BMV Battery Monitor

Need help on how to do Zero Current Calibration on my set up:

Manual says that to do a zero current calibration "ensure there really is no current flowing in or out of the battery" and "disconnect the cable between the load and the shunt, then press 'select"'

What do they mean by "the cable between the load and the shunt"? and is that really enough to ensure "zero current flowing in or out of the battery" in the case of my set up?

I have two batteries. One negative cable (the one being fully monitored, call it the "main" battery) goes to the "bottom" of the shunt and the other battery (the one with the voltage only being monitored) goes to the "top" of the shunt. Then a "common" cable goes off the top to the common ground.

I also have solar positive and negative leads going from my solar charge controller directly to the main battery

Finally, I have bilge pump, gasoline fume detector, Victron MTTP 100/15 charge controller and Blue Seas ACR all with positive leads connected to the main battery before the battery selector switch and with their negatives going to the same common ground as the BMV 712

So in order to do a zero current calibration and "ensure there really is no current flowing in or out of the battery" would I

1. Disconnect the solar source (disconnect at solar panel end)

2. Disconnect the "common" negative feed off the "top" of the shunt.

AND

Do I also need to disconnect the charge controller, ACR and fume detector in order to accomplish the zero current calibration?

thanks!

Hi folks, I am using a BMV-712 to monitor the 12v battery in my Smart electric car. I have installed a sound system and needed a way to determine if the draw from my system was exceeding the car's capacity. (it seems to manage fine)

When the car is running, the car's high voltage 24v battery uses a DC charging system to recharge the 12v battery which controls all the electronics of the car. When the car is off and is plugged in to shore power the charging system also is charging the 12v battery. The charging terminates when the high voltage battery is fully charged. Charging time is based on the high voltage, not the 12v battery, so it is possible that if the 12v was at a low state of charge, and the car charges for 1 hour and stops it will not fully recharge the 12v battery.

I am struggling to understand how I set the parameters of my BMV monitor to accurately tell me the state of charge of my 12v battery.

I can't seem to understand how to determine the tail current required or the float voltage etc.

The battery is a FIAMM 12v (L2EFB) 60ah

When the battery is charging the monitor shows a range of 13.6-14.7v

Our BMV is wired into our 2 leisure batteries and gives a voltage reading of 11.62V. However, when using a voltmeter, the batteries both have a voltage of 14V. Why is there such a large discrepancy?

Hi,

in my boat I've got a BMV 712. It shows my batteries are at 100%soc, but the voltage is dipping to 12,2 this winter. How come it's still 100% SOC with this voltage?

And another question, since the beginning, the BMV is not giving any temperature. Tried flipping the power and the temperature cable (don't see any difference). Is there a way how to get this working

Hi,

I have a CCGX with a VECan NMEA cable. It have a multiple and 3 BMV VE Direct meter plugged in to the CCGX.

I can see some information on my plotter but I do not see an NMEA instance for each BMV plugged in to the CCGX. Is this supported? I also don't see a power out value for my Inverter NMEA device? Is there a document somewhere explaining what NMEA objects and values a GX device will push to NMEA when connected?

I have 2 3kw multiplus. one has a GX and the other a CCGX. Should I add an NMEA VE Can cable to those also or what do I lose by just using the CCGX NMEA link versus connecting the multiplus directly?

Hello,

We are using a setup with 2 batteries 12V parallel, total of 210 Ah. It is fed by the alternator of course and via a Multiplus 800/35 when on shore power. On the system is a BMV-702 and it works very, very good when not using shore power. SOC is very accurate etc. But when in the harbour and switching on the Multiplus, SOC keeps decreasing. Load current of the Multiplus is much higher than the users (only a fridge) so it is not possible that batteries get empty.

I’ve checked the battery-settings in the BMV and also the Shunt and everything seems ok. Software BMV is also up to date.

Anyone got an idea?

Kind regards,

Pim

House Battery Cable Schematis Diagram XLV.jpgI own a 2000 Prevost Marathon Coach Motorhome. The system uses a proprietary communication system for batteries and cabin management. However, this communication system does not monitor anything but voltage and AMP's through 4 each FEM Current Transducers. . I would like to add a Victron battery monitor to system. There are 6 each 4D Lifeline batteries at 210 AMP's each for house. The existing house batteries are wired in 3 each Series producing 24VDC and 3 each parallel producing 12VDC. Attached is schematic of batteries. I just had to replace under warranty the three 12VDC batteries which Lifeline honored do to bad cell bringing all of them down over time. I need a more robust monitoring system to watch batteries . All I see on dash guage is voltages and amps being used. All I see at Inverter panels is Bulk and Float and charging voltages based on battery temperatures and inverter setup parameters. How do I wire in Victron. The Bus also has a 20K generator onboard.

