My work vehicle is a 2015 Chevy Tahoe. It has the dual battery system. My understanding is the battery next to the passenger side firewall is the "starting" battery the other is an accessory battery. When I got up to go to work a few days ago I noticed the starter lagging. Weak battery. I notified the shop I was asked did it start. I said yes they said keep driving it. Plam to forehead! So this morning it failed to start. I had to jump it. The Tahoe started right up. The battery is not cooked just week. I called the shop I was told I had to schedule an appointment. WTF! Its just a bad battery. So anyway I've got a few different battery chargers. Can I hook a battery charger to the "starting" battery or do I need to disconnect the negative cable? There appears to be an isolator, does the isolated automatically connect the batteries soon as the key is turned or is it voltage regulated? I'm not familiar with this sett up. I don't want to have to jump it again in the morning. However I'm also tempted to just leave it be and call my boss at 4 am and tell him my ride won't start. Maybe the battery will get replaced faster.

 

Nevermind I thought this was a factory installed option. If dual batteries is a factory option this one is not. The aux battery dropped to 6v. The starting battery was left on the CTeck charger last night. When you turn the key it connects both batteries via the isolator. Flipped the key and the starting battery immediately started dropping voltage. So I disconnected the auxIliary battery and was able to start the Tahoe. Told my boss he said don't go to the shop they take to long want an appointment ect. He got clearance to just buy the batteries with the vehicle card. Problem solved.