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bigal avatar image

BMV712 features requests - Edit 2nd battery name, see temperatures

I have installed my new BMV712 and absolutely LOVE it.

The shunt is connected to measure all current coming out of my two GEL banks.

The voltage leads are connected to each of the two banks - house bank 1 and house bank 2.

Therein is my gripe - it would be great to be able (in the app) to rename them (ie House Bank 2 instead of the generic Starter Batt)

I also have the Bluetooth smart battery monitors on the same VE network - again I would like on the dashboard to be able to see the temperatures of the same batteries.

How to make my phone stay connected longer - as soon as the screen locks it disconnects. Change screen lockout?

Is there a way to reset the max voltage reading short of a full factory reset?

Hope this makes sense - would make a great device even better.

Thanks

Al


BMV Battery MonitorVictronConnectfeature request
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Quite agree regarding resetting the max battery voltage. Mine has detected a 20.51 max voltage on a 12V system which was presumably some spike and I cannot reset it. Similarly I'm using midpoint detection but still on the History page there is reference to "starter voltage" and "max starter voltage" both irrelevant items plus not resettable!!

Just FYI, you can reset the history data without a “full factory reset”. There is a menu option (on the device itself) to reset history. Alas it clears all history and it would be nice to clear just one field at a time.

You probably already know, but the “starter battery” monitoring is just voltage. No consumption data of any kind is accounted for on that connection.

Good to know about the reset.

I have the shunt across both house banks so it should give a total amps reading.




Hi Bigal,

by banks do you mean multiple batteries or two separate banks?

If you have two separate feeds on the positive. And relying on an SOC for two banks combined then it will mess with your BMV‘S accuracy in determining soc as the assumed figures in pukerts law won’t be correct. Therefore it could be misleading one bank might be charged another completely discharged and you will read 80% maybe.

Best to have one shunt per bank. Or as intended one shunt for house and the second input for your starter bank (if you have one) starter banks rarely cycle in the same way a house bank does and it’s hardly worth monitoring with a shunt for the time it’s discharging (maybe 20 secs?)

Ps. These new smart shunts look good, I’m looking forward to getting my hands on some! Then perhaps the start banks will get shunts!

Hi Jwfrary,

I have 4 x 6v batteries in series parallel. The have a common -ve but 2 separate +ve terminals run seperate wires to a 1/2/both/off switch.

So to answer your question, yes I have the positive lead from the shunt to one bank, and the starter positive lead on the second bank. I guess this was a bad way to go.


Should I run the shunt positive lead to the both of the 1/2/both/off switch (its almost always left in the both position).


The only issue I can see with this is that other charging sources (alt+solar) are connected to a bus on that side of the circuit.


Al


2 Answers
mvader (Victron Energy) avatar image

Hi @bigal, thanks for the suggestion. I’ll keep it in mind.

In case you have an MFD of a compatible type: there we do support giving each battery voltage reading its own name:

https://www.victronenergy.com/live/ccgx:start#marine_mfd_glass_bridge_integration

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bigal avatar image

This is what I currently have done:



wiring-so-far.jpg (159.1 KiB)
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Bigal,


yep so the way you have it the shunt is not really in the right place. Unless you have the switch set to ‘all’ continuously which sort of defeats the point.

Ideally what you want is a single negative bus bar, everything goes back to there, then the shunt between there and one of your banks. In this scenario you would need two shunts.


now I’m guessing you use one bank for starting essentially and the other for your deep cycle and rotate between them and you have identical banks?

I’m guessing the install is in a yacht?

You might be better served replacing your 1 2 all isolator with a isolator like this.
better still fit it and a cyrix relay. Then you are worry free.


additionally since your Perkins actually takes relatively little to start, say a dedicated agm 30 ah, would crank it no problem, you could combine all of your large batteries in one single bank. Charge them together With your solar and use your shunt on the big bank. Then leave your relatively small battery for cranking. You can always turn the isolator to combine batteries in an emergency in the event of relay or you need to crank.

One great benefits is when you crank, you won’t get the voltage drop effect your other equipment. Also you can use your big batteries to their fullest without worry you won’t have enough cranking power.

I use an oddessy battery victron make some nice little agm batteries which are quite affordable, the. Are also very compact and can be mounted best case very close to the starter/engine for best performance.

Some suggestions anyway

Thanks for the suggestions.

1. Yes the install is on a boat.

2. I should have pointed out that in addition to the two banks in series/parallel (house use only) I have a separate starter battery (start).

Here is a further diagram showing the charging systems (which includes the starter battery).

What modification would you suggest to ensure the house battery is accurate monitored (not worried about starter).

I am thinking I could connect the positive terminals of both banks, and then in the mid point of that cable run a cable to a ON/OFF switch (no need for combine any more). Then the BMV712 positive lead would also go to the common +ve terminal.

sunrise-charging.png (616.1 KiB)

Bigal

ooks good. So you could benifit from midpoint connection and use the 712’s midpoint connection monitoring function. From there you could decide if you would benefit from a battery balancer. We installed one on our large inverter bank and it brought the midpoint voltages to well with 1% where as before when charging we were 3 or 4 percent.

I would always treat your domestic bank as 1 in any case. (Leave your isolator in all position.) then you will get accurate measurements from the BMV for the whole bank. However you should be careful to make sure all your cables are the same length and equall in size/cross section. That will hopefully reduce the potential for unequal voltages across the batteries in the bank while charging.

Jwfrary,

Thanks for the answer. So the way it is currently wired (with the two positive monitoring wires going to each of the two separate house banks) is acceptable? Or should I still be looking to change to a single cable running from the batteries to the ON/OFF switch (which would replace 1/2/BOTH/OFF).

I do like the idea of a single cable + ON/OFF as it would free up the second positive monitoring wire to give me temp.

I think you were right when you initially said that the way it is currently wired, there is probably more amps leaving the battery bank than the BMV is measuring.

Cheers again, just want to make sure I get this right.