Hi

In my boat I have LiFePO4 cells charged with shore power or SmartSolar MPPT 75/15 (x2) .

When I leave boat for long time I just want to charge up to 80% SOC to extend battery life. To achieve that I figured out that VE.Direct non inverting remote on-off cable (ASS030550310) (x2) connected to BMV-712 would do the trick.

I purchased these expensive cables and configured relay to trigger at 80% SOC. Now I achived desired solar charge cut, but my happiness was short.

As a consequence, the little battery indicator shows that battery is empty already at 80% SOC... Additionaly the time to go is only to 80%. A major set back. Now the BMV is no longer a usable battery monitor...

What can be done? This may be a feature request!

/Peter

ps. I don't want voltage controlled cut of solar charge.

After extensive testing, we found that the SOC is not accurate with Battleborn drop-in lithium batteries. We believe this is due to the fact the Battleborn's internal BMS is not allowing the BMV to take accurate readings.

For example, on a 100Ah battery - When the battery has half of it's capacity drained with 50Ah consumed, the SOC reads 0%. It will remain at 0% as more Amp hours are consumed and pulled from the battery. The SOC will register 1% when it is charged back to only 50Ah consumed, and will increase to 100% once it reaches 0Ah consumed.

Of course it should be a direct relationship for this example - Every Ah consumed should equal 1% in the SOC.

Is the lack of an accurate SOC a limitation of the BMV-712, since it was designed to work with Victron batteries that don't have an internal BMS?

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300Ah LiFePo, 3KVA Multiplus, BMV712, MPPT 150/85, CCGX

The system is 8 weeks old and I have just noticed that the installer has set the tail current to 1%. The general recommendation seems to be 4%. The system has performed 8 syncs in the past 8 weeks. Should I increase the tail current setting?

Hi All,

So this has got me stumped :( I have tried everything else that could possibly cause this issue but think it may be my setup with the charging. So here’s a summary:

I have a 36v Ezgo golf card which previously ran on 6 x 6v Trojan Lead Acid batteries. As a company we have recently got into the solar field so wanted to "experiment" with converting the cart to Lithium batteries as a side project. After quite a bit research I settled on 3 x 12v 108Ah Blue Nova Mobile batteries in series (https://bluenova.co.za/wp-content/uploads/2019/03/BN13V-108-1.4k.pdf).

To cut a long story short we did the conversion and it works brilliantly. Then came the issue of charging. One option would have been to use the 36v charger I already had for the cart. However, my concern there was that the "charging algorithm" on the charger was for lead acid. I did some research on Lithium chargers and found one expensive 36v option. I then got chatting to my Local Victron dealer and he suggested I use 3 x Blue Smart 12v (25A) chargers and install them in the cart permanently wired up to the batteries. What I liked about this idea was that I would be certain that each battery would be charged equally and would never get a battery imbalance (and it worked out cheaper) 12 So I went this route….

Fast forward 2 weeks – cart is going great, no issue and then suddenly battery 2 & 3 turn off (being battery 1 connected to main positive and battery 3 connected to main negative) 1 i.e. the internal battery BMS shuts off… I have gone through COUNTLESS different theories on what could be the cause (from parasitic drain, to wiring etc) but at the moment I’m wondering if the following could be happening (but need someone VERY knowledgeable people to prove or disprove).

So could the following be happening?:

1. Battery 2 and 3 discharge just ever so slightly more than battery 1 during use (as battery one is connected to main positive and batter 3 to main negative).

2. Then during the charging “somehow” the three chargers pick up on when the first battery is full (battery 1 in this case) and then all three chargers move to the next charging phase (say from bulk to absorption).

3. This leads to battery 2 & 3 losing out on just a little of a full charge each charge cycle.

4. In my case the cart is used daily and uses about 30 % in a day. After about 2 weeks maybe that “ever so slight” loss on every charge cycle drops the battery to a low level and the BMS turn off the battery to protect itself?

5. It is a “theory in progress” as the batteries where turning off every few days until I separated the 3 batteries, charged them, put them back in series and then for the past 2 weeks it has been perfect (until yesterday when they shut off again). So last night I separated the batteries again, charged them up and ill see how long they last.

6. So in summary, I suppose what I’m asking:

a. Can you use three of the Blue Smart 12v (25A) charges on 3 x 12v batteries connected in series (i.e. one charger connected to each battery)?

b. In such a setup would they in any way affect the operation of each other?

