Main Power Fuse

Tunes67 · Post by **Tunes67** » June 28th, 2007, 8:16 pm

I have relocated my battery to the rear of my car.. running a drycell battery (see my worklog for more info). I want to put a fuse on the main battery cable in the engine bay to protect the wiring in the engine bay if the long battery cable from the battery ever shorts out. But.. I have no idea what rating the fuse should be. I know it will need to be able to handle the current draw of the starter. But I dont know what that would be off hand. Anyone have this info or a link to point me to a product that is capable of doing what I am describing? Thanks in advance

Tunes67

mr1in6billion · Post by **mr1in6billion** » June 28th, 2007, 8:26 pm

Off memory the main fuse in the RS is 80amps and the GS is 100.

Tunes67 · Post by **Tunes67** » June 28th, 2007, 8:55 pm

Yeah but I dont think the starter draws through them stock.. in my car after these mods.. it will. I dont really need the fuse to be honest.. its just my paranoia that tells me to be better safe than sorry

Tunes67

shameem · Post by **shameem** » June 29th, 2007, 12:25 am

Some rough calculations with data from the manual page TD-15
RS-> 0.8kw -> 67amps
GS-> 1.7kw(max) -> 142 amps

PATDIESEL · Post by **PATDIESEL** » June 29th, 2007, 2:33 am

You would also want to get a fuse block with 1 input and two outputs as the starter at 145 amps will need to be a different fuse than what you use for the rest of the car (which would be the same as the main fuse in the engine bay fuse box). However, the only dual output splitters that I've seen use a glass tube fuse, you need one that will accept the large blade type which I've only seen in a cylinder type holder that uses one in and one out. Check radio shops as they are the most likely to have something pretty and functional for this purpose. I would think the easiest route will be to find a glass tube fuse rated at 140-150 amps since the tube fuse holders seem to be more common.
You might also do well to PM "chew" and see if he knows how to get what you are looking for. He seems pretty into the car audio scene.

chew* · Post by chew* » June 29th, 2007, 4:38 am

Pat the glass style fuses are highly unreliable and the max available is 80 amps. The ANL blade style fuses are very reliable ranging from 50-300 amps in 50 amp increments. He will likely need to use a simple splitter off the main wire and fuse the 2 wires seperately. Very smart to fuse from front to rear, the sole purpose is if the car was ever in an impact and the wire pinched a fire would occur. Of course there are other possible bad things that can happen.

Tunes67 · Post by **Tunes67** » June 30th, 2007, 1:00 pm

Thanks guys

Lots of good info. I will be out and about today and will see what I can find for fuses.. I was less than impressed with the current selection on ebay unfortunately. I'll post up in my worklog & in this thread on what solution I found for the issue.

Tunes67

PATDIESEL · Post by **PATDIESEL** » July 1st, 2007, 11:07 pm

Chew is psychic or something. I say, ask Chew, and he responds without being asked...

What makes the glass fuses less reliable? I would think it is all pretty much the same since they use a thin wire to restrict amps. I believe you are correct, but just not sure what the diff is. When I did my radio install they sold me the blade type since I run a decent amount of power and needed a 100 amp fuse, but never thought about what the differences are.

lakersfan1 · Post by **lakersfan1** » July 2nd, 2007, 7:21 pm

Personally, I'd run a circuit breaker for the main fuse. That would suck to blow a main fuse for some reason and be stranded because you don't have a replacement. I'd probably do a 200 amp to the front to cover all duties.

Tunes67 · Post by **Tunes67** » July 2nd, 2007, 8:07 pm

Lakersfan.. you read my mind.. thats what I was going to do originally.. but when I started reading up on the circuit breakers.. I found that they tend to be slow to trip and dont handle heat very well. And since its going to be in my engine bay.. that could be a problem. I also found that the more times they trip.. the easier they become to trip and the harder it becomes to get them to reset properly. At least the ones I found off of ebay (which are the ones I then researched). The fuses got a better review in all aspects. So that will be the route I am going to do. I have the main power wired up right now with no fuse in place yet. Once I do get the fuse holder and 5 or 6 spare fuses.. I'll stash the spares in various places around the car so I will always have one in case of an emergency.

Tunes67

chew* · Post by chew* » July 4th, 2007, 8:56 pm

PATDIESEL wrote:Chew is psychic or something. I say, ask Chew, and he responds without being asked...

What makes the glass fuses less reliable? I would think it is all pretty much the same since they use a thin wire to restrict amps. I believe you are correct, but just not sure what the diff is. When I did my radio install they sold me the blade type since I run a decent amount of power and needed a 100 amp fuse, but never thought about what the differences are.

The glass style are soldered in versus anl being a cutout on a solid piece of whatever they use.

Needless to say I have had even the 80 amps unsolder due to heat in the engine compartment and or possibly a bad connection before the darn fuse blew. Took me a few times to figure out that style was junk. I was like i don't get it its still solid but my test light says power is going in and not out. No problems since i switched to anl blade styles.

I think the glass fuses lose connection in the housing over a period of time which is they're flaw. Heat may warp the housing. The other style is bolted which is a far better connection than usingthreaded plastic to hold it in.