I have had my battery in the trunk for about 5 months using only an 80 amp fuse then all the sudden out of the blue the thing blows. I can't even see the metal inside cause the plastic got all melted. I just put in a 100 amp fuse and it started once but the center of the fuse is all discolored. I checked the whole length of the wire for shorts or bare wire but there was nothing. I put some extra electrical tape around the ring for the starter. What size fuse is reasonable? 200?

sorry if this is the wrong forum wasn't sure which one.


[Modified by Accord15, 4:07 PM 2/15/2003]

 

i would imagine you would want something 20-30 amps greater than what your alternator puts out...........so if the alternator puts out 80 amps you would want a fuse that is 100-120 amps.........

although i'm not 100% sure on this.......i would think that would be the best thing...........someone correct me if i'm wrong........

 

well i had the 80 amp in there and it is totally blown like the plastic is kinda melted but with the 100 amp the wire in the fuse is just all sorts of colors. It doesn't look broken but i am sure it is. It started once with the new fuse so who knows.

 

check your grounds on the wires running back there, they could be hitting the frame and blowing the fuse. not a good thing, but hey better to blow the fuse than the ecu

 

70-80amp should be fine. you have a short somewher

 

i am confused what you are saying are you saying the power wire could be hitting the frame? Because my ground is going right to the frame i under the trunk. I want to get outside and pull the whole wire out but we are buried in snow. I have two sperate wires running with fuses on both i have one for the fuse box and one for the starter only the starter fuse is blown so that means the problem is gonna be just on that wire right? I know its a stupid way to do it but i can't find a spliter or distribution block for a 2 gauge wire. Thanks for the help

 

This may sound like a crazy question, but as you give more data, now it appears the fuse that is blowing is the starter fuse? Correct?

Did things work right when the weather was warm? THen mess up with cold weather? Those starters pull several hundred amps (up to a kilo amp) for about 250 milliSeconds while they are spinning up. (Data from a buddy that made very light engine start batteries for racing aircraft.) Fusing the starter supply is going to be tricky. Share the answers and we will all try to help out.

Regards,
BigMoose

 

yes it is the starter fuse its funny i just talked to my uncle like 5 minutes ago and he was telling me the same thing he said in some of there trucks with auxilery(sp?) batteries they use 400 amp fuses on them. He is was a mechanic in the army so i trust what he says. Any that is exactly what it did the 80 amp fuse worked fine all through the fall when temps were warmer. So what do you think? About how many amps does an h22 starter pull when starting?

 

Very impressive. You actually put a fuse inbetween the Battery and the Starter??.. I would've used a Fusible Link.. But anyways..

If I remember correctly, the Starting Circuit in a vehicle is supposed to be the only circuit that is not fused. So there's my answer..

But if you want to fuse your Starting Circuit, it'll take a little more thinking on your part.. Sure the 80 amp fuse was sufficient for the warmer months.. You have to remember that Staters draw a lot of Amperage from the Battery.. And as the weather gets colder, the Starter will have to draw more Amperage to crank over the engine..

So if your Starter draws 75A and you're using an 80A fuse in the Fall, you should be fine.. Funny thing is, my GSR draws abou 110A.. Anyways, as the weather got colder, those 75A that the Starter needed eventually exceeded 80A and BANG!.. The fuse blew..

Here's a little tip...
At 80 degrees Farenheit, the Starter draws 100% of its needed Amperage.. At 32 degrees Farenheit, the Starter draws 150% of its needed Amperage.. And at 0 degrees Farenheit, the Starter draws 200% of its needed Amperage..

Does any of that make sense at all?

Here's what I would do if I were to add a fuse to my Starting Circuit.. I would first get a Starter Draw test to find out the approximate Amperage Draw the Starter needs.. And I would fuse it according to that number.. And as the weather gets colder, I would change the fuse to a much higher rating to prevent the smaller fuse from blowing..

But hey, I could be wrong.. I'm pretty sure there's a whole bunch of other dudes on this board with a better Electrical Know-How that could help you fix your problem. I'm just throwing in my 2 cents..

