Starboard volt meter about 1 volt less than port

G

griff4

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Joined
Dec 31, 2013
RO Number
33534
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34
Our boat now 10 years old since new. Previously, both volt gauges read about the same. Now the port reads 14 volts at idle and 13 volts at 3500 rpm cruise. Starboard gauge reads about 1 volt less at idle and cruise. Any suggestions would be appreciated. Alternator new, batteries tight. Trying to find cause of lower reading. Thanks.
 
Could it be 10 year old gauges may very. Can you switch wires to test.
 
Measure the voltage at the batteries. Measure specific gravity.

How old are the batteries? All those symptoms can be caused by weak batteries.
 
Thanks, guys. Motors are Merc 350's with Gimler belts. Will be testing batteries and connections at various points. Will also swap volt meters. Griff
 
Could be the gauge or wiring. Check voltage at the battery and at the voltmeter terminal

Could also be the battery being tired and requiring more charging. Or higher load on one side

Not sure why voltage is lower at 3500 than at idle though
 
Yes, I would check the voltage across the meter terminals. This issue could be caused by anything from a corroding connection in a high current cable to a loose one somewhere along the line.
 
One battery is probably only used to start one motor only and is fully charged and doesn't need a big charge going into it hense the smaller charge, while the other battery is suppling voltage to things running on boat plus motor so more charge needed
 
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