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Current Draw from Average Vehicle Starter

Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=53398
Printed Date: May 12, 2024 at 1:12 PM


Topic: Current Draw from Average Vehicle Starter

Posted By: maxxam
Subject: Current Draw from Average Vehicle Starter
Date Posted: April 06, 2005 at 1:27 PM

Hi All,

This question relates to a problematic starter I have on my VW 4cyl engine.  When it gets warm out the solenoid cannot draw enough current through the stock wiring so the start will not spin up and the engine will not turn over.  You turn the ket forward and nothing happens, you hear a weak click sound that's it.  My mechanic, in an effort to save me money rigged up a wire that connects somewhere on  my starter/solenoid and the other end dangles close to my battery.  When it's warm out and the car wont start I have to pop the hood and touch the bare end of this wire to my + terminal on the battery and VROOM the car starts.  I was satisfied with this throughout the winter as this problem only appeared once a week or so.  It's now spring and as you can guess the weekly problem has now become a daily annoyance.  Just about everytime i go to start my car I have to pop the hood and blah blah blah.

I don't mind starting my car this way with the exception of having to get out and pop the hood everytime.  There must be a better way.  I was thinking... Could I install a puch button switch/relay combo to achieve this.

I have a spare automotive 30amp relay in my toolbox at home with standard pinouts I was thinking of using.  So my main question is....  Will a 30amp relay be sufficient to do this?

Your thoughts please and thank you,

Will



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Replies:

Posted By: Satkunas
Date Posted: April 06, 2005 at 4:13 PM
No, you'll need something that is able to pass at least 150A. I don't know of any relays that will handle this amount of current. You will need another solonoid.




Posted By: Satkunas
Date Posted: April 06, 2005 at 4:20 PM
One more thing...

I'm curious to know why the solonoid cannot pull enough current. Try running a fresh 4 gauge ground from somewhere on the motor straight to the battery. Most stock grounds are insufficient from the factory, and IIRC the vw used a braided strap that would corrode over time and may even be broken.

My hunch is the solonoid may be getting enough juice but the return ground path may be the problem. You can verify this by measuring a DC voltage from the motor chasis to the batter ground while cranking. If you read more than (+/-) .5vDC beef up the ground as mentioned.




Posted By: maxxam
Date Posted: April 06, 2005 at 4:29 PM
The return ground path may be the problem but if you notice above I mentioned that my mechanic installed a direct battery connection. So when it acts up all I do is pop the hood touch the 12 guage wire to the + post on the battery and the car will crank over.

This works well.

All i'm trying to do is complete that curcuit without getting my lazy ass out of the car to touch the wire to the + on the battery. I figured there must be an easier way to "touch" that wire to the positive without having to get out of the car and physically do it. A push button would do this in theory but to be on the safe side thought it would be best to incorporate a relay.

But what size relay? Keep in mind I only need to "touch" the + for one second.

About the 150amp current draw? I'm not to sure about that mainly cause i'm no expert. But I do know that most muscle car guys use a ford relay (80amp) on their big v8's becase they too have this problam with heat soak from header or exhaust manifolds to starter/solenoids.

hope that made sense.

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Posted By: Satkunas
Date Posted: April 06, 2005 at 4:35 PM
maxxam wrote:

The return ground path may be the problem but if you notice above I mentioned that my mechanic installed a direct battery connection. So when it acts up all I do is pop the hood touch the 12 guage wire to the + post on the battery and the car will crank over.



Just as I assumed before you are bypassing the solonoid entirely and the 12 gauge wire connected to the starter directly.

If all you had to do is turn the key to crank (like normal), would that be easy enough? I was hoping all your problems are from the ground in the first place, and by replacing it you could get rid of your 12 gauge jumper wire for good.





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