Battery monitor

[Samarai]

Hi, pbo March 22, Project Boat article addresses the fitting of Victron BMV-712 battery monitor.
I have 3 battery banks. Domestic, Navigational and Engine.
How many monitors (at c.GBP 500.00 each) would I need to buy in order to monitor all three banks?
Cheers!

 

[Kelpie]

Whoever is charging you £500 for a BMV is ripping you off!! They should be more like £180.
Or you can buy a knock off version (Aili?) for about £50 on eBay or Amazon.
I personally wouldn't bother with a monitor on the engine bank either, it's doing exactly the same job as your car's battery and I bet you don't have a monitor for that.

 

[Samarai]

Yes, I forgot to mention I'm currently lying in Portugal so that's where the cost comes in... I'm renewing my batteries this spring and was looking at AGM for the domestic bank (3 X 100ah). Can I charge AGM batteries from my alternator and will they sit happily alongside my Nav (sealed but not gel, truck battery)?

Thanks for your help.

 

[VicS]

Hi, pbo March 22, Project Boat article addresses the fitting of Victron BMV-712 battery monitor.
I have 3 battery banks. Domestic, Navigational and Engine.
How many monitors (at c.GBP 500.00 each) would I need to buy in order to monitor all three banks?
Cheers!

A BMV-712 will fully monitor one battery bank and the voltage only of a second. Usually the domestic bank is monitored fully and just the voltage of the engine start battery.

It would be overkill to fully monitor the engine start battery or the navigation battery. Perhaps the voltage of one of these could be monitored by the BMV and a separate voltmeter installed to monitor the other.

Worth reading the documentation at BMV-712 Smart - Victron Energy

 

[Kelpie]

Yes, I forgot to mention I'm currently lying in Portugal so that's where the cost comes in... I'm renewing my batteries this spring and was looking at AGM for the domestic bank (3 X 100ah). Can I charge AGM batteries from my alternator and will they sit happily alongside my Nav (sealed but not gel, truck battery)?

Thanks for your help.

Ah good old Sopromar. Why not try SVB instead?
BMV-712 Smart Battery Monitor only 222,95 € | SVB

 

[Samarai]

Great thanks!

 

[KompetentKrew]

Consider the Victron SmartShunt instead - it's cheaper than BMV-712 and you view the battery status on your phone's screen using the app.

Like the 712 it will show the voltage and percentage state of charge of one battery, and just the voltage of a second.

You can change the SmartShunt's name so it shows in the app as, for example, "Boat name - domestic" or "boat name - navigational".

The SmartShunt also integrates with Victron's GX system if you want a fixed display and it is much fancier and more sophisticated than the 712, although I think this together is a lot more cash (looks like you need the Cerbo GX in order to run the display?). I believe you can alternatively run the GX software on a Pi.

How big is your navigational battery bank to be? I presently run the chartplotter and instruments off my domestic bank, which is 330Ah. I plan to increase the size of the domestic next time (maybe to 400Ah?) but I can't see myself separating them. I think the autopilot's motor uses a bit, but the instruments use little compared to the fridge. Having them both on the same bank means you can turn off the fridge on passage and preserve power for the instruments.

 

[Samarai]

Thanks. I'll definitely look at the Smart Shunt option.

 

[PaulRainbow]

A BMV-712 will fully monitor one battery bank and the voltage only of a second. Usually the domestic bank is monitored fully and just the voltage of the engine start battery.

It would be overkill to fully monitor the engine start battery or the navigation battery. Perhaps the voltage of one of these could be monitored by the BMV and a separate voltmeter installed to monitor the other.

Worth reading the documentation at BMV-712 Smart - Victron Energy

Agree with this, but, rather than a separate volt meter, perhaps a on/on or on/off/on switch to change between the two banks ?

 

[PaulRainbow]

Yes, I forgot to mention I'm currently lying in Portugal so that's where the cost comes in... I'm renewing my batteries this spring and was looking at AGM for the domestic bank (3 X 100ah). Can I charge AGM batteries from my alternator and will they sit happily alongside my Nav (sealed but not gel, truck battery)?

Thanks for your help.

What's with the Domestic" and "Nav" batteries ?

AGM will co-exist with SLA batteries.

 

[noelex]

The Pico battery monitor is very good and will monitor the voltage of three, or more battery banks.

 

[Buck Turgidson]

The Pico battery monitor is very good and will monitor the voltage of three, or more battery banks.View attachment 151517View attachment 151517 battery banks.

Yep. I have the same and it's perfect for the 3 batts the OP wants to monitor. Haven't looked at prices lately as I got mine 4-5 years ago.

 

[[2574]]

I use Victron Bluetooth sensors to passively and cheaply monitor the voltage on engine and genny start batteries. Easy: Victron Smart Battery Sense

i then use the Victron Smart shunt to monitor the V/A of the house bank with the bow thruster bank as the second line (voltage only) monitor. That is networked to a Cerbo for online monitoring via VRM.

 

[Samarai]

Many thanks to all respondents. I think I know where I'm going with this lo now. Best regards.