Metal box with battery protection device

[anbonn]

Aluminum I create my own mods to my house. The dc-dc controller contains protection circuitry, but it may damage wiring, short-circuit.
I want to build additional protection (PTC fuse ..)
Does anyone have a tried and tested, simple solution?

 

[Rocketman]

A PTC fuse (resettable) sometimes climbs in resistance after the first trip, but it keeps working. A Pico size fuse, with leads, oR a small automobile type fuse (you can solder to the tabs) might work. TO protect the controller, a fast acting fuse might be best.

 

[jimbalny]

That's really effin cool! Good designing!

The OKR/T-6 switching regulator has overcurrent and over-temperature protection and seeing as it looks like you're using two batteries in series it'd be perfect. Plus it could work out to be a lot smaller than the regulator you're using now. only thing is it's a little more complicated to wire.