Charging issues

Donald Tyson · Joined: 24 Jul 2023 Posts: 578 Photos: Thistle

Alain, both house batteries are 12.08V. The starboard starting battery is 6.1 and is hooked parallel to the port side which is 12.8....13.3-13.4 with the solar on and the Stbd battery turned off.

Donald Tyson · Joined: 24 Jul 2023 Posts: 578 Photos: Thistle

I'm a bigger sort of guy and I can't see any switches on the charger or the inverter. I've used my camera to peer in to the back sides. Nothing. In the Starboard battery box there are fuses to starting battery charger and also a breaker to the house batteries. There is also a switch to turn on the DC Inverter. The little screen on the Inverter reads 11.9. not enough.

Tomorrow I replace the starting batteries and will re evaluate.
I'll also be getting a new 50 amp adapter to connect my house power to the boat.

I'm about at the end of what I can tolerate. Time for a technician.

alainP · Posted: Sat Jul 12, 2025 11:35 am Post subject:

Don, if your inverter is connected to the house batteries (as it should be) and those batteries read 12.08 V the 11.9 V at the inverter makes sense, the slight voltage difference is the loss in the wiring connecting batteries and inverter.
I agree that hiring someone to sort things out is the right move. Make sure to get a diagram when everything is said and done,

Tom Hruby · Posted: Sat Jul 12, 2025 4:26 pm Post subject:

First of all: if your battery is fully charged and only reading 12.08 V you need to replace the batteries. A fully charged Lead Acid battery (AGM or Flooded) should be reading 12.6-12.8 V when fully charged, and with no load on it.
Also, if the voltage at your inverter (battery end) is reading less than the battery when it is not in use, the voltage drop is not a result of the wires, but rather a poor connection (most likely corrosion).