Inverter fuses

[Paulm]

I'm getting ready to connect up my 600w/1000w sine wave inverter. I'd like to add an external fuse to avoid replaceing the internal one.It has 40a x2 fuses inside. For the external one I was going to use a ANL 80a fuse. What do you guys use? I think it's a safe thing to use a fuse on my 575ah battery bank. That's alot of current if there's a short!

[Volvo farmer]

I don't know the designation but you can get big whoppin' DC fuses and holders for cheap at NAPA. I think I got a 200A fuse and holder for $15 or so. I guess they use them on big rigs(?) but they're way way cheaper than so-called "solar energy" fuses. It's best to go in when they're slow and find a friendly parts guy to look in the catalogs for you, My local store is pretty big and these were not in-stock items.

[ghurd]

I use a smaller external fuse then the internal fuse.

Fuses like these are not exactally accurate. If the internal ones will blow at 79 amps, and the external one blows at 81 amps, you will be tearing it apart anyway.

Maybe a 60 or 75 amp external fuse? Just a little more than what you really need.

G-

[Paulm]

How about a circuit breaker to save on fuse replacement ?

[ghurd]

I did it once or twice with cheap DC breakers.

Even with a lighter breaker, the fuses would blow before the breaker kicked.

Honestly, I don't use many 'big' fuses, mostly the blade auto type.

You can get the blade auto fuses in a monster size that goes 40A to maybe 100A.

G-

[Nando]

First:

The new fuse has to be lower carrying current capability, so if you have 40 X 2 the new ones need to be 30 amps X 2.

A breaker should operate better than a fuse BUT you need to learn how to use them for proper operation.

Use the breaker data sheet to determine the trip point to be prior the regular fuse, considering the time required to trip either one, also check the fuse operating curve ( temperature and current ).

Regards

Nando