AUX Battery Tray

 

GM Part Number: Battery tray - xx xx xx

GM Part Number: Battery hold down - xx xx xx

 

Not content with a single, stock battery to run all of the additional electronics systems, and AUX battery was called for. Looking under the hood of both the 2001 6L and 8L engine bays, there appeared to be no room for an AUX battery. The original thought was to mount a large Group 31 deep cycle on the outside frame rail under the passenger seat area. This mounting proved difficult in part due to the factory running boards. While investigating this, the realization set in that the 2001 diesel pickup has an AUX battery with a very similar under hood layout as the 6L and 8L 2001 Suburban. It looked like the space at the rear passenger side engine bay against the fender could hold an AUX battery. The 6L has an odd shaped bracket in that particular location, and the 8L has an air injector of some kind, presumably for emissions control. Turns out, the tray and hold down for the 8L emissions control air injector pump is in fact a GM AUX battery tray and battery hold down bracket. Since this is the same engine interior as the 6L, a home for a new Optima Yellow Top deep cycle battery was found. Too bad about the 8L…perhaps the air injector can be removed and the hoses plugged.

Optima Yellow Top - $170

Hellroaring 75300 Combiner/Isolator - $150

http://www.optimabatteries.com

http://www.hellroaring.com

 

For the AUX battery, an Optima Yellow Top deep cycle was used. To attach it to the system, a Hellroaring Technologies 75300 battery isolator/combiner was installed. The Hellroaring configuration used was the Basic Auxiliary Battery Isolation setup due to the desire to have fully separate battery systems, while still retaining the ability of taking full advantage of the 75300 features at a future time. The disadvantage to this setup is the limitation of pulling at most 75 amps sustained between the two batteries. This includes the alternator to AUX battery power draw since the alternator is attached to the main battery. The temperature of the engine compartment gets plenty hot, so the use of recommended wire gauge is highly advisable during installation. This setup uses a pair of 6 AUG cables from the main battery junction box near the alternator and runs them up and along the back of the engine compartment to the Hellroaring combiner.

The combiner is mounted to the rear panel next to the AUX battery. A short 2 AUG cable is run from the combiner to the AUX battery. A pair of 6 AUG cables are run from the combiner and AUX battery negative terminal back across the rear of the compartment. From there, the cables are run through a 75-amp breaker (positive only), down under the body next to the front left wheel well, along the frame and into the cabin through an existing rubber grommet. This existing grommet is used to run a single plastic tube of unknown, but probably very important, role. The ends of the power feed cables and grommet need to be lubed to allow the two 6 AUG power cables to be forced up through the existing hole in the grommet.

Once the wires are inside the cab, they are routed out from under the driver's side floorboard, under the carpet (but above the insulator material), to the doorsill. At this point it is a simple matter of running the cables to their final resting place inside the third row, driver's side storage tray (just behind the third row side drink holder). This run is about 30 feet round trip (up the positive and back down the negative side), and with 6 AUG wires, the 75 amp breaker in the system is about right for this size and length of cable run. To use a full sized power inverter (Prosine 1800 for example) a direct battery connection with 1 AUG cable would be desired.

Before setting up this AUX system, additional stereo equipment was installed. This installation took place after work, in the dark, necessitating the need to keep the interior lights on for hours at a time. This caused the main battery to run down the first time. Once the additional stereo gear was installed, a problem was found which drained the main battery for the second time. This was a bad drain as the Suburban was left unused with a 400ma draw for a week, leaving the main battery pretty much a lost cause. At this point, the main could not hold a charge as well as it could when it was new (only 3 months old), but it still worked. Then came drain number three. Another late night running wires with the interior lights on. The main is now an Optima Yellow Top, making a pair under the hood. From this lesson, it may be a good idea to run the interior lights off of the newly installed AUX battery.

A note about electrical components

 

http://www.westmarine.com

 

Most of the electrical supplies used are marine grade materials, including all wiring. Marine grade wire and components are a bit more expensive than the stuff obtained from the local HW supply, but the quality and longevity are far superior.

email:SubRider

10/16/01