It only took me 3 weeks.

I have two 12 volt batteries, and sometimes I want them to provide 24 volt, and sometimes 12 volt. Like this


In a previous discussion, someone helpfully suggested that I use a switch, to make it easy to change over.
I had several switches I considered, until I decided on this one



Is this what they call a 6-Pin Rocker Switch (ON-OFF-ON) ?
The two central pins are common, and they alternately connect to the poles on opposite ends, using the button on top.
( I hope the diagram makes sense :-/ )

Anyway, I think I have worked out how to switch between 12 and 24 volt output, using this switch.

If you are like me, and have nothing to do but mental gymnastics, can you work it out how its done ?

 

I think this would work. Switch top position is position 1, and down is position 2.

 

I think you have thethe red and green dots on the top battery the wrong way round. (I assume red is positive and green negative.)
Other than that I think it should work.

Les.

 

Yes, a graphical typo!

 

Had me going there for a while, but I changed the terminals as you said, and drew it out longhand to check.

It would appear to work fine.

Totally different to my solution, which I will upload in the next post.

Many thanks for contributing.

 

Using your excellent diagram layout, this is what I have come up with. It appears to use less wires.

If anyone can see problems, I would appreciate any advice

 

Here's a Circuit that's similar, maybe it could be useful to You ...........

Maybe I missed it,
but I don't remember seeing any reference as to how much
Current your project will be required handle.

The additional remote-control-Relay can be omitted, it was for a previous poster's request.
.
.
.

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Heeey. Thats very good of you, as I was potentially looking to have to use relays in the system in the future.
The actual working voltage is 24 volts DC, potentially 15 amps, so some types of switches might be problematic.
In the solution I came up with, the only current flow through the switch, at 24 volts is the "back leg", the join between the 2 batteries, and this can be a very short run, so I am hoping it will be ok.
The 12 volt configuration is so I can trickle charge the batteries with a 12 volt charger, so the current will be limited in that case.
I realise that DC runs have a few gotchas, so I will be doing more research and testing, for sure.
Many Thanks.

 

AH! Found it!

OK, I used a 3PDT switch. Below the switch is shown in both configurations:

I see others have already answered with a DPDT switch. Guess I was caught up in the complexity of the problem and not the simplicity of the solution.