Victron BMV-700 settings

[Adam Smith]

Hello

I hope that someone more knowledgeable about battery monitor settings can help me!

I have been watching video tutorials and reading the manual over and over but I still don't fully understand the details. All I really want to be sure of us that I have the correct settings in my bmv-700. Charged voltage, tails current etc. At the moment the monitor is on the default settings.

The battery is a leoch adventurer agm 160ah. Info and Datasheet for leoch agm 160ah is here:

https://www.tayna.co.uk/leisure-bat...8fL8wyhSEqTe184-hrO8wqJgX1gCIiihoCMkQQAvD_BwE



My charger is a redarc BCDC1225 and I am using the alternator and solar inputs. Details of charger below:

https://www.12voltplanet.co.uk/redarc-bcdc1225d-25a-dc-dc-charger-mppt-solar-controller.html

Thank you so much in advance for any and all help that you can offer!

Adam

 

[Adam Smith]

Just too be clear, both the charger and monitor are currently set to default settings for Agm. Does that mean that the settings are close enough or should I tweak them according to the spec of the battery and charger?

 

[Adam Smith]

I should also say that both the battery and monitor are brand new. Should I tell the monitor that the battery has an AH value lower than 160ah?

 

[the1andonly]

I should also say that both the battery and monitor are brand new. Should I tell the monitor that the battery has an AH value lower than 160ah?

With a new battery i would use the given Ah rating. You would derate each year.
As to other settings i dont have such a device so cant help. This should at least bump to top and be noticed again.
So i'll piggy back a question.
Can the bmv7xx trigger a relay at a given SOC?

 

[Raul]

Just too be clear, both the charger and monitor are currently set to default settings for Agm. Does that mean that the settings are close enough or should I tweak them according to the spec of the battery and charger?

Can you post the settings of the bmv and the absorb of the charge controller?

Yes the bmv can trigger a relay on SOC, on voltage, NO or NC. That’s the bmv with the display. The relay is at the back of display, not available on smart shunt.

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[Pausim]

The battery capacity will need to be set 160Ah but I think the remaining default settings should be good enough for an AGM battery.

 

[Hoovie]

I would tend to leave most of the settings as the default, but the battery capacity should be set to 147Ah and NOT 160Ah.
The Victron BMVs algorithm is based on the battery rating at the C20 value. The 160Ah quoted capacity is at the C100 value.

 

[Raul]

Are you sure? The c100 is usually quoted for stationary batteries, but if what you say is right, then the c20 capacity has to be entered to work the right peukert, wich needs changing anyways. The default settings are to optimistic and resets the clock to soon, before the battery is really full.

 

[Hoovie]

Are you sure? The c100 is usually quoted for stationary batteries, but if what you say is right, then the c20 capacity has to be entered to work the right peukert, wich needs changing anyways. The default settings are to optimistic and resets the clock to soon, before the battery is really full.

100% sure.

 

[Hoovie]

Can you post the settings of the bmv and the absorb of the charge controller?

Yes the bmv can trigger a relay on SOC, on voltage, NO or NC. That’s the bmv with the display. The relay is at the back of display, not available on smart shunt.

PS. not to be overly picky, but the BMV-700 does not have a relay that has NO and NC connections, only the BMV-712 has those.
However what you can do is connect up the COM and the NO connections and use the "invert relay" option in the settings to add a bit of flexibility and use the NO as a NC.

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[Raul]

PS. not to be overly picky, but the BMV-700 does not have a relay that has NO and NC connections, only the BMV-712 has those.
However what you can do is connect up the COM and the NO connections and use the "invert relay" option in the settings to add a bit of flexibility and use the NO as a NC.

Do you actually know the difference between 700-702 712?

 

[Hoovie]

Do you actually know the difference between 700-702 712?

Yes, I do.
Do you need to know or are you wondering if I am wrong?

 

[the1andonly]

Well im interested. I believe the 712 is a 702 with bluetooth, 700?

 

[Hoovie]

Well im interested. I believe the 712 is a 702 with bluetooth, 700?

ok. brief summary

Smartshunt - headless SOC monitor, so only accessible via VE.Connect App; 2 inputs (one battery, one more for either starter battery OR temp sensor); no relay, VE.Direct port
BMV 700 - physical display, 1 input only, Programmable Relay with COM and NO (Common and Normally Open) ports, NO Bluetooth; VE.Direct Port
BMV 702 - identical to BMV 700 except 2 inputs (same as Smartshunt)
BMV 712 - physical display, 2 inputs (same as Smartshunt), Programmable Relay with COM, NO AND NC (Normally Closed), Integral Bluetooth, VE.Direct Port, lower residual current draw than the 700 and 702.

The VE.Direct ports can be used for a Bluetooth Dongle (for the 700 and 702) OR to connect to a Venus OS device (Venus GX, CCGX, Cerbo GX, Raspberry Pi). Note that it is an either/or option, NOT both

Personally I would recommend the SmartShunt or the BMV-712 over the 700 or 702 for the typical user as using the BMV display to configure the unit is frankly a right PITA and the extra money is worth it! Being able to use VE.Connect is (IMO) essential with these devices
you can add Bluetooth as mentioned, but a BMV-702 plus Bluetooth Dongle is the same price as the BMV-712, so just get the better one to start with.

