Owl

Am doing some wiring on my 2010 JKU. It appears that there's a fuse-link at the end of the alternator output conductor at the battery. The alternator output conductor appears to be #6 (a guess) red in color with a yellow stripe. At the battery it appears to have a fuse link (green wire): Photo below.

Does anyone know what the maximum alternator output is? What the value of the fuse-link is?


Thanks for any help.

Mr.T

A bit late for a reply, but it's either a 140 or 160 amp alternator -- They used both.

Owl

Thanks Mr. T. Did some research and found the answer on-line. Did not find out what the value of the fuse link was / is. Anybody?

Mr.T

The "rule of thumb" is that the fusible link wire gauge is 4 numbers higher than the wire it is protecting. For example, if the red wire in the pic is #6, the fusible link should be #10. In any case, if that green fusible link wire is original equipment -- That's the wire gauge to replace with.

Haven't seen fuse links rated in ampacity, that would be interesting table to find. A fusible link is like a very-slow blow fuse or similar with a long inverse time delay. Considerable over-current is allowed if the time duration is short enough.

Owl

Mr. T.

Thanks for the reply, and sorry for the "very" late reply to you and an overdue thanks!! Anyway, your rule of thumb makes sense. It's my understanding that the smaller gauge conductor, used as a fuse link, will melt (this is where it gets messy) prior to the larger gauge conductor overheating and melting. I found the following link that provides a reference to actual alternator output conductor sizes:

https://alternatorparts.com/wire-size-chart.html

Let's say I install a new, high output, alternator (use 240 amps as a reference). Based on the chart from the link, I'd replace the existing alternator output conductor with a #2 AWG conductor (less than 5' from alternator to battery), then install a #6 fuse link (based on your rule of thumb). However, it appears that the actual "fuse link" conductors stop at #8 AWG (the conductors apparently have a special insulation that will not catch fire if the overheated conductor melts).

https://www.whiteproducts.com/fusible-faqs.shtml

I'm guessing that the theory behind the fuse link application is to allow more "time" to pass at a high current situation, where a standard fuse would open much more quickly. Anyway, enough rambling on my part. Just wanted to thank you for the reply.

Owl