Good Luck, and BE CAREFUL..

 

OK, now we know what was going on. The cold weather made the starter turn slower and pull more current. Mystery solved! Remember that starter locked rotor current can be near a kilo amp.

Now for the solution, go to www.waytekwire.com and buy a 200 amp fuse number 46274 for about 4 bucks, buy a spare 250 amp fuse number 46276. Buy the fuse holder with cover number 46039 for about 6 bucks, and when the parts come in your in business..... Use good crimp terminals on your wires and if you don't have them waytek has them too along with the distribution blocks you wanted. Have fun with their web site. It's one of my best kept secrets...........

Regards,
BigMoose

 

i do not understand why you would not fuse cable going to the starter. I know it did not have it when the battery is in the front, but now the wire is going through the firewall so there is more change of the wire grounding on the metal there. So without a fuse isn't the car gonna catch on fire from all the sparking and **** (if it even rubs through) I thought most everyone put a fuse and a holder when putting the battery in the trunk. Well either way i gotta wait a few days to do anything my car is buried under 2 feet of snow. this is a dumb question but how do you test the draw on the starter? thanks for all the help

 

I have had three cars with the batteries moved to the rear. A '92 Protege, an '83 GTI and a '92 Jetta. All these vehicles were winter driven. I lived in Buffalo, NY all my life,so temps get damn cold. I used an 80 amp circuit breaker instead of a fuse. I have never had a problem with any setup.

Couple of questions;
1) Is the wire running through the fire wall grommeted? If not put one on or that wire could wear through causing some problems.
2) Where inline is your fuse placed? Close to the battery or closer to the starter.
3) When you did your wiring, did you replace the starter wire with better guage/quality wire?
4)Are the connections on the starer clean etc.? If not this could cause an excessive draw.
5) How long is your ground wire? The shorter the better, typically 6-10 inches.

These are just some questions to get your noodle working. I will try to help you from my experience. Also, the fact that the original fuse was melting is an indication that the wires are heating up too much. Make sure all your grounds are good. Clean all contact areas, etc.

BTW, sucks that there is so much snow. I'm buried in about 22 inches now in Baltimore, MD.

 

Aren't there fast acting and slow acting fuses. A slow acting fuse wouldn't blow even though there was a large initial spike that exceded the rating.

 

some one correct me if i am wrong but i couldn't i jsut run a 200 amp fuse. It only there to protect me if the wire rubs through and shorts out and in that case it will blow most any fuse right? I checked the whole wire and i do not see any shorts i cleaned all the grounds and the positive wires. I think i am going to add another ground to the battery just to be safe. I can actually get out of my driveway now so i am gonna go out and try the 200 amp fuse. I'll post results later tonight

 

All they had was a 300 amp? What do you all think should i try it? It would still blow if the wire rubbed through wouldn't it?

 

i dont want to hi-jack your thread or anything, but is it necessary to run a separate wire for the starter? if i understand you correctly, you have two wires running from the battery in the back to the engine bay, right? well it seems like you would technically only be using one at a time (the car is never running and starting at the same time, except for like a split second, right?) so would i need to run two wires? or would one work ok? why not just one big wire from the back battery to the existing battery cable in the engine bay?

thankyou

 

i wired it quit dumb actually but i have been to lazy to change it you can run just one wire and i believe wire it to the fuse box and have everything running out of there or run one wire and get a splitter or a distribution block (i can't find one for a two gauge wire) and then run one wire to the fuse box and run one straight to the starter. if anyone has a better way chime in. You could just connect the wire to the existing one but i did not want the mess of connecting the two i just wanted a solid wire. Probably would have been easier just extending it.


[Modified by Accord15, 9:23 PM 2/19/2003]

 

Ok now i have no idea what to do. I decided to just put the battery back up front until i can get a couple of cuircut breakers but it does the exact same damn thing. I got all new cables i even added an extra ground just cause and i charge the battery ( i actually tried 2 batteries that i know are good) and i still have the new starter in and all it does is click once. Does anyone have any ideas i am desperate i have absolutly no idea what else i can do or what else it could be.