If you have a Venus GX device, then you can now use the VE.Connect App via Wi-Fi instead of bluetooth to connect to all these devices.
In that scenario, the BMV-700 becomes a much more user friendly device. When I wanted to add another pair of battery monitors to my setup, I chose to use the BMV-700 option for that reason as I didn't need the features (or expense) of the BMV-712, but I did need the relay option that is part of the BMV range.

I have sold a few Smartshunts and lots of BMV-712s, but I don't recall selling any BMV-700 or BMV-702 units (except to myself )

 

[Raul]

Yes, I do.
Do you need to know or are you wondering if I am wrong?

You not wrong, I was referring to the inverting relay in the settings that gives you the flexibility of NO NC. That’s how you start a generator from the bmv signal.

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[Hoovie]

You not wrong, I was referring to the inverting relay in the settings that gives you the flexibility of NO NC. That’s how you start a generator from the bmv signal.

yup, it is one way.
if you have the 712 you can use the NC directly. And of course if you have the Venus GX or Cerbo GX, you can use the NC as well (that is what I use with the Cerbo to control the Water Boiler via an SSR).

Using the relay function via the BMV display is a right faff though. It is ok as a "setup and leave" configuation but if you want to use it dynamically and adjust or turn on and off according to the situation is, as I said, a PITA. Totally not fun.

 

[the1andonly]

Hypertheical question
Winterization of lithium battery
Could you use a use a bmv 712 to switch a relay on (solar in) at a given SOC then off at at given SoC or would it have to be voltage.

OR SHOULD I JUST PUT AN ISSOLATOR on negative terminal?

Can you pass the SOC data to an Arduino. How to read the bluetooth data, ive controlled the arduino with a phone over bt but not received data.

OR SHOULD I JUST PUT AN ISSOLATOR on negative terminal?

 

[gerry mcg]

Hypertheical question
Winterization of lithium battery
Could you use a use a bmv 712 to switch a relay on (solar in) at a given SOC then off at at given SoC or would it have to be voltage.

OR SHOULD I JUST PUT AN ISSOLATOR on negative terminal?

Can you pass the SOC data to an Arduino. How to read the bluetooth data, ive controlled the arduino with a phone over bt but not received data.

OR SHOULD I JUST PUT AN ISSOLATOR on negative terminal?

i had that Question as well.
if one is not meant to charge Lithium batteries below 0C, and the van is lying outside in winter , unoccupued, so the heating is off and the van is cold / at freezing (or below inside) how does one avoid the solar from charging?
are the Battery monitors built into the Lithium smart enough to prevent cold temp charging, or does the solar have to be disabled to prevent low temp charging?
does one need t warm the van up before allowing charging to start? or will it automatically start one hte battery warms up to an adequate temp? (it will take quite some time to warm up a battery from 0C ambient) no?

 

[Hoovie]

The key thing with Lithium Batteries are they should not be charged* when they are 0C or below, so you need to have some way to prevent that happening from whatever charging sources you have.

1. If your lithium batteries have a built-in low-temp charging feature (some BMSes do, some don't, some claim to but don't in reality) then you are good
2. If the charger has some kind of control line you can use that to disable it via a switch, or via a temperature signal
3. If the charger has built in disabling if temp goes low, you can use that (e.g. Victron MPPT)
4. If the charger just activates on the presence of input power (typical mains charger, most solar controllers, almost all B2Bs or Split-Charge systems) then you would want to disable them by whatever mechanism is available, which may mean adding an isolation switch to the DC line
5. you could deal with 2-4 by having a high-power relay between the battery and all the charging circuit and switch that by some method. that would save dealing with all the individual chargers but for the majority of installations that would almost also mean losing battery power to the habitation as the typical van does not have a "charging circuit" and a separate "load circuit".

*getting into the weeds, you can 'trickle charge' lithium batteries below 0C, but this is usually a feature of the BMS so if point 1. was true you don't need to think about this.
If point 1. was false, then you still need to control the chargers and if grappling with that, adding in features to do current limit charging is not that relevant - except .... solar in the times a lithium battery could be 0C or lower would be likely so poor it would be virtually a trickle charge anyway

 

[the1andonly]

With my particular system the battery bms suspends cgarging at low temps. The votronics Chargers (2 MPPT and a B2B) have individual temperature sensors and also suspend charging at low temps. My view is to control in the 30-80 SOC region.

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[Hoovie]

With my particular system the battery bms suspends cgarging at low temps. The votronics Chargers (2 MPPT and a B2B) have individual temperature sensors and also suspend charging at low temps. My view is to control in the 30-80 SOC region.

