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BMV Battery Monitor

Tail Current Questions

HI.

I just installed my MPPT 100/50 and had a couple of questions about tail current.

1.
If the Tail Current dictates when the batteries need to flip over into Float. Why is there an Adaptive Charge setting at all?
I think Adaptive Charge sets the time for Absorb based on a multiplier of the morning voltage of the batteries and Max Absorb Time.
Turn Adaptive off and just the Max Absorb Time is used.
In both instances, Tail Current (if switched on) would flick the batteries into Float mode. But Adaptive mode could time out before that tail current is hit,. Wouldn't that mean that the Absorb time was too short?
With Tail Current available to dictate when the batteries are full, why would you need an Adaptive mode at all?

2.
How does the Tail Current work if the sun goes in and the current drops. Does it just switch to Float prematurely?

thisbigroadtrip asked
Vance Mitchell answered ·

1 Answer

BMV and MPPT settings for Exide ER660

Hi

I have 6 ER660 Exide Batteries in my house bank. Lead Acid. 12V system on a boat.


Battery specs are as follows:

Capacity (each) 140ah (total) 840ah. Do I enter 840ah in BMV Battery Capacity?

20hour is 140ah

Ideal Charge Voltage is 14.4v

My BMV712 is currently set as follows:

Battery Capacity 840ah (is this right)?

Charged Voltage I entered is 14.2

Discharge floor 50%?

Tail current 4%

Charged detection time 3m?

Peukert Exponent 1.24

Charge efficiency factor 80%?

Current threshold 0.10A (I have no idea if this is correct)

Time to go averaging period 3m (again no idea).


I set the MPPTs on Rotary Switch 2. Should I change to user defined and enter the settings to something different from Rotary switch 2 settings?


Highly appreciate any help here.


aelyafi asked
michelg answered ·

1 Answer

VRM Download - columns keep shifting

I am wanting to link a Pivot Table and Graph to downloaded data. But every time I download a new CSV, the column position of the data fields have changed!

Is there any reason why this is happening and is there any way to stop it? it is very frustrating to have to go in and edit multiple columns each and every time I do a download :(


I thought I would provide some examples ....

Went into the download and selected random time ranges, downloaded, then another range, downloaded, and repeated a few times. sometimes the column positions didn't change but usually they did.

Below is a screenshot of three CSV files and a random set of columns, but with some of the data I am needing to extract (Ah consumed, current and voltages)

Columns on bottom sheet shifted one place left compared to top sheet. What is not good at all is that the fields in the middle and the bottom sheets look the same - except they are for different Battery Monitors! - that really screws up the analysis :(

(and note this is just some columns I picked on to show. I didn't check all (around 12) columns I am interested in).

[image]


wildebus asked
wildebus edited ·

0 Answers

SOC does not increase while charging ...

I have a bmv 712. When charging via battery charger/generator, the SOC does not increase. It does show the voltage increase being created by the charger, bot there is no change in SOC. I only know the batteries are charged when the charger shows 100%

4ncar asked
Kevin Windrem commented ·

1 Answer

Using BMV-712 to measure SOC of series connected batteries which are charged INDIVIDUALLY.


I am planning to use a BMV-712 to monitor the SOC of two Battle Born 12-volt Li batteries connected in series to run a 24-volt trolling motor. The batteries are charged individually by 12-volt chargers.

I can find multiple diagrams for using a BMV-712 to monitor:

12-volt batteries wired in parallel, and charged separately,

6 volts in series to make 12 volts and charged with one 12-volt charger.

6 volts in series to make 12 volts, with several connected in parallel to increase capacity.

This is what I have in my travel trailer, which is charged through the trailer system, or can be switched to be charged by a Sterling 60-amp battery to battery charger I can connect to the truck with an Anderson connector. This is monitored with BVB 712.

What I do not find is how to use one (or two) BMV-712’s to monitor series connected batteries being charged individually.

My thinking is this:

I have 12-volt batteries A and B connected in series to yield 24 volts.

