Posted by Steve G on March 19, 19100 at 05:52:37:
I'm adding dual batteries to my '94 K1500. I just ordered the left-hand side Battery tray(for diesel Subs) from the dealer ($37). The plan is to use the second battery for the video setup and the interior lights so they can run down the aux battery instead of the main battery when the engine is off. I have three questions:
1. Looks like the charcoal canister is in the way of the second battery tray. Doesn't look too hard to relocate it. Has anyone installed the left-hand side battery tray and have you had to move the canister?
2. Should I use a deep-discharge battery? Any disadvantages to using one?
3. It seems the usual way to hook up the dual batteries is thru an isolator, which appears to be just two diodes. This prevents one battery from feeding the other. Is there a significant voltage drop thru the isolator (usually diodes drop about 0.7 Volts)? Also, if I run down the aux battery and then start the engine, the aux battery will require a high charge rate. Will this cause the main battery (which may be fully charged) to overcharge?
Painless Performance makes a great microprocessor-controlled multi-battery control system which monitors up to three batteries and keeps them charged. It also allows you to select batteries for starting and you can connect up to all three in parallel in case of emergency. There is no isolator as the control provides the necessary switching to keep everything charged. Unfortunately it cost $250.
Thanks for the help
Steve G