Voltage output too high?


wjhpc

wjhpc

GT Owner
Jan 5, 2014
7
Tucson, Arizona
I have noticed that the voltmeter is always a line or two to the charge (right) side of center. I threw my multimeter on the battery while at idle and got 14.2 - 14.4 volts. Is this within spec? Same reading on the voltmeter and on the multimeter with a fully charged new battery. I want to make sure i don't have a regulator issue that is overcharging the battery.

I posted this question previously in my post on my old exploding Optima. Xcentric is the only one who responded, and he feels that this is too high a voltage output and that 13.1 volts or so is correct for a warmed up car. The workshop manual is not too much help - it says spec range is 13-15 volts. I believe voltage regulator is internal in the alternator, and a bear to remove the alternator. Before I start messing with this, any other thoughts on whether this voltage output is high enough to justify action?

I don't want to burn out/explo0de another battery, but I don't relish the steps described in the manual to remove the alternator!

Thanks,

Jim
 
A quick internet search shows that 13.8V should be the maximum long term voltage for wet cell batteries in good condition, with 14.4V short term (8 hours max). Your 14.2-14.4 may be fine if it drops off after a short ride. It may also go down at higher rpm than idle.

Howard
 
Howard said:
A quick internet search shows that 13.8V should be the maximum long term voltage for wet cell batteries in good condition, with 14.4V short term (8 hours max). Your 14.2-14.4 may be fine if it drops off after a short ride. It may also go down at higher rpm than idle.

Howard
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Howard:

Unfortunately, it is 14.15 at idle after a long drive - never seen it at less than that. This is also born out by the dash voltmeter gauge which is always steady at 2 hashes right of center.
 
I'm in Florida or I'd check mine for you. If your charging voltage is too high it must be corrected or your new battery may go the way of the previous one. I wouldn't panic until you get some voltage measurements from some others on the Forum.

Howard
 
wjhpc said:
Howard:

Unfortunately, it is 14.15 at idle after a long drive - never seen it at less than that. This is also born out by the dash voltmeter gauge which is always steady at 2 hashes right of center.
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That's a little high but if you don't always for long drives it isn't that bad. I had a Honda that was over 15V and I never had a battery problem, but most of my driving was under 1 hour at a time.

Though IMO a lot of headlights failed prematurely.
 
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My radar detector shows voltage in the corner of the display.
Most of my cars run just over 14 at idle with out any other electronics on.
Once A/C, radio, lights, or any other electronics are turned on it drops to upper 13's.
I'm would think the various engine controls (ignition, injectors, etc.) would pull from that as well as demand increases.
The voltage while driving is probably closer to 13.5 give or take a little.

Jeff
 
Thanks guys. I think i will take it out for a drive, get it warmed up again, and then check the voltage with air on and fans turning. Rainy in Tucson today - will wait a day or so. Anyone else with a multimeter handy who could check voltage on their GT at the battery, with car running after a good warm-up drive? Good excuse to go for a spin!

Jim
 
BlackICE said:
I had a Honda...
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And you trash Volvos? BAHAHA! ;)

Your battery voltage should be 12.8. Did you check that? If it has a weak cell, the charging rate will be high.
 
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Xcentric said:
Your battery voltage should be 12.8. Did you check that? If it has a weak cell, the charging rate will be high.
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13.5V

Jim
 
You should check the battery's voltage with the engine off and after a short discharge of the battery, like turning key on for a 2 seconds and then off. Then take the reading. They always read high just after a charge without any current being drawn out before.
 
That's not right. I mean voltage with everything off.
 
BlackICE said:
You should check the battery's voltage with the engine off and after a short discharge of the battery, like turning key on for a 2 seconds and then off. Then take the reading. They always read high just after a charge without any current being drawn out before.
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Good point. The battery is 13.0V after dissipating the surface charge.

Jim
 
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