Mixing different volatage batteries

x2 on battery bank switch. There is getting a job done, and getting a job done right. The battery bank switch is the right way to do it.

Only thing I might add is an inline catastrophic fuse or circuit breaker on the lines so if a dead short does happen, you are out a fuse, not your wiring or your entire rig.

Sloop Smitten wrote:
Here is how I wired mine with a selectable switch. That way you can run them all at once or isolate as desired.

Looks like something I might try. What kind of switch is that? Bad thing about 6's is if one goes you are out of 12v power all together.

Here is how I wired mine with a selectable switch. That way you can run them all at once or isolate as desired.

Mess with your jumper cables. It doesn't get any easier than that...

So it'll work okay, provided it's wired correctly, as smkettner states/shows.

"Optimum" charging configuration sounds like it'd be done as separate banks.

Don't know that I want to mess with the switch so I'll have to think this one over. Maybe wait till after my next trip and see how I make out boondocking with just the 6's.

Appreciate the help.

Older discussions here:
(Don't worry, 8 year old information is still valid)

Add 12v to 2 6v 2006
12 and 2 6v 2010

Padlin wrote:


Or this

Connect the load to the left hand 6v+ for better results.

NOTHING should connect to the 6v series jumper between the 6v batteries.

I would actually connect the load to the 6v pair and let the 12v tag along.

BB_TX wrote:

sch911 wrote:
This way would be better:

Much much better unless you want to destroy your batteries.

Correct

Padlin wrote:


Or this

This will not work properly. You're only giving the load 6V. It is only very marginally better than your first drawing, which had the batteries shorted out. This one probably wouldn't blow up, or start a fire right away, but it won't work and could well destroy a battery or your converter/charger over time

The 12V battery is, broadly speaking, equivalent to two 6V batteries in series. The 12V battery has six cells in series internally; the 6V batteries each have three cells in series. The main difficulties alluded to by other posters are due to significant differences in cell structure between the two batteries.

Based on the pictures you're posting, I would suggest that you have someone else (with a decent knowledge of things electrical/electronic) check out your actual wiring before you connect things up. It's easy enough to cross yourself up when you're quite clear on what needs to be done, and having only a fuzzy understanding of things doesn't make it any easier.