Voltmeter reading? Accuracy? Options

[SKL1]

Trying to figure out how accurate the OEM voltmeter is in my '73 2.0. To make a long story shorter the engine in the car is a much modified 1.9 from my '71, with approx 120K miles on the alternator.

Voltmeter reads around 11V and drops to 10 if I turn on the headlights. Immediately goes back to 11 or just over that with the lights turned off.

Replaced the voltage regulator this AM and did a test drive with no change. Gauge never gets close or above 12V. Makes me afraid to drive it at night with the lights on and go very far.

Do I need to go through the hassle of rebuilding the alternator or trying the alternator from the original 2.0 engine that has about 70K miles on it?

Better way to get a more accurate reading of actual voltage?? I hate electrical issues!!!!

TIA.

[mjrrti]

Trying to figure out how accurate the OEM voltmeter is in my '73 2.0. To make a long story shorter the engine in the car is a much modified 1.9 from my '71, with approx 120K miles on the alternator.

Voltmeter reads around 11V and drops to 10 if I turn on the headlights. Immediately goes back to 11 or just over that with the lights turned off.

Replaced the voltage regulator this AM and did a test drive with no change. Gauge never gets close or above 12V. Makes me afraid to drive it at night with the lights on and go very far.

Do I need to go through the hassle of rebuilding the alternator or trying the alternator from the original 2.0 engine that has about 70K miles on it?

Better way to get a more accurate reading of actual voltage?? I hate electrical issues!!!!

TIA.

I just bought a cig lighter usb charger on Amazon for about 9 bucks. It has a digital volt meter built into it. I bought it for usb use but it reads the same as the aftermarket sun pro voltmeter I have in my car. Should give you a good idea of where your factory gauge stands. I don’t know how to attach a link but here is a pic.

[mjrrti]

The brand didn’t show in my pic but it is zeehoo. There are a bunch to choose from anyway. (IMG:style_emoticons/default/smile.gif)

[930cabman]

I have found voltmeter readings somewhat erratic, but mine does read 14V often and has never let me down. But I also have one of the cigar lighter "meters"

[emerygt350]

It's really not the voltmeter, I checked mine against a nice multimeter and it shows pretty dead on to that. The problem is where it is tapped into the system. Unless you run a direct wire from the volt meter to the battery you really only have another method of knowing your brake light is working.

I put a relay inline using the original wiring of the volt meter to trigger it. I have fused wire running from the relay to the battery and to the relay -> volt meter. The volt meter is now key activated (using the original wiring) and it only tells me what the battery is seeing. I went from a situation you describe to a nice steady 13.8.

I also use a digital adjustable voltage regulator and highly recommend them. Cheap, sturdy, and fits the slot.

[GregAmy]

Trying to figure out how accurate the OEM voltmeter is in my '73 2.0.

It's not. Measure the voltage at the battery while the engine is running.

My voltmeter gave me enough scares - usually while well away from home - that I just removed the whole center console to give my 6'1" frame a bit more legroom. The idiot lights and fuel gauge-installed oil temp keep me honest.

I did add some extra LEDs to catch my attention, though. - GA

[SKL1]

Thanks. The meter in the lighter sounds great but I took the lighter out some 40 years ago and replaced it with an oil temp gauge.

I'll measure at the battery and see what gives...