I think one of my batteries is dying. Today the voltage gauge stayed almost exactly in the middle between 8 and 14 instead of on the good side of 14. Once I got home I checked the voltage. With the engine off both registered 12.51 volts. With the engine running the driver side battery dropped to 12.14 and the passenger side battery was at 14+.

Does this sound like the driver side battery has gone bad? I'm going to see if I can get them tested tomorrow.

Thanks,
William Crawley

 

did you disconnect the cables when checking with the engine off?
Try cleaning the cable from the pass battery to the drivers battery and check both grounds...

 

Load test them.

 

tryNto is correct. If both batteries are connected in parallel (normal), there is no way you should have that much voltage drop between the two batteries unless the junction between the two cables is corroded. Same thing happened to mine and in fact I received the check engine light for low voltage. My cables showed no sign of corrosion, but I measured a huge voltage difference where the passenger cable joins the driver-side battery. I disconnected, hit it with a wire brush and re-connected, and the problem has been gone for ~18 months.

The situation is actually a little dangerous because the alternator first connects to the passenger side battery, but the feedback to the alternator seems to come from the driver side along with the main load (including the starter). Once my inter-connecting cable corroded, my driver battery drained to ~8.5 volts, thus the feedback told the alternator to charge like mad. So the passenger battery was measuring a ~17 volt charge when running and getting real hot. Luckily I didn't have to drive far to get home and find this problem with the volt meter.

Good luck with yours.

 

Turns out it may have been a little of both. One of the cables may have been a little loose and one of the batteries was dying.

Thanks,
William Crawley