Can I connect 6 and 12 volt batteries together?

[zensius]

I'm going to be driving my Ex for a long time at idle or thereabouts. That means the alternator won't be charging. An overdrive pulley only increases 33% which still isn't enough. So I was thinking of increasing capacity. I have two 6 volt rv batteries that I could connect in series to make 12 volts and then connect those in parallel to the 12 volt battery. Dumb idea?

 

[Turdle]

I'm going to be driving my Ex for a long time at idle or thereabouts. That means the alternator won't be charging. An overdrive pulley only increases 33% which still isn't enough. So I was thinking of increasing capacity. I have two 6 volt rv batteries that I could connect in series to make 12 volts and then connect those in parallel to the 12 volt battery. Dumb idea?

The thing that scares me is that the 6v batteries will do the most and develop more heat during the charge cycle. You will be combining a voltage dividing circuit with a current divider-
this is ok if you are certain of the internal resistance of all components. If one of the 6v batteries breaks down internally, (shorts) all of the charge current will go there and BOOM might happen.

With all the people riding on that art car, and considering the atmosphere-competition I would not risk it.

Someone else my chime in with better advice. This is merely my opinion.

 

[Maniak]

Sort of.. Using big 6v batteries like that is done in some golf carts. You can get some pretty big capacity if you do that (run 6v batteries in series and parallel).

BUT,

When you run the batteries in series/parallel you do need to make sure all the batteries are the same age and same brand and capacity as they are now a "bank" of batteries.

What your suggesting is to mix them (two 6v and a 12v). Thats normally a no-no. Just like running two 12v batteries in parallel that aren't the same (age or brand or size)

~Mark

 

[deamon3]

In the long term I would agree. But in the short term , they'll probably be fine

 

[Turdle]

In the long term I would agree. But in the short term , they'll probably be fine

This is going to be in the middle of the desert. The truck will be loaded with people, and already a dangerous, crazy situation


and it will be a crowded --ehem, party atmosphere. There may be a crowd of people hanging around this thing. Medical care will be scarce.

I think I need to be there as a safety supervisor. Got extra tickets?