alternator? batteries?

[timelessconstructionllc]

I have 3 halogens mouted to the bottom side of my toolbox lid. Last night I left them on accidentally and this morning my truck was stone dead. I had a buddy jump me and truck ran fine I idled it for ten nor 15 min then drove it about ten miles then idles another ten min then drove about 20 miles. On the 20 mile trip, not thinking, I turned on the AC. My voltmeter went way down to the point my truck would hardly run then turned off the AC bug it went to bogging down etc. I have two 6 month old interstate batteries. Shouldn't the alternator have charged them. Right now I'm on the side of the road waiting for a jump. Any advice would be greatly appreciated.

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[timelessconstructionllc]

ok. i got it jumped again and everything was fine. this time i jumped both batteries and it kept a charge for about 30 miles of driving but now i have shut it off and when i did the voltmeter was really low.

 

[B.G. Smith]

If the alternator is working it should have charged the batteries some in that length of time. Of course you could have a bad battery. Before you run it agaion I would disconnect one battery and then chack the voltage in each battery to see if thay are near the same voltage. If they are , then start the truck and check the voltage again, the alternator should maintain about 13. 8 to 14. 5 volts with the head lights and AC on and the truck idling. When starting(jumping) a dead battery vehicle do not race the engine when the engine first starts, it can put a tremendous load on the alternator. bg

 

[timelessconstructionllc]

both batteries read twelve volts, with it sitting shut off. both batteries are right at six months old so they are still under warranty. i guess i'll be going to the battery store in the morning.

 

[RobertHiltz]

Clean and tighten all battery cables on both ends. Then charge the batteries. If the problem still exists load test each battery before doing further diagnostics.

 

[steved]

both batteries read twelve volts, with it sitting shut off. both batteries are right at six months old so they are still under warranty. i guess i'll be going to the battery store in the morning.

Did you disconnect the batteries from each other when you tested them??



I would say that you probably didn't give them long enough to fully charge... or the deep discharge caused one or both of the batteries to fail.