OK, someone explain it to me--------

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DesertRat

DesertRat

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I am at the stage wiring my engine bay with the MAD ampmeter bypass that it is time to put the fusable links to the starter relay. The MAD document calls for a 14GA link from the alternator to the starter relay and a 16GA link from the starter relay to the dual wires running through the drilled out bulkhead connector. Being an electrician I am trained to fuse these deals, not have a wire that intentionally melts down! I am thinking of using a standard spade fuse block (double) and fuse both circuits with a 40A in from alternator and a 30A out to dash power. (I am installing Rob's headlight relay kit) So, I can go either way and unless someone can give me a damn good reason to install melting wires, I will fuse it. Please advise!
Thanks all and enjoy the Super Bowl!----------DR----------:coffee2:
 
Pretty much exactly what I did, but used self resetting breakers.
After three years, not one problem with it anywhere and I used 30 amp in both places in spite of some saying the one in the charging system should be bigger to handle the alternator to battery loads. (like a 50 or 60)
If I ever needed a bigger amp breaker I'm sure it would have presented by now.
 
Wow, thanks dude, I was looking at them yesterday. The boat I ocean fish on has those, I diagnosed a bad one on the high seas last summer-------------O:)
 
How long do the fusible links take to melt? Maybe a slow-blow breaker (do they make those?) so it can handle some mild spikes.
 
DesertRat said:
Wow, thanks dude, I was looking at them yesterday. The boat I ocean fish on has those, I diagnosed a bad one on the high seas last summer-------------O:)
Click to expand...

I think generally, the reliability of marine style equipment blows the doors off standard off the shelf automotive stuff.
Having years and years of marine experience with all it's trials end errors it kind of made sense to use things that have proven themselves in that environment to make auto stuff more reliable and functional when we can.

(ex Ocean boat owner, fisher and scuba diver here) and NOTHING sucks worse than having something break or quit working out there.

Screw fusable links. :D
That was a 40 year old solution.
 
You are thinking wrong. Fuse links "were" a last ditch measure, and did not always work. They are in effect a fuse, just "not as precision." 40A might not be a large enough fuse, how big is your alternator? Fuse in the alternator line has to carry full tilt aternator current. Also be aware of DErating fuses and breakers "for temperature" if they are located in the what-can-be very hot summer engine compartment.
 
Fuses being thermal devices, there is always a time lag. For standard fuses, it takes many minutes to blow at rated current. An example here is a Maxi fuse; it takes almost 2 minutes for a 20A rated one to blow with 30A amps current. So, for transient charging conditions, that probably explains why a lower rated one survives. You just can't get that much precision in a fuse....

[ame]http://www.littelfuse.com/~/media/automotive/catalogs/littelfuse_fuseology.pdf[/ame]
 
nm9stheham said:
Fuses being thermal devices, there is always a time lag. For standard fuses, it takes many minutes to blow at rated current. An example here is a Maxi fuse; it takes almost 2 minutes for a 20A rated one to blow with 30A amps current. So, for transient charging conditions, that probably explains why a lower rated one survives. You just can't get that much precision in a fuse....

http://www.littelfuse.com/~/media/automotive/catalogs/littelfuse_fuseology.pdf
Click to expand...

LOL, my point was as bad as fuses may be, "links" are even worse.
 
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