Both batteries A and B are charged individually.

Connecting to measure both batteries:

If I connect the BMV shunt between the negative terminal of battery A and the trolling motor, the shunt will detect the energy supplied to the trolling motor by BOTH battery A and B, but will only detect the energy charging battery A. With each use and charge, the calculation of the SOC will be off by 50%. The only ways I can think of to compensate for this is to adjust the peukert exponent to be about .52, or the charging efficiency factor to about 200%. The ranges shown in the manual do not include these drastic settings so I doubt either is possible.

Connecting to measure ONE battery of the pair.

If I connect the BMV between battery A and B the shunt measures the current flowing from battery B to battery A. When charging, the shunt will measure the energy used to charge battery B. The SOC should be accurate for battery B. Batteries A and B are “matched” per Battle Born- and under the same load from the trolling motor, so the SOC of A should be very close to battery B.


Is there a way to measure the SOC of both batteries?

Is there a better way to measure the SOC of one of the batteries?


The rest of the story:

I have two Battle Born 12-volt 100 AH Li batteries connected in series to produce 24 volts to run a trolling motor. The batteries are charged individually by two different systems. The primary means of charging is a Dual Pro charger (15 amp per battery) The batteries will also be charged by a Minn Kota MK-2-DC onboard alternator charger. Its output is up to 10 amps per bank with a 25-amp alternator, but my outboard only puts out 20 amps.

It would have been simpler to have two 24-volt Li batteries in parallel charged by 24-volt chargers- but that is not what I have…


hednout asked
hednout commented ·

1 Answer

Voltage for ground relay information wrong in manual ?

I have a Multiplus 24/5000/240 and an Autotransformer. According to the Autotransformer manual the Relay is 12 V, and the output voltage of the Multiplus/Quattro is also 12V regardless of the DC Voltage of the Inverter. Here is what it says in the manual

When the Internal ground relay is not selected in VE Config or Victron Connect, there is 12V on the external terminal of the Multi/Quattro for the ground relay control (on all models 12/24/48V this voltage is 12V).

However if I measure the voltage I get the DC Voltage of my system (in my case 27V) and not 12V. I am afraid this will burn out the coils on the Ground Relay in the Autotransformer.

mfriedel asked
mfriedel answered ·

2 Answers

Updating BMV history

There is a similar question posted (https://community.victronenergy.com/questions/38295/bmv712-firmware-update-cleared-the-history-can-we.html), but my question is a little different.

I don't want to recover any history, but just want to update the history with specific settings (value for Charge Cycles and Total AH Drawn specifically). I have changed the BMV fitted to the battery bank and would like to be able to transfer these values over to keep the usage accurate.

Is there any way to manually change these entries? (I want to update a BMV-700. I can access via Cerbo as well as display itself)

wildebus asked
Paul B answered ·

1 Answer

BMV & SmartSolar Streetlight to warm battery box

Hi, I have a 190ah LFP battery going in to an ammo can which will be in my truck bed. I'd like to heat the box using small ~25w heat strip(s) when the battery is too cold to charge, but only if it was going to charge in the first place.

What I mean by that, is that if it's the middle of the night and below freezing, don't bother because there's no sun to charge with anyway. Similarly, if I have a foot of snow on the panels and it's freezing outside, don't bother because the panels might not even produce enough voltage to initiate a charge cycle.

I was thinking some combination of the street light function, load ouput, and BMV low temperature relay setting could accomplish this. Likely easily with the ability to invert the streetlight functionality but I do not think that's possible from my research. Maybe some NC relay that the streetlight triggers when it'd normally be operating an actual streetlight (night?)

Any ideas appreciated!

hour asked
Paul B answered ·

1 Answer

Midpoint Voltage not accurate

[image]

martinkeogh2 answered · 1

I was successful measuring the mid point on my 12volt house battery system (2 × 6volt Batterys in series) up until yesterday. Now they are not reading accurately. 2 volts lease than actual. I have also try this on my start battery (24 volts) and this input is measuring 5 volt less than actual.



martinkeogh2 asked
Paul B edited ·

1 Answer

BMV 712 False reading after dead batteries?

