Fuse or circuit breaker for trunk mounted battery

[DKz Garage]

Hey guys..... looking for some input on protecting my starter wire from battery in trunk. My concern is not so much the positive cable chaffing and then shorting out, but rather, an accident that damages the car/cable causing it to short out and cause a fire. I see that DSE used a 400amp Mega fuse in the trunk as overcurrent protection. I have also seen a dual circuit breaker set up as well (200x2). I'm running an crate LT4, basically stock. Just wondering if the 400 AMPS will hold up on normal starting etc...??

Any input would be appreciated.

[Richard454]

I like these- Blue Sea marine grade fuse holders-several ways to mount- not that expensive.

As far as the fuse size? The fuse's only job is to blow before the wire melts- depending on the gauge of the wire being protected -is how you pick the max fuse amperage.
See the chart below-

I'm running two circuits- 1/0 for the starter/fans/electric power steering fuse at 300A then another 4 gauge circuit fused at 125A for the rest of the car- ECU/Fuel Pumps/Vintage Air/lights


196775

196776

196777

[slammed68]

400 amps is plenty.

I have a trunk mounted battery and run one of these https://www.amazon.com/gp/product/B075ZGR96T/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 on the battery terminal with only a 200A fuse. I also run a circuit breaker at the front of the car for the main power distribution (electric fans, headlights, fuse box, ect.)

[Jim Streib]

I run a 300A ANL fuse on my 1/0 copper wire from my trunk battery to the starter up front. Never had any issues. The reason for the ANL style was it was the only style out there 20+ years ago when I did the installation.

I'm running a stock style 1970's GM starter and the new high torque gear reduction starters actually draw less so do the homework and get the right cable size and then the proper sized fusing (or breaker).

I will add that with a trunk mounted battery put it in an enclosure that is vented to the exterior of the car or if the battery has vent nipples, put tubes on them and route these tubes to the exterior of the vehicle. Don't be mislead, if you are running even the AGM style batteries, they can vent explosive fumes.

Jim

[Just 1 More]

Great info and great topic, Thank you. Just ordered the BLU-2151

[TANKMASTERJ]

I'm using the 2151 at his advice also from the forum! In I'm running # 2 welding cable up over the rear tubs. Clamped. On the passenger side down into the rocker channel and to some nice heavy duty racetronix firewall pass thru connectors. Then # 2 ground to frame and starter. As well as from bulkhead to starter for hot. Then a #6 from bulkhead connector to alternator and my up front hot buss bar.

[Just 1 More]

I'm using the 2151 at his advice also from the forum!
Correct me if i'm thinking wrong, but, I'm thinking I can run my main battery cable (trunk mounted battery) off the 200amp and my Term X ecu off the 40amp

[Jim Streib]

The pictures I have show ratings on the holders. The single and the double have a max of 300A

https://static1.pt-content.com/images/pt/2021/09/24071024222_28dcf8dcd2_b-1.jpg

With a person running a single fuse holder then anything from a 300A and lower fuse would be fine but on the dual holder (unless I'm seeing this wrong) is the total of both fuses need to be 300A or less. One fuse could be a 200A and the other a 60A or less but one should not run dual 200A to where then the total would be 400A of fusing even though it's spread between two spots.

Just for reference is I've also seen this style holder for use with the same fuses:

https://static1.pt-content.com/images/noimg.gif

And protective cover for the assembly (and I think offered in either a left or right cable entry:

https://static1.pt-content.com/images/pt/2022/02/38161845014_b4bd079d02_z-1.jpg

Jim

[5ohphil]

Consider a circuit breaker instead of a fuse. Blue Sea systems makes some nice circuit breakers as well. No need to carry a spare as you would in a fused system.

[TANKMASTERJ]

Correct me if i'm thinking wrong, but, I'm thinking I can run my main battery cable (trunk mounted battery) off the 200amp and my Term X ecu off the 40amp

I don't see why not