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funky voltage reading after welding ....

Posted: Wed Feb 25, 2009 7:51 pm
by MODIFIED
I thought I might have messed up my electrical , but on the contrary? :?:

Last night, I fab-ed some brackets out of hot rolled steel to effectively secure an Arctic top whilst in place upon the vehicle body. I have a neg. disconnect on the battery that I made sure was "off". I hooked up a 220 mig with the ground clamped to the clamp securing the bracket in-place to that of the body and the Aluminum channels that frames the top.
After welding was complete and packed up for the night. I decided to run her around the block for some suds.

Normally, I'd been having trouble cold starting her up. she'd wind quite a few times before catching.

To my surprise, she cranked in less then two revolutions!!
I ran her to get her to temp, and drove off.
I noticed the Volt Meter was in the yellow zone when I revved in excess of 1500 rpm in gear and in Nuetral> bordering Green zone for good charge. not good.

I got worried I might have messed up the voltage regulator .

This morning, I started her up . Almost immediately the she cranked right up!!

yet the Volt meter was way within Green for charge? odd
she had choke and throttled up for cold start of course.

Funny, she seems to charge much better and start up like a champ? not complaining but, am I missing something?

I could not find any comparable info regarding welding on vehicle.

:? :roll: :roll:

Posted: Wed Feb 25, 2009 10:19 pm
by wesk
I doubt the ewelding had any effect.

I'll put my money on the ground connection which apparently improved after the short disconnect and re-connect.

Posted: Wed Feb 25, 2009 11:44 pm
by Bob_C
Hi,

Current takes the path of least resistance. It does not flow randomly throughout an object to a ground.

This being said, the only way I would suspect any serious damage could occur is if your grounding cable had a terrible ground (by paint, other non-conductive contaminants), or wasn't placed very close to the weld location (thus causing the current to travel to try to find the ground). Of course, this ignores the fact that you had a switch on the negative terminal of the battery to the frame. If you broke that circuit there, no current should flow.

Posted: Thu Feb 26, 2009 8:33 pm
by MODIFIED
GREETINGS AND THANK YOU BOTH FOR YOUR INSIGHT,
I concur that the upon welding, to obtain good ground with the least path of resistance upon what one would be welding. Though, am intrigued by the fact the vehicle starts and charges better. :?: