over charging

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jimjimjimmy

jimjimjimmy

lobsterman
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I'm working in a 90 w 250 for a friend it was over charging to about 18 volts or a little more , by cleaning connections i got it down to 14.8 to 15 v it's about a volt higher than i would like would an adjustable regulator be able to get it down around 13.6 or so . or is 14.9 - 15 volts alright . Thanks .
 
About normal. 13.6 isn’t going to happen.

try a know good battery and see if it changes.
 
413 said:
About normal. 13.6 isn’t going to happen.

try a know good battery and see if it changes.
Click to expand...


it's a new battery we put in today . i just don't want him to cook the wiring over time because it will be me fixing it .
 
I agree, I like to see just under 14v for charging voltage. I tried 3 different regulators and 2 different batteries and I know have it charging at 14.2 volts. It was sitting close to 15 an AC delco regulator and one regulator had it at 15.4 volts on a fully charged battery which is to high in my mind. I also had no loads on either and both batteries were fully charged both batteries tested good. The regulator I settled with was a Rock Auto cheapy unit, not sure how long it will last.
 
Couple things.......first, many regulators are temperature sensitive or temperature compensated. So warm up the engine fully, get the battery "clear up" and "normalized" even if you have to charge it.

Battery may be old and starting to sulfate, therefore try another known good battery, or hook that one into another vehicle after checking the charge voltage of the one in there

Next make sure voltage drop is not a problem. Check voltage drop between the VR sense wire and the battery + with key "on" and engine "off." Check it again running

Check ground. with engine running "fast" check V between VR mounting flange or ground post, if separate, and battery NEG. Check again with all accessories, lights, heater, etc running

For both these tests you are hoping for a very very low reading, the lower the better. Over say, .3V or more means you have a "drop" problem.
 
Keith Mopar said:
I agree, I like to see just under 14v for charging voltage. I tried 3 different regulators and 2 different batteries and I know have it charging at 14.2 volts. It was sitting close to 15 an AC delco regulator and one regulator had it at 15.4 volts on a fully charged battery which is to high in my mind. I also had no loads on either and both batteries were fully charged both batteries tested good. The regulator I settled with was a Rock Auto cheapy unit, not sure how long it will last.
Click to expand...


Keith have you ever tried an adjustable regulator ? I'm just wondering how they work and when to use one .
 
I bet there is no issues with dim head lights!
Typically it’s a ground that is dirty or non existent or faulty regulator. Or bad ground on regulator or even previous repair that is wrong.
 
jimjimjimmy said:
Keith have you ever tried an adjustable regulator ? I'm just wondering how they work and when to use one .
Click to expand...
No I haven’t tried one but if I would of known there was adjustable ones I would of tried one. It was very frustrating just trying to stop the over charging voltage even though I thought I had coveted all the bases. And yea my voltage on the regulator was only .1 of a volt different than battery voltage.
 
13.8-14.7 is pretty normal, 15V is not especially worrying. My 2012 Cruze occasionally charges at 15.4V if the battery accepts charge, when its cold out.

I would ask if you are measuring at the back of the alternator or at the battery? I think you should give us readings from both.

Typically the sense wire is trying to maintain a voltage at that location which can be largely effected by the condition of wiring or connections. That and the OE regulator has to have a good ground.
 
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