A method of mounting an aux battery

[GBurton]

For all of you who want to add one or two additional batteries to power your audio equipment, radios, winch or whatever. GM produces a full size diesel van, Express or Savana. The second battery is located on the outside of the frame rail under the drivers seat. It is in it's own removable battery tray that is bolted to the outside of the frame rail. The GM part number is 15017904 and it is from the 2000 (and other years?) Express or Savana van.

You can not mount it on the drivers side on our trucks because of the emergency brake cable on the outside of the frame rail and fuel lines on the inside. However, the passenger side frame rail is clear.

Look under your truck at the frame on the passenger side. As the frame comes down from the engine it is spliced into the main frame. You can tell because of a size change in the frame. What I did was mount the first battery box as far back as I could and just in front of the body mount. The second box will be mounted a few inches in from of the first and it will cover the splice. I positioned the bottom of the battery box even with the bottom of the frame.
GM used some type of threaded inserts but I just used bolts and nuts to mount the box.

The box comes with 4 mounting holes, 2 on each side. The top holes are "key hole" shaped slots to allow you to hang the box assembly over the bolts during installation. The bottom bolt holes are oval slots for alignment.

When you are ready to mount the battery you will install it in the battery tray, clamp it in place and then lift both the tray and the battery into position using the "key hole" shaped slots. You can then install the lower bolts and tighten all 4 bolts. When you order the battery tray be sure to order the battery hold down clamp and metric bolt. It is the same clamp that GM has been using for years.

It's a bit hard to service the battery but I don't know where else to install an extra battery or batteries in our trucks.
WARNING, be very careful if your battery has side post terminals! I am using sealed, non serviceable batteries that have both top and side posts. I am leaving the side post covers in place and using the top posts.
Comments or questions are welcome. At this time I am not able to post pictures.

George

[Bmacs]

Thanks for the info George!!

I've been racking my brain trying to figure out how to fit more battery in this truck. Good find! I'll probably be throwing some optimas in the holders.

73 and keep up the good work!!

[GBurton]

Bmacs

Yep, that way I can leave my APRS tracker powered up 24/7 without being concerned about running down the vehicle starting batteries.

Here is how I set my system up. I used a device called "Charge Guard" that is normally used to control the power to a two-way radio. It is rated at around 30 amps. Since us Hams sometimes have equipment that draws more than 30 amps, I used the Charge Guard to control a continous duty, high current relay. They are sold at RV suppliers to parallel batteries.

The Charge Guard will disconnect after a set time limit or if the battery voltage goes below a setpoint. It closes when it see the output from the alternator. It is looking for the slight amount of high frequency ripple that is there when the alternator is working. There is one other time that it will close and that is if you depress the emergency override switch. The idea is to give you about 10 minutes of radio operation if you really need it, to call for help.

I used large wire to connect everything together. That way if you happen to run down your starting batteries all you need to do is, remember the emergency override switch? Just push it to close the high current relay and start your vehicle. Just like having built in jumper cables. Been there, done that and it would have been a long walk down the hill go get help. [img]smile.gif[/img]

When the engine is running, all of the batteries are connected in parallel giving you lots of battery plus alternator power to run a winch, high power inverter or any other large load. When you shut the engine off I have the timer on my system is set to disconnect the two battery systems 15 minutes after the alternator shuts down. After that time, all of your extra loads that are connected to the extra batteries are isolated from your starting batteries.

George