OK, I have a dual battery setup on my 98 Suburban. I previously had a 40 amp Ignition fuse that had a direct short. Got that taken care of and noticed only one of my batteries are being charged by the alternator. The passenger side battery is the battery that is connected to the starter and is the one that isn't charging. I checked the diagram in my Haynes manual and don't see a relay or isolator in my installation? My drivers side battery is charging at 14 volts, so the alternator is working. The truck starts fine right now too. Thanks in advance for any suggestions.

 

Update on my charging issue. Drove the suburban to get gas today. Alternator gauge was reading around 10 volts while driving. Didn’t dare shut it off, thought it might not start again. Got home and checked both batteries with my meter. They were at 12.41 volts. Disconnected both battery cables and Disconnected the cable going to the Alternator. Cleaned all the connections and reinstalled everything. Started truck and all is charging now. I think I had a few loose connections that were causing the one battery not to charge?

 

Absolutely possible, especially if it’s the side terminals with insulator sleeves.

Those “stubby” bolts are far too easy to overtighten & strip, and even when you do tighten them correctly, they will work loose over time.

Remove the insulator sleeves and coat the terminals (cable & battery) with a battery terminal protectant. Throw away the sleeves - they obviously don’t help prevent corrosion.

Replace the stubby bolts with a 3/8x16x1 - thread a hex nut onto the bolt - up to the head - before putting it through the cable and threading into battery. Tighten bolt down snug, then hold the cable against the battery while threading the nut down tight - just snug with an open ended wrench.

Spray more protectant on the bolts/cables after installation and recheck bolt tightness after a few hundred miles. Grab the cable just below the bolt and try to move it side-to-side - no movement means they’ll most likely stay tight until you want to disconnect them again - however it’s good practice to recheck them at every oil change.

 

Awesome advice! I was leery of those sleeves and your advice confirms that! I think those stubby bolts are garbage as well! I am going to take your advice and do it like you suggested! Thanks again, very much appreciated!