question

jayeshleman avatar image
jayeshleman asked

Can I use the Smart Battery Protect to disconnect a single circuit (ie refrigerator) if the battery drops below a certain voltage?

Looking to see if this device needs to be connected to the battery or can be installed inline with my marine refrigeration.


I'm on solar and want to make sure if I leave fridge running and we get a number of cloudy days that the fridge is turn off if voltage falls below 12 V.

Battery Protect
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3 Answers
Mark avatar image
Mark answered ·

Yes that should work fine, just remember that during compressor start up there will be a large current surge (~10x normal operating current), so make sure that you choose a battery protect device with sufficient capability to accommodate this.

They are capable of a fairly generous 'peak current' that they can sustain for ~30sec, so this rating can be used as a guide.

https://www.victronenergy.com/upload/documents/Datasheet-Battery-Protect-65-A--100-A--220-A-EN.pdf

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jayeshleman avatar image jayeshleman commented ·

Thank you Mark for the confimation. My fridge with 10amp start up will be well under the Peak 250AMp.


I really appreciate your feedback! I will give it a go and let you know!


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Tom avatar image
Tom answered ·

The Victron BPs have preset voltage limits so besure to check if they meet your voltage needs. The standard BPs seem to be designed around lead Acid battery voltages. The newer Smart BPs can be customer programed with an app and wifi.

Basically the BP is a switch relay. You can also use a $10 Chinese PCB XH-M609 to to shut down your Fridge for low voltage shut down with or without the BP65. It is all in what you want to spend and your knowledge of electronics.

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jayeshleman avatar image
jayeshleman answered ·

I was able to install BP in-line with the Refrigeration compressor. I will however mention that the Voltage Reading just before the fridge compressor is lower than the voltage reading at the Shunt by about .5 volts. As such, when I had set the voltage to shut down at 12.0 volts, it was actually shutting down at 12.5 at the battery. Accordingly, I change the setting to shut down at 11.5 volts, at the Fridge, which now equates to 12.0 at the battery. Since my solar is pretty much keeping up with demand, I am not seeing the BP shutting off as much as I was initially. Overal, this is a great solution for letting a fridge remain in the ON POSITION while not having to worry about over drawing the battery in instances where there my be longer term limited sun scenarios.

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Mark avatar image Mark ♦♦ commented ·

Great to hear that you have it all up and running well.

But 0.5v voltage delta seems excessive to me, so I would highly recommend to upgrade your wiring thickness and check all terminals/connection's.

Another point/option if you have a BMV is to wire the BMV relay into the battery protect and use the BMV to trigger the low voltage or low SOC% shut down.

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