As a last note, I did install a BMV-712 Smart BUT because of the way the chargers are connected directly to the battery the “input” from the chargers cannot go through the shunt. So its set to reset to a full state of charge at a certain voltage (approx. 42v). This has helps me see what the parastitic drain is (approx. 0.01A) which I think is acceptable. This was verified with a clamp meter.

Any other suggestions would be appreciated 12

Thanks,

Richard

I bought one of these: Victron Energy Wall Mount for BMV so I could wall mount my new BMV but when I connect the VE.Direct cable to the back of the BMV it sticks out about an inch too far to actually mount it on the wall. I bought this so I wouldn't have to drill a large hole in the wall. the VE.Direct cable is the USB type to connect it to a distant VGX. Is there one with an angle connector? I'm puzzled by this.

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I wanted to go to the settings - but the app told me I needed a firmware update before I could do that. So I updated - And then my phone locked and lost the connection.

Now everything is working except for the state of charge.

The product info says that I have the latest (4.3) firmware, so I can not update again.

Is it possible to re-update to fix the problem?

I have a voltage discrepancy in my sistem.

For example, now I read these voltage:

- multimeter = 47.6V

- SmartBMV-712 = 47.04V

- SmartSolar MPPT 250/100 = 47.10V

- VE. Bus Summary for Quattro 48/8000 (on Venus GX) = 46.83V

(My battery is 48 module from Nissan Leaf, connected 6S8P. This is the reason for so low voltage.)

Between battery and BMV shunt I have 1m, and than 0,5m of 90 mm2 cable. Between BMV shunt and solar charge controler I have 1m of 35 mm2 cable.

I read some answers about inaccurate voltage readings, and I connected a cable in my Quattro on Voltage sense. Also, I change the fuse on BMV from 100mA to 2A, but no results.

If the voltage difference between BMV and MPPT is reasonable, the difference between Quattro and BMV is over 0.2V, and the difference from multimeter is huge.

Before Quattro and MPPT 250/100 I own a inverter charger from Taiwan (PIP 4048MS) and a solar charge Midnite 150 Classic with no voltage reading problem at all.

For two days our battery monitor bmv700 has been lit up and flashing between “0200ah” and “ _200 ah”. Its in setup mode. any attempts to snap it back into the regular mode arent working. Pressing + or - or ‘select’ flash up the part of the menu its stuck in “01 ba”. Holding down - or + or ‘select’ just scroll through the whole “01 battery capacity”. Nothing happens when we press or hold ‘setup’. Any advice? We didnt put it into this mode - so wondering if.. a fuse might be gone or some thing?

Hi

I am using a BMV-712 to monitor my 125Ah AGM Super Cycle battery and charging with a BlueSmart IP67 25A charger.

The BMV is telling me that the battery is at 100% when the charger is still in the absorption stage.

My current BMV settings are:

Charged voltage: 13.2V

Tail current: 3%

Charge detection time: 10m

Peukert exponent: 1.14

Charge efficiency factor: 95%

Please can someone tell me if these are correct or what I should change them to. Datasheets and manuals don’t seem to have all the answers.

Thanks.

Hi

I have an installation with a MPPT 110|50 Solar Controller connected to a Venus GX via VE.Direct. I would like to add a battery monitor to this installation however the 24VDC battery bank comprises two banks. Due to wiring and regulation constraints I am going to need to install two BMV-712 monitors and shunts. Can anyone please tell me the best way to connect these two monitors to the GX with the remaining ports I have.

I also noticed in other posts that only one bank would be able to be displayed via the GX using VRM or local access. Is my interpretation of these posts correct ?

Thanks for any help you may be able to offer.

I have had my 702 for about 2 years and I am not sure what my setup parameters should be.
my house bank is 320ah total, 2 flooded 160ah in parallel.
I have attached a screen shot of my setup page.

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What I don’t understand is at what voltage should I synchronize the SOC to 100% and what is zero current calibration?

Thank you.

My BMV712 has stopped working. I suspect the fuse may have gone. What rating is the fuse so I know what to replace it with?

Thanks very much,

Tom

AM Solar has a nice list of recommended settings for Victron products (and not only) including Victron Lithium batteries. Are those good?

I own a BMV-702, a MPPT 100/50 & a Victron Lithium Superpack 12,8V/60Ah. Some of the settings differ from Victron's manuals/specs/defaults.

