The Stovebolt Site Forums The Shop Area The Electrical Bay 12 Volt accessories on 24 Volt System

I have an old army 6X6 with a 24 Volt system that uses 2 12 Volt batteries in series. I have a 12 Volt electic fuel pump installed acros from ground to the positive terminal of the battery that is grounded so it can operate on 12 Volt. I did this so I could get it running before I put a lot of money into it to see how much work it would require to get it running OK. To my surprise it appears that installing new spark plug wires and new plugs was the main cost of getting it running and it doesen't seem to be smoking now.(When I started it the first time it ran on 3 out of 6 smoked like heck and there was almost no compression on 2. Luckily 2 of the pushrods had kicked loose so it is now running great.)

Anyhow since it runs great now with the 12 Volt fuel pump I was wondering if anyone has had experience with center taping something off of the series batteries such as tail lights and fuel pumps and what this does to the batteries for charging. Will it boil the water out of the other battery while the generator is supplying to current to the accesories?

I work on motorcoaches and this a common system. If you tap 12 volts for very long, like you are doing now, it will kill that battery even with the truck running. You would need a battery equalizer to do the job ful time. We use Vanner brand equalizers that are rated by amp draw. 24 volt fuel pumps are not hard to find nor are light bulbs. Make a friend in the local bus garage, they aren't cheap but certainly less than converting to 12 volts. If you need help with 24 volt bulb numbers e-mail me

We ran them all the time with a tap of the center of the batteries for a radio and a beacon. Never had any problems, but there wasn't much current draw. And we didn't run them that often as they were fire trucks for a small rural department.

The best solution is a 24/12 power inverter of about the 18 amp size. Then you will have enough to run a radio CB recharge a cell phone or whatever else comes along. If you try and tap off of the battery it will cause that battery to die a slow agonizing death. It will also drive the charging system crazy, one battery will end up overcharged or one will be under charged. I work on 24/12 "stuff" daily, road graders and construction equipment for cities and counties who want to put their private band radios into their construction equipment. Let me know if I can help....Thanks Randy