[TonyO]

As part of making an over discharge protection circuit I decided to check the calibration of the el cheapo flea bay voltmeter I installed. Damm thing can be as much as 0.8 Volts off!!!!

 

[kc2dgq]

I think that most of those digital voltage displays are not as accurate as one would like them to be.

The number displayed is not a critical as you think.......let me explain.
Knowing what your charging system is doing is more important than the actual numbers. at idle, you would not expect much charging taking place, but at the higher RPM, you want to see a higher voltage(system is charging).
Sitting at a stoplight with brake lights on and possibly the radiator fan running...you expect to see a lower voltage...this is normal.

I installed a simple LED on my dash that tells me what the system is doing...not the actual voltage....that keeps it simple, green is acceptable voltage, flashing green is charging, and red means battery voltage is low.

HERE is the link to my thread for my LED indicator install.

 

[Knifemaker]

Yes. Good voltmeters will usually say how accurate they are. (+/- 0.1 volts e.g.) Good ones also usually have an adjustment to alter them if they are wrong.

But yes, numbers are relative, if you check one against another that you trust, you will then know what to add or subtract when looking at the one that's wrong.

 

[Spockster]

When I looked at those, they had +/-1v in the specs, some weren't waterproof. Still better than not having one.

There's really a wide selection of meters now, just looking on Ebay.

 

[HardRock]

When I looked at those, they had +/-1v in the specs, some weren't waterproof. Still better than not having one.

There's really a wide selection of meters now, just looking on Ebay.

X2

I replaced my gas gauge with a voltmeter, now that part of my dash gives me info I can use rather then telling me that I still have a full tank with 75 miles on the trip meter.

 

[Spockster]

X2

I replaced my gas gauge with a voltmeter, now that part of my dash gives me info I can use rather then telling me that I still have a full tank with 75 miles on the trip meter.

Look at the miles on that puppy!

Meter looks factory that way.