Went to start my truck today and the batteries were dead. I did notice in the last couple of days that it was starting hard in the am but fine later on. It sat for over 30 hrs. and now it's dead. Took the batteries over to get tested and it took over an hour to do one. I didn't have the time today so I had him do only one and the load test was fine on it. Although when he hooked it up it was reading only 110 cca before charging. So I didn't get the other one hooked up, charged and tested.

Anyhow I didn't have this problem until after I installed the Predator. Is it related or do I just have a junk battery? And will one bad battery not allow the truck to start. I think not. What the heck is draining my batteries. Must be something because when I hooked them back up it seemed to spark a lot. Only thing I did different recently is the Predator on a 40hp tune.

gm batteries are junk. im sure its not predator related. i think the truck can start on one battery but only if its warm outside. put some new batteries in it and you should be fine,

It just depends. The oem batteries in mine lasted all of about 3 months. Replaced them with Optima red tops, got 10 years out of those, and just replaced em with yellow tops. Im not a fan of GMs oem batteries - the one in my vette is toast in less than 2 years. Long enough to be out of warranty for the btty but too short. There is an optima in its immediate future.

:exactly: ...time for battery replacement. Do 'em both; don't look back. I'm thinking of a color....pick one. :)

One bad battery could draw the other down, there hooked in parallel.

If your getting noticeable sparks with the key off, doors closed, no exterior lights coming on when you try to hook up then you may have a problem. You would probably only see a very small spark for keep alive circuits (less than 1/2 amp), security system, onstar, etc..

Get a multimeter Set on highest amp scale first and check draw from (only one battery hooked up) between the positive post and its cable. I don't know what draw you'll see on these new trucks, I would think more than 1 amp would be bad. Maybe someone here has checked and knows what the normal draw is.

It will go to the stealer tomorrow because it is under warranty. And the batteries say 7 year on them. We'll see what happens.

In regards to Catch007 and the amp test, I think the magic number is 75mA (0.075A) draw 5 mins after the key out and door closed. Look at the positive terminal of your battery and look for dried acid. There is a class action lawsuit against GM for leaky positive terminals. I received a new battery after 4 years on my S10.

gm batteries are junk. im sure its not predator related. i think the truck can start on one battery but only if its warm outside. put some new batteries in it and you should be fine,
Every GM vehicle I owned has had AC Delco batteries and everyone has been good. Never once had a problem with them. :)