I left it one a few more days and nothing. Such a pain in the ass.

The bike is brand new to me, previous guy claimed new battery. Finally got the bike to start and it ran pretty rough. Rebuilt the carbs, new points, and was trying to start her up to set the timing and nothing. Oh well. New battery here I come.

Thanks again
 
I just "revived" a dead battery the other day. It was in a 250 scooter that had been sitting for 12 months or so. I used a car battery charger (3 amp, old skool type) and periodically charged it for a few hours a day for a week or so. It started at 5v, then each day crept up until it was holding 12.5v steady.

Sometimes you can get lucky.
 
I've revived larger batteries quite a few times, hit them with a larger amp charger for an hour and then back it down let it cool off and then do it again, rinse and repeat. Its called desulfation, basically you are trying to break up the crap on the plates with HEAT which causes the stuff to fall off and either settle to the bottom or be cooked out. Have to keep them full of water while you do it or you can screw them up again.

They are never the same battery once you do but they will last a little longer. I tried to revive my 360 battery that way recently only too find that it was toast. Got to looking for a new one and found out I had been running the WRONG size the entire last 3 years. Nice new CORRECT battery and man does it spin that starter now. ;D
 
Be very careful when charging sealed or gel batteries. They have a different charge rate than lead acid. Your charger may have maintenance free or regular settings. Same amps are put out but their not the same frequency range. I know, I'll find out more and let you know. Sealed batteries can be boiled real easy, even at 10 amps. That trashes them for good, lead acids leak all over the place need constant upkeep, but will take abusive charge rates.
 
Scooter trash said:
Sealed batteries can be boiled real easy, even at 10 amps.
Click to expand...

I hope you meant 1 AMP. :o 10 amps on any Battery for much more than a few minutes will cause damage.
 
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