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[Dave Underwood]

I had already thought the lighter put out 12 volts so you could plug it in directly. That is then legal as it is portable equipment. You might need a splitter if you want to power more items, but I think those are widely available.

Otherwise you might want to build something and get some form of approval. If that is the case, I can make two suggestions, 1) find a volage regulator that will handle the voltage/amperage requirements or 2) find a DC to DC converter. That would allow you to take 24 volts down to 12 volts off a fuse or breaker.

The DC to DC converter is more efficient and lower heat output.

Regards - Dave