I recently had my RV in for service. It was there for about 18 days. I must have left the water pump on by mistake. When I went to pick the RV up the batteries were completely dead. The "phantom load" (Propane detector, radio, etc.) should not have depleted 180 Ah of batteries. My guess is the water pump kept cycling till the batteries were dead. When I hooked up to shore power after about 15 minutes the BMV said State of Charge was 100%. I know this can not be correct. Is it possible to get a false reading on "dead" batteries, or are my batteries "dead" and no longer accepting a charge? I know you are not suppose to let Lead Acid batteries go below 50%. Can a 1 time complete discharge kill the batteries. Any info and tips would be appreciated.

donaldn01 asked
Kevin Windrem answered ·

3 Answers

Torque for lithium batteries

I have new 200ah lithium batteries I torqued to 19ft/lbs but worked lose

What’s correct setting

Thanks

sea1ravdn asked
Stefanie answered ·

2 Answers

Ladung wird nicht richtig angegeben

Hallo,


ich habe ein Problem mit der Feststellung des Ladezustandes des Akkus.

Zur Ausstattung:

  • Victron Blue Smart IP22 Batterieladegerät Bluetooth 12/30 1
  • Victron Battery Monitor BMV-712 Smart
  • und in Zukunft auch Solarmodule.


Ich lade den Akku, sobald ich Landstrom habe, da wir die Solarmodule noch nicht installiert haben. Am Akku habe ich eine kleine Last 5- 7W, die ständig läuft. (LTE-Modul, RASPI) Nun bekommt der BMV nicht mit, ob der Akku geladen wird. das bedeutet, dass auf Grund der Last die scheinbare Batterieleistung stetig nach unten geht. Obwohl der Akku voll ist, habe ich nun eine angegebene Ladung von 0%. Entweder fehlt mir noch etwas oder ich habe etwas falsch geschaltet.

Es wäre schön, wenn jemand eine Idee hat, denn so kann ich das System nicht nutzen.


Viele Grüße

Jens

jenswa asked
jenswa commented ·

1 Answer

Why does "Limit Inverter Power" work, but "Limit Charge Power" does not in ESS?

I am running a MultiPlus with ESS Assistant installed. I had charge current set to max in VEConfigure, but had Limit Charge Power turned on in ESS, along with Limit Inverter Power.


This had been working just fine until I had to remove the BMV-712 temporarily. When I did this, I turned on the Battery Monitor option in VEConfig for the MultiPlus. I set the Battery Monitor in Venus OS in System Setup to the MultiPlus. However, now whenever charging occurs, it is at the maximum current, not what I have set Limit Charge Power to. Can anyone explain why this does not work with the MultiPlus Battery Monitor, but Limit Inverter Power does?

ee21 asked
chuff answered ·

2 Answers

Wiring a Victron Battery monitor 702 - another question

Hi All

Thanks to those of you who responded to me regarding my previous post. Unfortunately I had posted an incorrect diagram - that caused some confusion - I have reposted the correct diagram here. Apologies I am not even an amature electrician!

Questions:

1) I assume I can still attach all black wires from house to shunt battery only

2) Then all black from start battery to Loads and Chargers

3) then included red wires to shunt/red terminals of batteries as indicated

4) confused through about black wire that goes between black house and black start (in diagram) - feels like that would circumvent shunt if connected to both Battery Only and Loads and Chargers as per above?

5) will switching system still work?

6) I have a battery voltage meter for both batteries - might it be an option to just put Victron on House? If I did - do I leave the black cable between battery on shunt and black on start? Again - feels wrong.

7) will charging system still work - from engine alternator and 20A charger?

Thanks all - really appreciate the support!!!



kaz asked
kaz commented ·

1 Answer

No BMV 712 history, inverter shows low voltage protection

Hi all, I've asked a similar question before, but after doing some trouble shooting, I still have an issue I'm trying to solve for. I'm converting a Ford Transit 250 into a camper and just finished setting up my electric system last week.


