Posted by Jim Anderson [162.158.75.121] on Saturday, August 26, 2017 at 23:10:23 :
In Reply to: How to Charge a Stone Dead Battery? posted by Greg Coffin [172.68.34.31] on Saturday, August 26, 2017 at 20:58:18 :
If you have a newer 'smart' battery charger this is what has worked for me (12 volt battery):
You need:
a charger supplying 15 amps or less.
a good 12V battery that has charged to 12.2V or better.
jumper cables (the bigger and shorter the better).
voltmeter
timer
Connect the good battery to the dead battery in parallel (+to+, - to -).
Hook the good battery to the charger.
Turn the charger on.
After an hour, check to see if the dead battery is warm or hot to the touch.
Warm is natural. Hot is not. Turn the charger off immediately if the dead battery is hot. Battery is scrap.
If the dead battery starts bubbling a lot or starts hissing, discontinue IMMEDIATELY. Battery is scrap.
Check often with voltmeter across dead battery terminals. It should reach 10.5V within 2 hours with a 10 amp charger.
Once at 10.5V, turn off charger and disconnect, disconnect batteries. Now put the charger on the dead battery and charge as normal.
Chances of a battery that is completely discharged holding a charge for very long is low.
jim
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