Truck battery question

[JimDRIl]

I hadn't started my old 89 Toyota truck in maybe 6 months and she wouldn't start. The battery must of had a little juice in her, the dome light was lit, but not enough to crank her. Anyhow I unhooked the positive cable which came off with no problem but when I tried to unscrew the ground clamp the bolt was rusted solid. would not budge an inch. I noticed the clamp was not tight on the post, I could lift it right off. I brought the battery home and hooked up the charger, battery is three years old, a 72 month batt. Now I don't know how long I should leave the charger on... I'm afraid of over charging if the clamp was just loose. The charger is a Schumacher 10 AMP quick charge. I miss the old style batteries with the caps. How long would you leave the charger on?

 

[Geo-TH,In]

A good charger will shut off automatically

 

[Charles in Aus.]

Look to see what the amp hour rating of the battery is , this will give you a rough indication of its capacity . 40 amp hours is about average for a mid sized car's battery . Your charger has a 10 amp capacity , so in the ' theoretical' world from empty it should take four hours to completely charge a 40 amp hour battery . Of course there are many other variables but if you have a battery that's most likely at half capacity then two hours at ten amps should come close . Things to watch for are electrolyte bubbling in old style batteries or a soft hissing sound from sealed ones . As soon as that happens turn off the charger .

 

[MarkB_MI]

After sitting idle for six months, your battery is probably sulfated and no good.

If you have a voltmeter, monitor the voltage as you charge it. Don't let the charge voltage get much over 15 volts.

 

[pinball]

my chargers all have a meter on them. it will tell you how much charge the battery is taken. once it gets down right a zero I stop the charger.

 

[guido]

Hello Jimdril,

That 10amp charger won't hurt your battery. Charge the battery and monitor the voltage. If voltage climbs to 15 volts within a few minutes the battery is bad. It should take two to three hours for the voltage to be around 14 to 14.5 volts. If the battery takes that long to reach that voltage, it should start the car, provided all else is well. Once the battery comes off the charger, and rested for 15 minutes or so, check the voltage. Anything above 12.4 V @ 60* it should be strong enough to start the engine. A fully charged battery will have a voltage of 12.6 V @ 80* F.

Guido.