Fuse Between Alt n Battery - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Dodge68charger · 11-13-2019, 03:22 AM

Cant Find a Definite Answer. Some Say Yes, Others Say Dont Bother

If So What Size Fuse For a 140 Amp Alternator?

Its a One Wire. Not Sure How To Wire It. Wire From Alternator To Battery or Can It Be Wired To The Starter Solenoid?

Can The Fuse Box Be Powered From The Starter Solenoid?

Is The Painless 30700 Kit An Idea...

Just Dont Want a Fire.. Thanks Guys
Posted via Mobile Device

rpmerf · 11-13-2019, 09:09 AM

I have a 30 amp fuse right after the battery. The only time it ever popped was when my voltage regulator died. I do have a mostly factory truck, so even with lights, radio, and HVAC running, I should be around 30 amps. With the factory setup, the power will pull from the generator instead of the battery, since the generator is located between the battery and the fuse block. The only thing going to the battery should be for charging the battery.

I have considered putting a big fuse right after the alternator. Some food for thought. Say your alternator wire hits the header and burns through. The fuse on the battery should pop right away. Once you shut the engine down, the alternator is no longer supplying power.

This does also depend on exactly how you have it wired. If you have the alt on the passenger's side, wired to the starter, then I would be much more inclined to have a fuse. I believe OEMs use a fuseable link between the alternator and battery. I'm pretty sure that's how it is on my 97 Suburban with a 140 amp alternator.

**HO455** · 11-13-2019, 03:11 PM

What you should install is a fusable link not a fuse. The OE's don't use fuses. They will protect you from short circuits but won't arbitrarily fail (as will fuses do) and cause damage to the alternator. Here is a link to my repair thread look to post 469 for more information on fusable links.

http://67-72chevytrucks.com/vboard/s...698377&page=19

This link will help you on how to correctly wire your new alternator. Plus tons of other good information.

http://www.madelectrical.com/electri...evymain1.shtml

Hope this helps.

weq92f · 11-13-2019, 03:28 PM

.
FWIW, I'm going with a fusible link to protect mine. Alt goes to bus bar via 6ga cable. I'm going to install about 6 inches of 8ga fusible link wire between the alt and the bus bar.

Hth,

-klb

11-13-2019, 03:22 AM	#1
Dodge68charger Registered User Join Date: Jul 2014 Location: Washington Posts: 532	Fuse Between Alt n Battery Cant Find a Definite Answer. Some Say Yes, Others Say Dont Bother If So What Size Fuse For a 140 Amp Alternator? Its a One Wire. Not Sure How To Wire It. Wire From Alternator To Battery or Can It Be Wired To The Starter Solenoid? Can The Fuse Box Be Powered From The Starter Solenoid? Is The Painless 30700 Kit An Idea... Just Dont Want a Fire.. Thanks Guys Posted via Mobile Device

11-13-2019, 09:09 AM	#2
rpmerf Registered User Join Date: Feb 2011 Location: Parkville, MD Posts: 1,024	Re: Fuse Between Alt n Battery I have a 30 amp fuse right after the battery. The only time it ever popped was when my voltage regulator died. I do have a mostly factory truck, so even with lights, radio, and HVAC running, I should be around 30 amps. With the factory setup, the power will pull from the generator instead of the battery, since the generator is located between the battery and the fuse block. The only thing going to the battery should be for charging the battery. I have considered putting a big fuse right after the alternator. Some food for thought. Say your alternator wire hits the header and burns through. The fuse on the battery should pop right away. Once you shut the engine down, the alternator is no longer supplying power. This does also depend on exactly how you have it wired. If you have the alt on the passenger's side, wired to the starter, then I would be much more inclined to have a fuse. I believe OEMs use a fuseable link between the alternator and battery. I'm pretty sure that's how it is on my 97 Suburban with a 140 amp alternator. __________________ 1970 C20 Custom Camper - 350, TH350 1997 GMC Suburban 1994 Acura Integra GSR 1987 Dodge Daytona Shelby Z

11-13-2019, 03:11 PM	#3
HO455 Post Whore Join Date: Feb 2016 Location: Portland Oregon Posts: 11,268	Re: Fuse Between Alt n Battery What you should install is a fusable link not a fuse. The OE's don't use fuses. They will protect you from short circuits but won't arbitrarily fail (as will fuses do) and cause damage to the alternator. Here is a link to my repair thread look to post 469 for more information on fusable links. http://67-72chevytrucks.com/vboard/s...698377&page=19 This link will help you on how to correctly wire your new alternator. Plus tons of other good information. http://www.madelectrical.com/electri...evymain1.shtml Hope this helps. __________________ Thanks to Bob and Jeanie and everyone else at Superior Performance for all their great help. RIP Bob Parks. 1967 Burban (the WMB),1988 S10 Blazer (the Stink10 II),1969 GTO (the Goat), 1970 Javelin, 1952 F2 Ford OHC six 4X4, 29 Model A, 72 Firebird (the DBP Bird). 85 Alfa Romeo If it breaks I didn't want it in the first place The WMB repair thread http://67-72chevytrucks.com/vboard/s...d.php?t=698377

11-13-2019, 03:28 PM	#4
weq92f Registered User Join Date: Oct 2016 Location: Dallas Texas Posts: 3,151	Re: Fuse Between Alt n Battery . FWIW, I'm going with a fusible link to protect mine. Alt goes to bus bar via 6ga cable. I'm going to install about 6 inches of 8ga fusible link wire between the alt and the bus bar. Hth, -klb __________________ 67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold



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