Mega fuse

[deltarat]

I am installing a Painless wiring harness and a 140 amp one wire alternator. The instructions say to add a 125 amp or larger fuse between the alternator and the battery, that is not provided, when using a large alternator. The parts house only goes up to 80 amp and that is as large a maxi fuse that is listed in their book. Do I need anything larger than the 80,and if so, where do I get one? I am using a #6 wire from the alternator to the fuse and or battery.

 

[NicksTrix]

you don't want to blow the fuse when your alt is cranking towards it's high end.
waytek sells them as do many other electrical suppliers.

 

[Fathom]

I would try to find a breaker.
If it blows you can re-set it.
You don't have to carry replacements.

Good Luck!

Brian

 

[73stallion]

if you need it right away, do you have a truck stop near by? when i worked at TA we carried them, and almost all trucks had them on board. don't know where to tell you to get a housing for one though.

i got mine from BC and i carry a spare.
bottom of the page; http://www.bcbroncos.com/store/index.php?cPath=26_88

 

[Fathom]

;D Breaker;D

http://www.bcbroncos.com/store/product_info.php?cPath=26_88&products_id=563

 

[casadejohnson]

You can also find them at a good car stereo shop. Don't forget to get the holder.

 

[Broncobowsher]

Fuse must be larger then alternators capacity.
If it is smaller, and you run the battery down a touch (lights on for a while, crank on a non-starting engine, little engine off winching, etc), then start the engine. The alternator will go to full output to charge the battery. What happens when you push 140 amps through a 125 amp fuse? well it will blow. What happens when you pull all the load off an alternator that is putting out full power? it spikes itself and blows the diodes in about half a revolution (fast idle that is about 1/6000 of a second; 1000 engine RPM, 3:1 ratio step up). You never want to let the alternator make more power then the fuse can handle. Fuse is there for something real bad, dead short type of thing.

Sourcing a proper fuse/curcuit breaker is a different story.

 

[trailpsycho]

You can find this stuff on McMaster-Carr. I ordered mine and a couple of spares. The car stereo places didnt have the amperage I needed and were very $$. Autoparts stores didnt offer enough amperage in their mega-fuses. I typically get things the very next day from McMaster-Carr without paying for next day service. Prices are fair, quality is excellent.

 

[tasker]

Right from the Napa website-have other amp ratings as well



Part: BK 7821138
Product Line: Balkamp
Features & Benefits
AMG Fuses Designed For 100 To 300 Amp Applications, Interrupt Rating 1,000 Amp At 32 VDC, AMG Fuses Meet The Needs Of Selected Late Model Vehicles w/ Heavy Electrical System Loads, The Fuses Protect Main Circuitry From The Engine, AMG Bolt On Fuse Ty
Attributes
Fuse Amp Rating : 150 Amp
Fuse Style Name : AMG MEGA Bolt On Fuse
Voltage : 32 VDC

 

[W650Mike]

Golf cart shops generally have high Amp fuses much like Tasker has shown. The BC Bronco re-set breaker shown above looks like a great alternative.

 

[deltarat]

Right from the Napa website-have other amp ratings as well



Part: BK 7821138
Product Line: Balkamp
Features & Benefits
AMG Fuses Designed For 100 To 300 Amp Applications, Interrupt Rating 1,000 Amp At 32 VDC, AMG Fuses Meet The Needs Of Selected Late Model Vehicles w/ Heavy Electrical System Loads, The Fuses Protect Main Circuitry From The Engine, AMG Bolt On Fuse Ty
Attributes
Fuse Amp Rating : 150 Amp
Fuse Style Name : AMG MEGA Bolt On Fuse
Voltage : 32 VDC

The NAPA guy found the fuse, but did not find a holder for it.

 

[bluebronco69]

just ordered one off of ebay, it will hole 0,2 and 4 gauge wire, and you can specify the fuse, just search ANL fuse #
and put in whatever size you want, i went with 150amp but they have 140 175 200 etc.

 

[bluebronco69]

oh and it ran 15$ shipped. including a water proof fuse holder

 

[tasker]

Part: BK 7821143
Product Line: Balkamp
Features & Benefits
Thermal Plastic Holder For AMG Type Fuse Rated From 100 To 300 A, Compatible w/ Center Mounted Bases
Attributes
Amp Rating : 250 Amp
Product Application : Fuse Block
Style Name : MEGA Fuseholder
Package Contents : Fuse Block