Very high resting battery voltage

[waterinthefuel]

I've never heard of this. I went to charge my deep cycle battery on my boat and it showed 14.2 volts and it's been months since it was used. It was not hooked up to anything. What could cause this? When I used it in March for spring fishing it had normal capacity and worked fine. It's about 9 years old now.

 

[GA_Boater]

What was showing 14.2 volts? Did you try another meter?

 

[KD4UPL]

A bad voltmeter. That's about the only thing that could cause a battery that's been at rest for moths to read that high.

 

[waterinthefuel]

It was the battery meter on the charger itself. It's worked normally before and never given an incorrect reading. At least not been more than a tenth or two of a volt off of what any DC voltmeter said it was.

 

[harringtondav]

Per GA I'd put a voltmeter on that battery, and check the voltage while you're applying a load. A reasonably good battery may drop to 10V or so when cranking. But if you've got a nine year old battery that still works, you're lucky -- and on limited time in my mind. Batteries are like people. They get goofy when they get old.

 

[Scott Danforth]

Verify the $2 meter on the charger with a good volt/ohm meter such as a fluke....and not a centech that you get for free from harbor freight

 

[waterinthefuel]

Oh yes. I'll be checking it before using it again.

I will say those cheap meters are accurate. I used one in A&P school for the electrical portion. One guy had 300 dollar Fluke I had a free one from HF. My answers on the electrical tests were the same as his. We checked voltage on a battery and his showed 24.13v DC. My free one showed 24.1. It only went back one decimal place. Good enough for me. (planes are 24v systems, not 12).

Where it did differ was checking OHM resistance. It would tell you about how much resistance but if you need to the 100th of an OHM, get a better meter. It was more like "I have continuity on this circuit or I don't." I wouldn't put much faith in the actual reading of OHM resistance on the meter itself.

 

[mike_i]

I agree with the other suggestions, get another voltmeter. I've used the cheap HF toy voltmeters, they're good for basic voltage measurements, I have one connected to my PV solar system I built. Let us know what you find.