12 Volt Battery Reading Over 14?

[Pete7]

When was the 9v battery in the digital battery meter last replaced. They give odd reading when the battery runs down.

Pete

[kmacdonald]

Buy a Fluke digital multimeter.

[DragonflyBob]

Originally Posted by kmacdonald

Buy a Fluke digital multimeter.

I agree, don’t go cheap on a multimeter. It’s a good investment to buy the best.

[Ratty1978]

More of an observation than a solution. In the old days, it was normal to calibrate meters. Maybe there's a way to reset your digital meter?

[wholybee]

Originally Posted by DragonflyBob

I agree, don’t go cheap on a multimeter. It’s a good investment to buy the best.

You need a good meter, but it doesn't need to be a Fluke. Not everything Fluke makes is good, and other brands make good stuff too.

[Shaneesprit]

Originally Posted by Wotan

Well I went out and did some tests. The digital one is mine, the analog one is the second opinion. I'm not sure if I'm reading the analog one correctly, so I'l just upload the photos. They got warped when I tried to upload them.






Like I said, no way they could be charging. The boat is anchored in the lake with no solar panels and the engine off.


Any ideas?

I wouldn’t trust with of those meters - Go buy a Fluke

[geoff3nebel]

Put a new, fully charged, battery in your meter and see if the reading changes. When meter batteries run down the readings can be erratic

[danno7]

Originally Posted by Statistical

The analog meter looks like it is reading around 12.5 but hard to tell for sure. You have it on DC25 setting so you use the 50V line and halve it. It looks like around 25V so half is 12.5V. Alternatively you could set it to DC50 and just read that line straight.

That is not the way to read an old Analog meter. If you have the selector on the 25 volt position, that means it reads 25 volts at the maximum. You are supposed use the 250 volt scale and divide by 10.

In this case, ironically enough, it turns out it is the same voltage! About 12.5.

[wholybee]

Originally Posted by danno7

That is not the way to read an old Analog meter. If you have the selector on the 25 volt position, that means it reads 25 volts at the maximum. You are supposed use the 250 volt scale and divide by 10.

In this case, ironically enough, it turns out it is the same voltage! About 12.5.

It is not ironic, it is math. Using the 250 scale and dividing by 10 (what I would choose) or using the 50 scale and dividing by 2 will ALWAYS give the same result.

You could also use the 10 scale and multiply by 2.5, which would not be intuitive at all, but would still result in the correct reading.

[danno7]

Originally Posted by wholybee

It is not ironic, it is math. Using the 250 scale and dividing by 10 (what I would choose) or using the 50 scale and dividing by 2 will ALWAYS give the same result.

You could also use the 10 scale and multiply by 2.5, which would not be intuitive at all, but would still result in the correct reading.

Yes, i guess you are right. I never thought of that.

[Baronkrak]

Originally Posted by wholybee

... Using the 250 scale and dividing by 10 (what I would choose) or using the 50 scale and dividing by 2 will ALWAYS give the same result.

You could also use the 10 scale and multiply by 2.5, which would not be intuitive at all, but would still result in the correct reading.

At 25 the full scale is 25 at 50 the full scale is 50. 25 is more accurate than 50.

Using a 10 scale for measuring 12 volts really?

[dlj]

Originally Posted by Baronkrak

What about using the 250 scale?

Analog meters are more accurate when using a scale where the indication is closer to midway on the scale.

dj