Ah, ok. then yes, absolutely you can use the BMV-712 Relay to turn on at a low SOC and off again at a High SOC.
You can't programme it the other way round, but you have the "invert relay" function on all the BMVs and on the 712 you can use the NC output instead of the NO, so whatever kind of control you need to do, you can probably make it happen with the BMV-712

FWIW, I am waiting for the device EPROM to be reprogrammed before I can fit it, but I will have a Disconnect Relay that will be controlled by a combination of Voltage and Battery SOC to disconnect the Lithium Bank from the Lead Bank (and all circuits actually) - and with the SOC setting will be able to choose just how full to charge the Lithium. That could be handy for storage purposes as well as general use.

 

[gerry mcg]

The key thing with Lithium Batteries are they should not be charged* when they are 0C or below, so you need to have some way to prevent that happening from whatever charging sources you have.

1. If your lithium batteries have a built-in low-temp charging feature (some BMSes do, some don't, some claim to but don't in reality) then you are good
2. If the charger has some kind of control line you can use that to disable it via a switch, or via a temperature signal
3. If the charger has built in disabling if temp goes low, you can use that (e.g. Victron MPPT)
4. If the charger just activates on the presence of input power (typical mains charger, most solar controllers, almost all B2Bs or Split-Charge systems) then you would want to disable them by whatever mechanism is available, which may mean adding an isolation switch to the DC line
5. you could deal with 2-4 by having a high-power relay between the battery and all the charging circuit and switch that by some method. that would save dealing with all the individual chargers but for the majority of installations that would almost also mean losing battery power to the habitation as the typical van does not have a "charging circuit" and a separate "load circuit".

*getting into the weeds, you can 'trickle charge' lithium batteries below 0C, but this is usually a feature of the BMS so if point 1. was true you don't need to think about this.
If point 1. was false, then you still need to control the chargers and if grappling with that, adding in features to do current limit charging is not that relevant - except .... solar in the times a lithium battery could be 0C or lower would be likely so poor it would be virtually a trickle charge anyway

Ah, makes sense, thank you.
I've got a victron 75/15 MPPT and I found the temp shut off setting in the app menu.
I've also got a BMV700 with a BT VE Dingle, but I don't think that supports a temp sensor that would broadcast to the MMPT solar controller, so I think it need to change that to a BMV 702/712 if I am not mistaken.
I've not checked my Shunt to see if there are temperature input terminals on it

 

[Hoovie]

Ah, makes sense, thank you.
I've got a victron 75/15 MPPT and I found the temp shut off setting in the app menu.
I've also got a BMV700 with a BT VE Dingle, but I don't think that supports a temp sensor that would broadcast to the MMPT solar controller, so I think it need to change that to a BMV 702/712 if I am not mistaken.
I've not checked my Shunt to see if there are temperature input terminals on it

The 700 has just one input - for the battery. If you want a BMV that supports Temp, it would be the 702 or 712 yes. (or the Smartshunt).
If you want to send a relay-signal to a device (like the Victron B2B) that is controlled by a temperature level then the 702 or 712 would be needed. It would make best sense to get the 712 as you could then send the same "live" temp info to the MPPT (assuming it is a SmartSolar, not a BlueSolar?) via the SmartNetworking feature for (keep the Dongle with the 700 for when you resell it )
If you are looking to just have the MPPT aware of the battery temp, then the Victron SBS - Smart Battery Sense - and the SmartNetworking would be the most cost effective way to go. the SBS is actually only a little more expensive than the Optional temp sensor you would need to buy for the 702 or 712 anyway.

If your primary concern is battery protection against low temp charging, you could consider that the lowest temp a battery will be in daylight hours is probably dawn, when the controller wakes up. If the MPPT controller is near the battery, its internal temp reading is likely to be enough to tell the controller to disable charging. downside is as the battery warms up during the day, the MPPT will not know and charge will be disabled for the entire day regardless.

If I had your setup, I think I would go for the simple, cheap and effective option of the SBS

 

[gerry mcg]

I guess this would work with as a battery temp sensor for the MPPT solar controller along with the BMV700?

Victron Energy Smart Battery Sense

The Victron Smart Battery Sense provides accurate battery temperature data by Bluetooth to your MPPT controller to optimise battery charging parameters.

www.12voltplanet.co.uk

my 75/15 MPPT is a Bluesolar one with the BT dongle, located in the over cab locker in the PVC, with the batteries directly below in teh cab under the driver seat

 

[Hoovie]

I would suggest you have a little check around the internet and places like www.victronenergy.com and their forum at https://community.victronenergy.com to see if there is anything about using Smartnetworking with the VE Dongles that might limit what works?
I remember when SmartNetworking was introduced there were a few 'gotchas' but Victron tend to resolve things quite well so maybe using the Dongle is now no different to the integrated Bluetooth? But never use or specify the non-BT units now so not sure.

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[Raul]

I had a bmv700 with BT dongle networked successfully with other two smart solar chargers and SBS. Network showed all devices. Now the BT is out of the bmv, as I used the only ve socket into RPi. All are plugged on the RPi except the SBS , still on network with the chargers.
I would get the SBS and try first, before you charge to smart.