Virtue of acr relays

[Cutwater28GG]

What is the value of the Acr relays?

I returned to the boat today to find all batteries low. The shore power cable had come out of the socket with the house batteries turned on to keep the fridge cool.

I was expecting that the house batteries to be dead but to find the engine and thruster battery low suggests that the acr closed and let the engine battery attempt to charge the house battery. To no avail and now all batteries are low.
Admittedly the engine and thruster seem to have more volts than the house as if the acr closed but still not enough amps to start the engine.

This seems like a terrible design.

I’d really also like a voltage sensitive switch to turn off the fridge if the volts drop too low. feeling annoyed as it’s ruined my day on the water. :cry:

 

[stwendl]

In general, I turn off all consumers with the main battery switch when the boat is unattended for a period of time. I also have remote boat monitoring by "boat command" which allows me to check in on such situations on top of being an intrusion monitoring system. The system would even allow you turn on things if needed remotely (if properly configured and installed)

ACRs on our boat are mostly useful when the engine is running to charge the separate circuits. The onboard charger charges each battery bank and the ACRs should not engage (at least that is my expectation based on the wiring)

Without copying stuff, here is the explanation by Blu Seas. https://www.bluesea.com/support/article ... _Explained

If your batteries all went down, then something is not connected or configured correctly

-sww

 

[BB marine]

If wired properly each circuit should be isolated. Make sure cross-over is off . If the isolation relays are working properly the relays will isolate the house from Cranking Battery and will isolate the thruster from the Cranking Battery.

 

[Cutwater28GG]

thanks all. but Im puzzled
my cross over was off.
engine and thruster batteries were off.
inverter was off and inverter breaker was off.
just house batt on.
they should be isolated.

could the voltage coming in from the solar during the day somehow be tricking the ACR's to open when in fact they should be shut...

my boat wiring is different to the newer boats as things like the fridge do not have a separate breaker. just straight into the house breaker switch.

 

[BB marine]

That is how our C26 is wired. If I don't want the fridge on I pull the fuse located in the panel in the head. I have left it on without 120V power while traveling (Towing) it has pulled the battery voltage down but never touched Cranking battery or thruster. I belief if the green light is on it is closed when the relay senses a voltage differential it should open and the green light should go off.