Components:

BMV 712 Smart Battery Monitor

MPPT 100v 30A Solar Charge Controller

(3) 100Ah LiFePO4 Battle Born batteries

Giandel 2200W Pure Sine Wave Inverter

Sterling 60A B2B Charger

Progressive Dynamics 60A 12v LiFEPO4 Battery Converter/Charger


What I’m trying to solve for is that when I turn my inverter on, it beeps continuously and says "Lo", indicating low voltage protection, and then shuts off.


I have taken apart the inverter and checked that the fuses are in good shape. (There are 4 30A fuses and they are all good).


I have charged up my battery bank to full, using my PD Converter, and synchronized the SOC to 100% on my BMV 712, as well as input the correct battery monitor settings in the Victron app.


It was previously recommended to me that maybe my main 300A fuse was blown, or that there was a short somewhere. I have used a multimeter to test all connections and I’m getting consistent voltage of over 13v anywhere I test. That leads me to believe that there is not a short, and that the 300A fuse is not blown (I've tested on both sides of the fuse).


However, my BMV 712 will not show any history (please see my updated attachments).


What am I missing here? Does anyone have any suggestions?


joycarlaina asked
joycarlaina commented ·

2 Answers

Max Length of BMV 712 UTP Cable

What is the max length of the UTP cable for the BMV 712?

Other than having an RJ12 connector with all 6 wires in a straight through configuration, are there any other requirements for this cable?

svsimple asked
wkirby commented ·

5 Answers

Lynx Shunt VE.Can Installation and Wiring

I am aware that a new Lynx Shunt VE.Can is initially set up to have the battery distribution to its left and the load distribution to its right. Is it possible to modify the Lynx Shunt to allow for the battery distribution to be on the right instead?

I am wondering if changing the position of all or some of the five sensing wires inside the unit would allow for changing the location of the battery distribution. If it is possible, which wires need to be moved and to which positions? If this is not possible by physically moving sensor connections, is there a software setting that could be changed?

My system is currently set up with the battery distribution on the right side of the Lynx Shunt. Based on my VRM portal reports the shunt is measuring the current flow in the opposite direction for how the system is connected. As an example, if my battery bank (9.6kW capacity) SOC drops from approximately 100% to 21% and my inputs are 1kWh from the grid and 21 kWh from the PV array, the VRM is reporting my consumption as 15kWh. Based on those input numbers (which I assume are collected directly from the Multiplus and MPPT), I think that the consumption number should be around 29kWh.

My system is:

8 x Battleborn 12V LiPO batteries (configured as a 24V 400Ah bank)

2 x Multiplus 24/3000/70

1 x SmartSolar MPPT 150/85

1 x Orion 24/12-70

2 x Lynx Distributor (used on battery and load sides)

1 x Lynx Shunt VE.Can

1 x Cerbo GX

1 x GX Touch 50

@Matthias Lange - DE @mvader (Victron Energy) @Daniël Boekel (Victron Energy Staff) - user overview - Victron Community

warren-b asked
sarahb commented ·

1 Answer

Midpoint Voltage not accurate

my BMV is reporting a 25% midpoint deviation on 2x NEW Trojan T-105 batteries. when I grab the voltmeter and check while connected I show 6.4v and 6.5v. when I disconnect the batteries they show the same 6.5v. The TOP of that spike is when I checked while connected. voltmeter was NOT showing 9V and 5.5v.

Any ideas?

[image]

p0lar asked
martinkeogh2 answered ·

2 Answers

bvm 712 Monitoring midpoint of a lithium battery bank

Hi I have 2x 100amp Lithium batteries set up in parallel see attached pitcure I've created. Is this the correct installation for the monitoring cables from battery to Shunt?

casablanca asked
Kevin Windrem answered ·

1 Answer

BMV 600 showing high variance in consumption

My BMV 600 is showing consumption jumping from up and down around 10 amps within seconds. Even after after having used the "Zero" command and before connecting any load it jumps up and down. I have tried resetting to catory defaults, but that doesn't seem to help. Problems occurred after installing extra battery pack for a bowthruster that is linked to the main battery pack through a Citrix Battery Combiner on the plus side. I'm wondering if this disturbs the readings?

