Need switch to control power and load circuits in robot

[JohnGa]

Hello,
In my RC Lawn mower project, I am using a Sabertooth 2×32 controller. The power is coming from 2 12V SLA batteries wired in series. I want to use a DPDT, ON-(OFF)-ON switch. The switch will allow me to turn OFF both load and power circuits. In one ON position, it will allow me to use the charging port. In another ON position, the load circuit (motors via sabertooth) will be enabled. What kind of a switch do I need to buy? What should the V/Amp ratings on this switch be?

[SuperDroid]

Hi JohnGa,
Let me see if I understand this correctly.

–Switch up–
Power form the battery to the sabertooth and any other components

–Switch middle–
Cut power to all components

–Switch down–
No power to any components, but will allow you to charge the batteries.

Let me know if i am not correct.
If you are trying to charge the batteries, you don’t need to cut power to the rest of the robot. If you put the charging wires before the switch, when the switch is off, you won’t be powering the robot, but you will be able to charge the batteries. Just remember to put a fuse on the charging wire just in case there is a short.

[JohnGa]

Hello,
I want to use an XLR charging port. This is my first project involving power, and don’t want to fry expensive electronics/batteries. Can you please give me a quick and dirty schematic for what you recommended? If I were to go that route, what kind of a switch do I need? What power ratings should the switch have? Where should the fuses go?

Thanks.

[SuperDroid]

Hi John,
I have attached a basic schematic for that setup. Please make sure that you are using the correct wire gauge for the project, and Also please verify that the positive and negative pins on the charger are in the right orientation when wiring the XLR charging plug. Verification can be done by plugging in the charger and CAREFULLY using a voltmeter to determine which pin is the positive pin.

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[JohnGa]

Thank you so much for the clear wiring diagram. This gives me a lot of confidence to proceed. One more question: What power ratings should the switch in the load circuit have?

[SuperDroid]

The switch should be able to handle a bit over the maximum current that you expect. Our 2 position toggle switch can handle 25A per pole. Often times we run the power wires to both the poles just to be safe.

[Author]

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