Voltage Issue

[Bluewater272]

I have a 2017 242 Limited S, and had a new and curious voltage issue that I've never seen before. We were out at anchor for a few hours listening to music, and all of a sudden I get the low voltage warning. I had glanced at the display a little earlier and was sitting at 12.1V or so, but maybe 20-30 minutes the alarm was sounding and it was reading 10.4V. I shut the batteries off as we were going to leave in a half an hour or so anyway. When I turned the batteries back on to depart, they were reporting 12.V again, obviously nothing had been done to charge them. Thought that was a bit weird. When we got to our second stop, we tied the boat up and listened to music again for another hour and a half, and once again I was at 12.something volts and it dropped to low 10s and alarm sounded. Shut off the batteries and went in for dinner - when I came out, they were back to 12.X.


Boat has the usual two-battery setup, maintained with a ProMariner charger. I finally got around to doing the DVSR modification so the batteries charge 'smartly', but this was done earlier in the summer and have had many trouble free outings since then. Confirmed that the DVSR is off when home charging, and only active while the boat is on the water (it's tied to the breaker that activates my amps and accessories). I haven't gotten around to doing the Fix for Connext Battery Voltage yet, but I suspect this is now on my to-do list.

Anyone have any ideas or troubleshooting tips? I'll be tossing a voltmeter in my bag for the next trip.

 

[Neutron]

I would have the batteries tested properly. One could be weak.
Its not abnormal to see a battery recover some voltage after sitting.

 

[swatski]

I didn't want to be the first to say that^^^ but that may likely be the case.
Once they reach that low... probably battery shopping time.

--

 

[Bluewater272]

Thanks for the input, I had seen batteries recover some voltage before, but going from 10 to 12 seemed like a lot. Guess I'll pull the house battery later and take it to have it tested.

 

[Bluewater272]

Had the batteries tested, both were fine. Did the connext voltage fix, @Mainah's instructions worked great, about a fifteen minute job end to end. No issues today but not an extended float period since weather came in quicker than expected.

Oh well, I'll probably upgrade batteries in the spring to AGM and up the house battery from Group 24 to 31.

 

[zipper]

There are battery state of charge charts on line. 12v is considered low, 12.7 is full charge on a resting battery. Measuring State-of-charge - Battery University or this one Batteries - Measuring State of Charge

 

[captainhook]

Had the batteries tested, both were fine. Did the connext voltage fix, @Mainah's instructions worked great, about a fifteen minute job end to end. No issues today but not an extended float period since weather came in quicker than expected.

Oh well, I'll probably upgrade batteries in the spring to AGM and up the house battery from Group 24 to 31.

Do it now, no reason to wait.