Quote:
Originally Posted by kennyfj40
Bill,
Got the bracket for the upgrade to the 150 amp alternator, looks great by the way, thanks. I have been reading through the posts about the wiring and have a question for you electrical types. I saw that you recommend using a fuse between the alternator and battery and it should be 20% greater than the amps being pushed through the wire. I see some people using the 150 amp fuse or breaker. I am going with the 150amp alt, so do I need a 180amp fuse? I am having trouble finding one in that size seems they go from 150 then jump to 200. Will the 150 work or is it safe to jump up to the 200amp fuse?
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Thank you.
Maybe an electrical type can correct me if I'm wrong but I will take a shot at it.
The fuse is there to protect the wire and the components. If you are using a 4 gauge wire as many are, I think the wire is rated for 125-150 amps maximum around 4-5 feet long. So based on that wire size and length a 200 amp fuse might be a bit much.
I’m pretty sure these Mega fuses have a slow blow component.
I just looked and on the back of the fuse package there is a scale that shows how much over current protection and for how long. I looked at a couple of different Mega size fuses I have and they both have this same slow blow percentage rating scale. So a 150 amp fuse with this slow blow feature should be able to handle a current surge or spike for a short time without blowing. In looking it says the fuses will take 130 percent over current for 10 minutes. So a 150 amp could take 195 amps for 10 minutes before blowing. For what its worth, 200 percent for 3 1/2 seconds.
Here is an example with a little information. Lol, I don’t know who would buy a used fuse but I guess it takes all kinds.
The
company does show they make a 175 amp if you scroll down a bit but don’t know about the availability here.
sdnative - It's good to hear you got the bad boy in there.
Bill