BDofMSP
Guru
- Joined
- Sep 5, 2013
- Messages
- 908
- Location
- USA
- Vessel Name
- Gopher Broke
- Vessel Make
- Silverton 410 Sport Bridge
Friends, I'm hoping for some thoughts on the behavior of my charging system.
I left the boat Sunday afternoon, plugged in to shore power and charger on, fully charged, showing 13.6 volts. When I boarded tonight at 9PM both monitors showed around 12.6 volts. Hmmm,
I flipped on the 12V breakers that I normally turn off when I leave (fresh water pump, head, lights) and the 120V circuit for the hot water heater. Immediately the battery monitors (Victron SmartBMV) popped back up to 13.4 volts.
The Victron allows me to look at the battery voltage and amperage history, so I did. What I found is that for whatever reason, yesterday (Wednesday) at 2PM voltage started to drop steadily from 13.6 until 4PM when it hit about12.8v. It then spiked temporarily to 14.5v for an hour, and then it dropped back to 12.8v. It then just tailed off over the next 26 hours until it hit 12.6v and I arrived. A screen shot is attached. Both battery banks show identical behavior. I have no idea if shore power was lost when the spike occurred, but I didn't do anything to turn it back on when I arrived, and it was working.
Interestingly, current never varies. It sits right at 0 amps, presumably because the charger us supplying power for the few 12v things that are still running (auto bilge pumps, LED on phone charger left plugged into USB port, etc.). Yet voltage tails off, not significantly, but slowly and surely.
For completeness, the charger is a ProMariner ProNautic 12-40. The batteries are FLA and are 1 year old.
Any thoughts on why voltage would drop off with no current draw?
Thanks,
BD
I left the boat Sunday afternoon, plugged in to shore power and charger on, fully charged, showing 13.6 volts. When I boarded tonight at 9PM both monitors showed around 12.6 volts. Hmmm,
I flipped on the 12V breakers that I normally turn off when I leave (fresh water pump, head, lights) and the 120V circuit for the hot water heater. Immediately the battery monitors (Victron SmartBMV) popped back up to 13.4 volts.
The Victron allows me to look at the battery voltage and amperage history, so I did. What I found is that for whatever reason, yesterday (Wednesday) at 2PM voltage started to drop steadily from 13.6 until 4PM when it hit about12.8v. It then spiked temporarily to 14.5v for an hour, and then it dropped back to 12.8v. It then just tailed off over the next 26 hours until it hit 12.6v and I arrived. A screen shot is attached. Both battery banks show identical behavior. I have no idea if shore power was lost when the spike occurred, but I didn't do anything to turn it back on when I arrived, and it was working.
Interestingly, current never varies. It sits right at 0 amps, presumably because the charger us supplying power for the few 12v things that are still running (auto bilge pumps, LED on phone charger left plugged into USB port, etc.). Yet voltage tails off, not significantly, but slowly and surely.
For completeness, the charger is a ProMariner ProNautic 12-40. The batteries are FLA and are 1 year old.
Any thoughts on why voltage would drop off with no current draw?
Thanks,
BD