I need to put a fuseable link between the alternator and the starter but can't find one at the autozone near my house. The alternator is a 100 amp so don't I need at least a 125 amp link. Any ideas? Thanks RUSTY

 

I ended up using one of the big fuses typically used for stereo equipment.
here is a holder and two 125amp fuses.. like what I did for my 160amp output alternator

http://cgi.ebay.com/FUSE-HOLDER-ANL-...3%3A1|294%3A50

Sam

 

That's basically the same way I have my electrical system protected. Those maxi-fuses are nice.

 

Hi Rusty,

Is this a new alternator? If so you might think about contacting the manufacturer to see if they have a Fusable link (fuse in the holder) to install. Remember, electricity doesn't push, it pulls. So you want to be sure to put in a fuse block in for all your electrical items to protect them as well.

Just between us....if you get something that's going to short and pull 100 amps, you are going to be arc welding stuff. Even if you turn on everything (heater, wipers, lights, stereo, electric fan, fog lights, horns, electric fuel pump, etc) electrical on your truck (on a 12 volt system) you shouldn't be pulling any more than 40-50 amps MAX.

 

while I agree, I can't imagine anything upstream of the starter that would pull that much individual power. (my electric fans go direct bypassing this circuit).

But this protection is for when the alternator gets stuck in full output mode, and can fry the wire (as I understand it). It is 'strongly' recommended in ALL installations as far I have seen. and its always the alternator failing is the issue.. not some device shorting. Ezwire expressly says it will void the warranty if you forget the fusible link/fuse.

Sam

 

I got a 50 inline fuse with the ez kit. But if the alternator is putting out more than 50 amp the 50 will blow am I right? RUSTY

 

AutoZone near me has fusible links, but probably not the kind you were expecting. It looks like a fuseholder, and has a replaceable element. Sure sounds like a fuse, doesn't it?! I think they are what modern cars use, but since I avoid those kinds of cars, I couldn't tell you.

NAPA near me sells the traditional looking fusible links, you might try them.

 

Rusty,
The purpose of the fusible link is to protect the wire. It is typically the next smaller wire gauge protected with extra high temp insulation so that if the current draw is too great, the link burns, not the rest of the feeder wire.
You need to know the gauge of the wire running from your alternator to the starter so you can get the correct fusible link. You can make one yourself if you can solder a short length (3-6") of the next smaller wire guage and cover it with several layers of high temp heat shrink. Not the cheap stuff but something with a continuous rating of 150C minimum. Be sure to put it right at the alternator and don't bundle it with anything else until several inches after the link.
Good Luck!

 

The difficulty for me was my 160amp output requires a 2 gauge wire. that means a 4 gauge FL.. largest I could find was 10 gauge.

Sam

 

I think there is more to it than gauge; I am pretty sure they are also a different alloy, and are engineered to melt at a specific current within a specific time. Just using a smaller gauge you'd do a lot of damage before it broke contact.

Check here: http://www.madelectrical.com/catalog/fusible-link.shtml

 

I will stand corrected, Ross's reference material quote

"Only a serious short will cause a Fusible Link to burn'

Julie.. my apologies..

sam

 

can someone tell me why you need to run a fused wire between the alternator and the starter????Why a wire between the the them????

 

You don't and you shouldn't. What you might be thinking about is the wiring between the Alternator and the Starter Solenoid.

In the Ford wiring scheme, the initial main distribution point for power (both coming from the battery and from the charging system) was the "battery" terminal of the starter solenoid - the battery is treated as a peripheral.

In a GM type system, the battery positive post is used as the main junction for power input and distribution.

In most GM designs, the support components such as starter solenoids, voltage regulators for alternators, etc are contained internally (or attached to the component itself).

Ford made all those seperate, removeable, service items as a cost savings measure.

And Sam, you were right with what you said, I think we were thinking the same thing but expressing it differently. The only casualty that is serious enough to break the fusable link is if the alternator clicks into full output because there is a direct short (probably on the charging circuit wire) and that will turn that short into an arc welder-100 amps is A LOT of electricity. The fusable link will disconnect the alternator from the short and not only will save the wiring, but the alternator itself (because with an open ground it is producing at maximum output which it normally can do only for a very short time - remember when shorted the alternator is outputting at it's RATED MAXIMUM output, not the MAXIMUM SUSTAINABLE output it is designed to operate to under normal conditions)

 

Thanks I thought this was something new. The only time the alternator would put out full output would be if the field wire became shorted to power. The fuse link would be at the starter solenoid not up at the alternator.

 

in my 460 implementation the starter solenoid is at the starter like in the GM design. so the FL/fuse is in the wire/cable from the alternator to the solenoid (at the starter).. The battery main lead is also connected there.

Sam