Battery gauge reading only 12v while underway

Chrisvr6

Is that right? Always thought it should be 13v.

MarkB

At should be close to 14 V if alternator is working.

JC290

What all did you have on?

212rowboat

2.11 per cell x 6 cells = 12.7 (nominal) volts on a happy 12vdc battery... it needs at least 13v to maintain a charge, and 13.5~14.3 to charge... if it's below 12.6, you've got a bad cell and a dying battery.  alternator should produce 14ish vdc.... some computer controlled alt's can slip into 'maintain' mode and hold steady 13.5vdc, or burst to 14.5vdc if needed.... you don't want to hit a 12vdc battery with more than 15vdc unless it's designed for it. 

before you get worried, though, ask yourself "if analog, how far from the battery is the gauge?"

Chrisvr6

New alternator. No accessories on. Doesn't matter if selector is on pos 1,2 or both. I should put a multimeter to the batteries to see what they read when its running i guess. 

youstolemybeer

When Rinker wired the boat they ran one Big power wire to the dash board. From this wire they ran all the dash guages and accessories. The voltage you are getting at the dash is NOT the true battery voltage. For that you need to hook up a digital VOM . Only then will you get an accurate volt reading

alexwong

I have the same problem. My 2008 Rinker 280 battery gauge on the dash board also reading 12V while underway. I will put a multimeter on the battery terminals and check the voltage. 

Dream_Inn

Al, I do have an isolator, but both engine batteries read 13 on the dash when running.   My house on electrical panel does as well while running.

MarkB

Mine also shows 14V while underway.

Dream_Inn

Al, I do what?  I know I have an isolator.  but still read 13v.