I already checked the thread "BMV-600s showing impossible high consumption" but the steps proposed there did not solve my issue.

Any Suggestion or do I simply need a new shunt?

Thanks in advance

Søren

nexus asked
Matthias Lange - DE commented ·

1 Answer

VE.Direkt cable from BMV 602S for BMV 712 Smart

Good morning everybody,

I would like to exchange the BMV 602S for the BMV 712 Smart.

The question I have is:

Can I use the existing VE.Direkt cable from the BMV 602S for the BMV 712 Smart?

jjm asked
jjm commented ·

2 Answers

Charge starting battery: BMV 712 relay vs MPPT SmartSolar Load Output

I have an older PWM charge controller which will charge both the House and Starting batteries. I am getting more solar panels and want to upgrade to MPPT, but MPPT charge controllers generally do not support 2 battery banks.


  • Assume I start with a single MPPT SmartSolar or BlueSolar controller


What would be the best solution?

  1. I could use the Load Output and wire that directly to the starting battery, and set a rule for the Load output to turn on the load when the house battery is between X and Y volts. Pros: doesn't require more equipment. Cons: the bigger MPPT controllers don't have the Load output at all, so I'd have to stay with the lower capacity models.
  2. I could get a BMV 712, and use its relay output to control a relay which connects the House and Starting batteries, and use a similar voltage-based rule (On between X and Y volts)
  3. Some other Victron product - battery isolator or combiner or...?


Thoughts?



xmd asked
xmd commented ·

2 Answers

BMV-712 Connection - 3 battery banks (House, Port & Starboard Engines)

Hi All - I have reviewed a lot of post - but still have a Question regarding how to connect BMV-712 when you have 3 batteries (House, Port & Starboard Engines)

I have borrowed some images (thank you Rob Howdle https://community.victronenergy.com/users/1046/pjbfsc.html) to illustrate current system layout as per illustration #1 below

I believe this is the correct circuit as per Victron recommendation (and as per illustration A from another chat on this forum). However, I have the following questions - and would really appreciated some feedback - cheers;

Q1: Is illustration #1 the correct way to install BMV-712; or if I wanted to measure HOUSE then could i just go with illustration #2 ( and not use the Main DC Ground Buss)

Q2; I think I understand that the BMV-712 will only measure Load A and calculate State of Charge for HOUSE battery (thanks Paul B) https://community.victronenergy.com/users/1046/pjbfsc.html

But what about Load B/Engine Start PORT and Load C/Engine Start STBD; will this NOT be considered (or interfere with BMV-712 calcs) - what happens when I start PORT Engine; or run the fridge that is current Load B.

Q3: If I choose to connect Load B and C (other than Starting) to HOUSE, I assume I will need to definitely use the Main DC Ground Buss ?


BMV-712 Connection #1:

[image]


BMV-712 Connection #2:

[image]

Illustration A: bmv.pdf

[image]

peter-gillie asked

0 Answers

Can we bolt busbar onto 2000A shunt?

Can we remove the supplied bolts from the 2000A shunt, place our copper bus bars over the holes on battery and load side and use new, longer stainless steel bolts to fasten the busbars to the shunt?


Ps. This is for a 135kVA system with busbars running the length of the wall - batteries on lower side and loads on higher side.

warwick asked
warwick commented ·

2 Answers

how to reduce/split a large GX data log file of 2GB (70MB Ziped) so can be up loaded to VRM portal.

Hi I have a GX data log file of 2GB the I would like to load to VRM.

Ziped it is still 70MB which is above the 64MB limit.
swisssolar mentioned that he split the file. can any body tell me how to do this?

