Fuse for rechargeable pp9

[Refugee]

That is an inductive load on DC.
Certainly a very bad idea.

[Danndad]

                   

Pamphonica’s idea of the resettable polyfuse is a really good idea but I couldn’t decide how to go about mounting such a thing as they are quite big (16x11mm)?

I soldered one of the fuses I bought on the outside of the dummy battery but thought it looked vulnerable like this so I thought I would refine it a bit.

I ended up putting the fuse on the inside of the bamboo, soldering it up and putting some heatshrink over it just to smarten it up a bit.

[Doodlebug]

Slightly OT. I take 5v power from a laptop USB for some
equipment. I always fuse that well down.
Does anyone know what would happen though if this
USB supply were ever shorted out?
Do USB 5v supplies have internal shut down protection?

[Nick]

Pamphonica’s idea of the resettable polyfuse is a really good idea but I couldn’t decide how to go about mounting such a thing as they are quite big (16x11mm)?

I soldered one of the fuses I bought on the outside of the dummy battery but thought it looked vulnerable like this so I thought I would refine it a bit.

I ended up putting the fuse on the inside of the bamboo, soldering it up and putting some heatshrink over it just to smarten it up a bit.

Polyfuses are small - a 500mA one is around 5mm is diameter and I'm sure you can get smaller ones. Have a look at the usual suppliers (Farnell/RS/Rapid etc.)

[Alistair D]

There are various styles of AAA to AA battery adaptors on Ebay. With a little ingenuity one of them could be made into a fuseholder.

This is one example

https://www.ebay.co.uk/itm/154874010349?...Sw5Z5bgheQ

Al