1. BMV-702 manual only provides two settings specific to Lithium batteries (ch. 6, p.37): Peukert’s exponent at 1.05 and charge efficiency at 99% (those are identical to AM Solar's guide). Other values are defaults for "all batteries":

- charge voltage default = 13.2V (AM Solar = 13.9V for Victron Lithium)

- tail current default = 4% (AM Solar = 2% for Victron Lithium)

- temperature coefficient = 0.0%cap/degC (AM Solar = 0.5%cap/degC for Victron Lithium)

2. Bluesolar MPPT 100/50 manual provides (ch. 3.7, p. 11):

- absorption voltage for LiFePO4 = 14.2V (AM Solar = idem)

- absorption time for LiFePO4 = 2h (AM Solar = 1h)

- float voltage for LiFePO4 = 13.2V (AM Solar = 13.5V)

- tail current default = 2A (p. 9) but is actually disabled when choosing Lithium batteries (knob at setting 7) with firmware 1.46 (AM Solar = 0.5 per 100Ah for Victron Lithium)

3. The 12.8V/60Ah Victron Lithium SuperPack comes without any manual but according to specifications it should operate with:

- absorption voltage = 14,2V – 14,4V

- float voltage = 13,5V (Victron = 13.2V, AM Solar = 13.5V)

- max charge current = 30A (while MPPT 100/50 can deliver 50A, as it name suggests... it's nowhere mentioned/recommended in the manuals but for safety I have limited my MPPT's max charge current to 30A using Victron Connect app).

Question:

So which settings are "better"? Or maybe soome settings (like a higer charge voltage) are better for "performance" while other (lower charge voltage, disabled tail current) are better for battery longevity?

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Source: https://amsolar.com/rv-solar/support

Hello, I have recently installed the BMV702 in an Off-grid solar system in rural DR Congo. But up to now no synchronization has taken place.

I am using a MPPT150/70 to charge 6 12V 220Ah Deep cycle gel batteries, in a 24V system.

So I put Battery capacity at 660Ah. I changed Charged voltage to 28.5 (according to recommendations elsewhere for pure solar systems). Tail current still 4%, at 3 minutes (both unchanged at default values).

I have seen that the voltage reaches and remains at 28.6 no problem. So what could be hindering the synchronization? And what should I do to improve the settings?

Some ideas: Could it be that running charges prevent the sync time or tail current to be optimal? Could it be that the MPPT changes to early from absorption to float hence reducing the voltage?

Kind regards,

Mark

I cannot find any detailed information on the 500A / 50mV shunt used with the BMV-712.

Does anyone have a drawing of the shunt and know what size bolts are used (e.g. M8, M10?).

Hi everybody !
What is the cheapest way to monitor my BMV 712 remotely, over the WiFi to Internet ?

Thanks !

I am adding a BMV712 to my RV and already have a Trimetric. Can I have two shunts inline on the negative cable without causing an issue? Until I am comfortable with the BMV I would like to keep using my Trimetric and then sell it at a later date. Thanks Bill

So I've got an American Diesel Pusher RV with Quattro, CCGX, BV 512 860Ah of LA batteries (12v), the RV currently has solar (8 panels I think) with a third party MPPT charge controller (80A) and an Onan Genny.
The CCGX is connected to a local WiFI network that is internet-connected.

Ultimately I plan to get licensed to tow behind the RV then get an enclosed trailer to tow my pickup behind the RV.

The RV roof is already pretty full so I was thinking that I would have space on the roof of the trailer to add panels, my question is: What is the best way to add these to the system?

a) Run wires from the panels to the RV charge controller?

b) Add another MPPT controller to the trailer and 12v wires to the battery bank?

c) Add a 240v inverter and wire to the Quatrro somehow?

Option c) sounds like the most interesting but what inverter and how do I wire it in?

(Of course, I'd really like to have all of this tied into the rest of the eco-system CCGX, etc.)

I was prompted on multiple devices to update the firmware to 4.03 on our BMV712 so I went ahead. The update was successful but all the history is GONE. What happened? Is there a way to get it back? (Now we don't know how many times the batteries have been cycled, etc.) Thanks in advance. :)

Hi.

I‘m new to this having just upgraded to a bigger camper and have added a 250w Panasonic solar panel, a Victron 100/20 smart controller and a BMV 712 monitor.

Now I’ve added 2 Leoch Pure Lead Carbon 100ah batteries, but I’m lost on the settings I should use; it’s all a bit confusing at first.

Any advice would be welcome.

Andy

My multimeter shows 48.8v. My 702 shows 48.8v but when I connect using the BT app, it says 46.7 consistently

my mid nite charge controller matches the multimeter .

I use the IOS Victron connect app to read my battery information. MPPT 100/30. Used to come up with SOC percentage at top of screen before latest firmware update. Since update, Solar wattage has replaced the SOC percentage. I have to use my Tri-Metric TM 2030-RV monitor mounted inside the trailer to get my battery percentage. Is there any way to change this back to read the percentage on the app?