Fuse for trunk battery

[badazz81z28]

Do any of you PT trunk battery users have a fuse at the battery terminal? If so, what are you using?

Thanks

[1989GTA]

I do. It is a Littlefuse Mega but I forget the amperage. Maybe 300? I have other fuses to, like between the alternator and the distribution block. Here is a link.

http://www.delcity.net/store/MEGA%C2...FUhufgod6lgCbg

[slofut]

I'm thinking about putting a constant duty solenoid at the battery with a 3 amp or so fuse in parallel. Wired to the ign switch ...it's on when the switch is on, but the big ass cable is disconnected when the switch is off ...like at night, while I'm asleep.

[badazz81z28]

I'm thinking about putting a constant duty solenoid at the battery with a 3 amp or so fuse in parallel. Wired to the ign switch ...it's on when the switch is on, but the big ass cable is disconnected when the switch is off ...like at night, while I'm asleep.

I have seen that all over the net, but too many wires to try and route through my cab. I think the chance of my Quick Car cable chafing through it's shielding is not likely, but by chance a fuse would blow if it did. A fuse just seems like a similar effective method without all the additional wires.

[obengston]

I don't have a fuse, but I do have a remote (keychain) selonoid mounted on the battery box so I can just hit the button and it kills all power coming from the battery (except the alarm). When I'm ready to go for a ride I just hit the key chain and all power is instantly back on. The only thing it kills the power to the radio so no channels stay programmed. I could easily fix that by wiring like I did my alarm, but really don't listen to the radio just the iPod that connects to the radio.

[slofut]

I have seen that all over the net, but too many wires to try and route through my cab. I think the chance of my Quick Car cable chafing through it's shielding is not likely, but by chance a fuse would blow if it did. A fuse just seems like a similar effective method without all the additional wires.

You'd have to use a large fuse like you said, and I've been tossing this back and forth on my car between a fuse or solenoid without a final decision. I've seen a lot of cars burned up because of wiring issues so I'm with you on fusing the battery cable. My car is a '71 vette and the batt cable is run under the driveshaft tunnel, lots of close tolerances under there. In my case, having only a 3 amp circuit connected when the car is unattended feels a bit more comfortable. Plastic burns easily! I'm subbed, would love to know which fuse/holder you settle on.

[slofut]

I don't have a fuse, but I do have a remote (keychain) selonoid mounted on the battery box so I can just hit the button and it kills all power coming from the battery (except the alarm). When I'm ready to go for a ride I just hit the key chain and all power is instantly back on. The only thing it kills the power to the radio so no channels stay programmed. I could easily fix that by wiring like I did my alarm, but really don't listen to the radio just the iPod that connects to the radio.

Do you have a pic of how you mounted the solenoid? Is your battery in front or back?

[ErikLS2]

I have seen that all over the net, but too many wires to try and route through my cab. I think the chance of my Quick Car cable chafing through it's shielding is not likely, but by chance a fuse would blow if it did. A fuse just seems like a similar effective method without all the additional wires.

A 300 amp fuse will blow on a direct short (assuming your battery is healthy enough to output that)but 290 amps can still do a lot of damage which is why a starter solenoid at the battery is the best option IMHO.

[badazz81z28]

Gotcha, I think the BUS site I was looking at suggested 200amps for my wire gauge.

[Vegas 69]

I run trunk mount battery with a Ford Solenoid to the large starter cable. Only hot while cranking. Then from the bat to power the car with #10 wire and fusible link.

[Kenova]

Ford solenoid in the trunk so starter cable is live only when cranking. I have a 4 gauge cable taking power up to the engine compartment with a 140 amp circuit breaker at each end and an 8 gauge wire from the alternator to the front circuit breaker.

Ken

[ErikLS2]

It's not hurting anything to have 2 circuit breakers but it doesn't help anything, just one right off the battery protects the whole circuit

[badazz81z28]

Just to ensure I'm comprehending here. What's really the difference between a 10 GA running live versus a 2 GA battery cable?

If the fusible link or fuse rather is closer to the engine, you still have wire from that point to the battery. So in a Chafing condition, you will still have raw battery power shorting to ground. Since AMPs will be high and the cable is small (#10), your chance of overheating and fire is higher right?

So in theory, my fuse at the battery is safer than a 10ga with a fusible link at the alternator?

[swicke69]

Did the mad electrical route few months back. Works great. First time doing electrical wiring on a car. Helps to read and talk to someone who knows what they're doing. So you can understand it well. Hiding everything and making things as clean as possible was the main challenge for me.

[ErikLS2]

Just to ensure I'm comprehending here. What's really the difference between a 10 GA running live versus a 2 GA battery cable?

If the fusible link or fuse rather is closer to the engine, you still have wire from that point to the battery. So in a Chafing condition, you will still have raw battery power shorting to ground. Since AMPs will be high and the cable is small (#10), your chance of overheating and fire is higher right?

So in theory, my fuse at the battery is safer than a 10ga with a fusible link at the alternator?

A 10 GA wire will burn up under much less amperage than a 2 GA wire will, is that what you mean?

The fusible link closer to the engine, with the battery in the trunk, leaves a large portion of wire unprotected and is not how it should be done. Just put an appropriate fuse right at the battery with the correct gauge wire for the length it's going to run and it will be fine. Every wire coming off the battery, except for the large one going to the starter motor, should be fused right at the battery, or as close to it as possible so that only a short wire exists between it and the battery. Now, you can have one larger gauge wire, fused right at the battery, running to your main fuse block mounted somewhere else in the car. To answer your question, yes, a fuse at the battery is the safest.

[1989GTA]

Dittos to the above post.

[badazz81z28]

I’d like to bring up this topic again. What’s changed in 10 years?


What I’m concerned about is a short to ground. I get proper routing and shielding is key, but that is not fool proof. I feel I need a breaker or a fuse.

[Vimes]

How much wire is where does not matter. Put the power interrupt at the power source. This means at the battery and at the alternator. No matter where a short is in the car, you want it to interrupt the source of power. Wire with no power running through it is just dead weight.

If chafing is a concern, use welding cable for the primary wiring inside plastic split tube conduit, with a retaining device every foot or so. The retainers will keep the wiring from moving much, the split tube conduit will wear through first so will be found during regular inspections. The welding cable is designed to be dragged around in a horrible environment for years, being walked on, sitting in various chemicals with sparks flying around landing on it. The environment under a car is way, way easier than a worksite so it'll last forever under there.

[DreKoushRanada]

Awesome thread! Does the same rules apply when using things like a Terminator X Max?

[badazz81z28]

What about these??


https://www.amazon.com/GENUINE-18980.../dp/B087BB4FDB