M1008 Alt overcharging at 15.1v

[LanceRobson]

My driver side alternator is putting out 15.1 volts. Is this repairable or adjustable?

Thanks

Lance

 

[Westech]

That is not really too high.. you sure the battery is not weak and trying to charge up? The norm is around 14-14.8 volts.

 

[LanceRobson]

The battery seems OK.

The charge indicator is at the upper edge of the green, It was the same with the previous set of batteries,

Lance

 

[nk14zp]

I would not worry about 15.1 volts my self.

 

[Dodgeman1941]

Our M1009 also runs with the voltmeter sits at the top of the green, about a 1/2 a neddle with off from red.

While we're talking about cucv alts {if you don't mind me kind of hijacking}, my ALT 1 light stays on when the truck is started untill you give it just a slight rev, then it goes {and stays} off and the voltmeter jumps up to the above mentioned location and all the 12v accys go to the normal operating level. Do you other guys have this happen?

 

[hobie237]

You are losing the voltage regulator. I'm not sure what's involved with replacing it, but when this happened to me, just driving home (20 minutes or so) was enough to fry one of the batteries pretty good and boil off some electrolyte. I just dropped the unit off for a rebuild, which is $100 or so.

As for the light being on until it's revved up a bit, that's pretty normal.

 

[doghead]

I went out and measured mine for a reference. Not running, I had 12.80v DS, and 12.88v PS. Running, I had 14.65 DS, and 14.78 PS My system is working well.

 

[crusty]

Before adjusting anything, I would check all your connections for corrosion. Also check the leads for voltage drop. This frequently indicates corrosion in the terminal ends. Check both the positive and negative leads.