I have 2006 Tahoe LT. Over the past 18 months, I have gone through 3 gel batteries. The batteries will last for about 6 months then they are completely dead. More recently, my wife has informed me that some days the voltage gauge jumps around a bit when she starts the car and then settles around 12 volts (I haven't seen this yet). We have tested the alternator and starter and they are all testing good. I am about to replace all the fuses (in case there is a bad one that is causing a drain).

I am curious if anyone has experienced similar issues and may be able to share with me how they resolved it.

Thanks!

 

A bad fuse will not cause a drain on the battery. They are either good or bad. Overcharging from the alternator will kill a battery after a while as will excessive heat. A short in the electrical system could also hurt a battery.