Cheers Jon

jon-lowbank asked

0 Answers

Smart shunt not reading current

I have a Smart Shunt 500a connected directly to the negative terminal of my battery from “to battery minus” side of the smart shunt. (There are no bus bars or other items between battery and smart shunt.) The “to system minus” side of the smart shunt is connected via a bus bar to the Victron multiplus box, dc distribution box and ground. As far as I can tell, the system has 2-3a coming in from shore power (this is based on a reading from my EMS box). All ac and dc circuits are disconnected, so I’m assuming the battery is charging. Current voltage on the battery is 14.38. I am reading through the smart shunt 0a, whether I am testing items on the dc circuit or just charging. Shouldn’t there be some amount of current reading?

jbyers281 asked
goodoz commented ·

1 Answer

BMV 712 SOC reads "--", Inverter reads "lo", No BMV history

I'm converting a Ford Transit 250 into a camper and just finished setting up my electric system last week.


Components:

BMV 712 Smart Battery Monitor

MPPT 100v 30A Solar Charge Controller

(3) 100Ah LiFePO4 Battle Born batteries

Giandel 2200W Pure Sine Wave Inverter

Sterling 60A B2B Charger

Progressive Dynamics 60A 12v LiFEPO4 Battery Converter/Charger


I've been reading forums and doing a lot of research and can't figure out why the Battery Monitor state of charge just shows 2 dashes (--), and there's no history (Deepest discharge - 0Ah, Discharged Energy 0.0kWh, etc.). It's been this way for about a week now.


Also, when I turn my inverter on, it beeps continuously and says "Lo", indicating low voltage protection. Yet my 12v system runs and works fine (water pump, lights, fan, etc.). But when I turn the inverter on to use my GFCI outlets, they don't work. And again, I can't tell what my SOC is.


I've gone through the battery settings in the Victron app and changed everything to the recommended specs (see attachment).


Could anyone please point me in the right direction?


Thank you!

[image]

[image]

joycarlaina asked
joycarlaina commented ·

1 Answer

Proper cable wiring for BMV 712 shunt and MPPT on parallel LFP batteries

My boat’s house bank has 2 100AH Battle Borns wired in parallel and I’m installing the BMV712 smart shunt today. I will connect the “battery” side of the shunt to the negative post of the “back” battery. The loads are going from the “front” negative post of the other battery to a bus bar. In my previous house bank I had always connected the positive lead on the MPPT and plug in charger to the front positive post and the negatives of the MPPT and plug in charger to the negative post of the back battery for balanced charging. If I keep this configuration with the new LFP house bank will it interfere with accurate readout from the BMV712?

randy-putnam asked
Paul B answered ·

1 Answer

BMV-712 Not Working

As part of the purchase process I had the dealer I bought my Tiffin 32SA from add in a Victron BMV-712 battery monitor. I did not check it when I picked it up. It does not seem to work, there is nothing on the screen. It has never worked. They wired both positive wires(B1 and B2) to the same battery post. Don't know why they did that.
I have removed both of these one at a time and tried them in each position, nothing happens. Both of these wires test out at 12 volts. I have tried both the included telephone cable as well as one I have here at home, no change. It does not show up on the Victron Connect app.

newps asked
Alexandra answered ·

1 Answer

Multiplus 12/3000 low Bulk charge voltage and amps

My Multiplus is limited to 13.39 volts while in Bulk and Amps are limited to around 14 or so with the batteries at 85% charge. I just started the multiplus so it has not been in Bulk but just a few minutes. It did go to 115 amps current for a short time then cut back to the 14 or so quickly.


I have 500 Ah LiFePo4 batteries and the the multiplus is set to 14.5 volts Absorption and 13.6 volts float. It is set to 30 amp input current and 120 amp charge current. I used the Victron Connect app to program which I don't believe has an assistant option to check.

Why is Bulk voltage lower than Float voltage? This is barley the resting voltage of the batteries.

dockthis asked
Alexandra edited ·

1 Answer

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