Over voltage.... or not?

French demon

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Hi buddies

I achieved the Madd Electrical modification (including a voltmeter instead of the ammeter) and my Demon runs very well

But...
My voltmeter reads 14 volts at idle and 15 volts while driving.
Is it normal or an over voltage?
Maybe my voltmeter isn't very accurate, I don't know.
Is a 15 volts charge dangerous for my battery? It's brand new.

François
 
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royslead

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For a long time 14.5- 14.7V was pretty much a standard at 1500+RPM. You're probably pretty close/ slightly higher than normal. Does it drop, with accessories on?
 

French demon

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For a long time 14.5- 14.7V was pretty much a standard at 1500+RPM. You're probably pretty close/ slightly higher than normal. Does it drop, with accessories on?

It seems to be a good news. I didn't try with accessories on.
I will test with headlights on tomorrow
Thanks
 

67Dart273

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For a long time 14.5- 14.7V was pretty much a standard at 1500+RPM. You're probably pretty close/ slightly higher than normal. Does it drop, with accessories on?
I don't know where you got that from........This is out of the 72 manual. Lead acid batteries share the same chemistry. They pretty much have not changed However, the OP's voltage is not that bad, really

voltage.jpg


OP the one big cause of over voltage is VOLTAGE DROP to the VR. The VR MUST see the exact battery voltage to charge/ regulate correctly. To check this, put the key in "run" with engine stopped. Connect on probe of your meter to the closest you can get to the VR IGN post (blue wire) Do NOT disconnect anything. The ballast resistor is likely closest. Stab the remaining meter probe into the top of the battery POS post. You should read a VERY low reading, the lower the better. Example: If your read .8V (8/10 of one volt) and if the VR is assumed to be "pretty close" at 14V then the battery will "run" at 14+.8 in other words whatever the system/ harness voltage drop is, that will add to the VR "set point."

ALSO check the VR GROUND. Start and run the engine at fast idle, and make the following check with all accessories off, and again with lights, heater, etc powered on. Stab one meter probe into the top of the battery NEG post. Stab the other into the mounting flange of the VR. Once again, the lower the better, zero volts is perfect

Also try "working" the VR connector in/ out several times to "scrub" the terminals and "feel" for tightness. Inspect the VR terminals and the connector mating terminals with a strong light and maybe magnifier for oxidation, corrosion, or damage

Remove the VR, scrape around the firewall mounting holes and the VR flange, and remount using start lock washers
 
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French demon

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False alarm. :)
I tested my battery with the engine running : 14.7 volts (engine shutted off : 13.6V).
In fact, it's my in-board voltmeter which is'nt very accurate. Instead of 14.7V, it reads 15+.
Poorly calibrated Chinese product :rolleyes:

And effectively, the voltage drops with headlights : 14.1 volts.
I think my regulator is doing his job properly

François
 
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