Battery shows 80V when Merc 1500 is running

[Zac Penn]

The battery shows 12.6V before it starts, then when it is running it reads 80V's.

Any ideas?

 

[Zac Penn]

Nevermind. I had my multi-meter on the 200V dc selection which obviously makes a big difference if the motor is running. If you switch the multi-meter to 20V dc then it reads 12.6v off and 14.5v motor running. I wonder whyt he multi-meter reads so high when the motor is running on the 200v selection?

Either way is 14.5v at idle too much juice?

 

[Chris1956]

That system is unregulated, but bounded by the absorption of the battery. If you read AC voltage, the rectifier may be bad. If only DC voltage, it may be OK.

 

[emckelvy]

Sounds like your meter has a problem. It shouldn't change that drastically in value when switched upscale.

Fortunately, digital VOM's are really inexpensive nowadays, and an under-$20-on-sale-at-Sears meter should give you years of good service.........ed