High Voltage Question

[boater2018]

We took out our 2000 210 Sundeck this weekend for the first time and it ran great! I did notice that the voltage gauge read 16 volts and don't remember it reading that high before. Yesterday, I did some checking with the voltmeter and read 11 volts on the battery posts (not running), when I crank it and it is running, I get 13 volts on the battery terminals and the back of the gauge while the gauge reads 16 volts....also, when the boat is NOT running, it reads close to 14 volts. I assume the gauge is bad based on this and it needs to be replaced? I think my battery is also on it's last leg, but I want to be sure the voltage issue is solved before I replace it. FYI, it has the 5.0 EFI Mercruiser engine in it.

 

[Highliner]

If you read 13V at the gauge while it was reading 16V I think you've diagnosed the gauge as inaccurate (assuming you trust your meter). 14V at the gauge with engine off would seem to verify this result.

11V is very low for a battery at rest.

 

[electricaldoctor]

Remove battery cables and load test your batteries individually before going any further. Then check voltage outputs from your charger and alternator for proper voltage before connecting any wires back to your batteries. After you are satisfied with the DC voltage readings you can deal with your onboard DC volt meter and recalibrate or replace if required. If you have any bad batteries in your battery banks, replace them as a set with fresh batteries as your bank will only be as good as your weakest battery.