Battery Switch Mystery

[Rick D]

When we were on a recent cruise, I noticed my solar wasn't charging the house batteries. I checked my Victron regulator. It seemed OK. However, when I pulled the sense wire that went to the battery switch, it showed 13.1 volts when the batteries were 12.4. Hum. I turned the battery (4-way) to off. It was then I noticed that the fresh water pump was still merry pumping as my wife washed dishes. Hmmm! So, I rewired the Victron sense directly to the batteries which solved the solar charging issue. Recently, I returned to the boat and replaced the battery switch which turned out to be a $60 cash investment and 4 1/2 hours of sweating and bruising inside a locker fighting with too-short battery leads. When all was done... no change. Grrrr. I had tested the main leads to the #1, #2 and Com and the only oddball was 10 volts read from the Freedom charger/inverter, despite the 120 volts disconnected as well as the main ground. I wrote it off as some kind of capacitor thing.
So, now I'm wondering what's going on? My first thought is somehow my solar feed is going direct to the Com port. It's been so long I don't remember. A dock mate said it could be the echo charge on the inverter, but I don't believe it was hooked up. Finally, perhaps the battery isolator has failed and I'm picking up the start battery current.
Snide comments, wild speculation, and helpful hints welcome....

 

[Davidasailor26]

What kind of battery isolator do you have? If it’s something like an ACR it will keep the batteries connected by design as long as either side is charging. My guess, which is pretty wild speculation without seeing a wiring diagram, is that the solar is connected to the 1-2-B switch output, and the isolator also is. In that case the solar would try to charge the engine battery, and the engine battery could provide power to the water pump even when the 1-2-B is off. But seeing a wiring diagram would go a long way to making a better guess.

 

[Rick D]

What kind of battery isolator do you have? If it’s something like an ACR it will keep the batteries connected by design as long as either side is charging. My guess, which is pretty wild speculation without seeing a wiring diagram, is that the solar is connected to the 1-2-B switch output, and the isolator also is. In that case the solar would try to charge the engine battery, and the engine battery could provide power to the water pump even when the 1-2-B is off. But seeing a wiring diagram would go a long way to making a better guess.

I don't remember, but it isn't an ACR. I replaced it about ten years ago. I don't recall how I wired the solar and will have to do an examination to determine that. A wiring diagram would have helped!

 

[dlochner]

Which model Victron Solar controller do you have? My Victron controllers do not have a sense wire, just a DC+ and a DC-. The current crop of Victron solar controllers must be connected to the battery before the solar panels are connected.

In order to troubleshoot the issue it is necessary to have a good wiring schematic, especially after the factory wiring has been modified.

 

[Rick D]

Which model Victron Solar controller do you have? My Victron controllers do not have a sense wire, just a DC+ and a DC-. The current crop of Victron solar controllers must be connected to the battery before the solar panels are connected.

In order to troubleshoot the issue it is necessary to have a good wiring schematic, especially after the factory wiring has been modified.

Yes, like I said to the first Dave, I sure wish I had made a diagram! Good lesson to those starting out. You tend to forget when you have had a boat for 25 years! In any event, when I said "sense" I was actually referring to the battery leads on the Victron. It's just solar in and battery out and the battery out also provides the sense. MPPT 20 amp.

 

[JamesG161]

Hunter wired the boat's OEM Solar Collector to the Start Battery, to Trickle charge it.

Depending on your new Solar Collector Amp output, you need an Isolator to prevent Over Charge.
________

the only oddball was 10 volts read from the Freedom charger/inverter,

Depending on the Model of Freedom ICG, you might need a House Battery Temperature sensor.

But your Solar Collector, with a Controller, should regulate that Start Battery.

Jim...

PS: I can help on this issue. Send me a PM if you need my help.