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NEED HELP WITH FUSE SIZES (last one was posted under wrong category)

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I have a 350 amp apex alternator, a front battery delete with sky-high terminals, and a 40ah lithium battery in the back next to the amp. Im running dual 1/0 for my big 3 and from my battery delete terminals to my lithium battery in the back. My question is what size fuse do I use for my alternator positive to the battery delete terminal? My next question is What size fuse do I use from my battery delete terminal to the 40ah lithium battery in the back? (Keep in mind my big3 which also includes alt positive to battery terminal positive is 2 runs of 1/0. My battery delete terminal to 40ah lithium is also two runs of 1/0, its about 25 feet from battery delete terminal to battery.) 
Thanks guys! :)


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Generally speaking, the fuse is there to protect the wire.  You can run fuses lower than the ampacity rating for the wire, but you shouldn't go higher.  You mentioned that your terminals are Sky-High, what 1/0 do you have?  Is it OFC (and if it isn't OFC you should definitely upgrade to OFC)


KnuKonceptz 1/0 OFC (which is a little oversized) is rated at 375 amps.


I would suggest running a 350A fuse for each 1/0 run.  Make sure each run/cable is fused rather than using a bus bar that is fused (unless it's only fused at 350A which would defeat the purpose of the double runs).


That should protect the wire and ensure maximum amperage.


Hope this helps!



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Just to add to what @Arthur79said, I'll just copy and paste what I wrote on the other post lol


So, assuming you're using OFC cable, 1/0 OFC cable is usually rated around 350 amps safely. That's also pretty conservative for some brands. That being said, between the alt, and the battery, fuse to the rating of the cable. So each run should receive a 350a- 400a fuse. 

The 2 places you should fuse are as close as you can get to your alternator, and a close as you can get to your lithium. Then all the cable between the 2 fuse points will be protected, including the battery delete spot. 

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2011 Chevy Silverado under construction

My build log here. Check it out! 


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