Auto-Reset SoC to 100% when upper voltage limit is reached

[transistorgit]

Hi,

I have 2 Daly Smart BMS and a SmartShunt. Obviously the dalys are quite bad at current measurements. Altough I could try to calibrate them better, I would like to have the same behaviour like in the SoC measurement of the smartshunt. It resets the SOC to 100% every time it reaches the upper voltage level (I'm not sure how it is labeled there, I think absorbtion voltage).

I can implement it in the daly driver, but think it would be probably an interesting feature for other bms as well? What do the users here think? Please comment.

brgds

[RayTIW]

Hi,

I use the same setup (2 x Daily Smart BMS and Victron SmartShunt)! I would like to see this feature, too!

BR

Ray

[josmeijer]

A remark I must make: if you assume that max_charging voltage = SOC100% you do not account with decaying cells over time., so you might be using a 230 AH battery that has only 130 AH left and might be unpleasantly surprised by an empty battery when least convenient.
I admit this is "Lead-Acid Science" but yet I guess it is something to consider.

[drtinaz]

This would definitely be a welcomed feature.

[Gr33n93]

Hello,

Also, is the warning message from any Daly BMS at below 20% taken into account?

I get every time the message that the charge level is low and then see on the display only the warning message.

Is it possible to configure this message as disengageable?
Since this comes with each discharge daily below 20%.

I myself use 3 Daly Smart BMS and would find the function also important.

[drtinaz]

You might take a look at node red and mqtt. I have instituted a simple flow in node red on my system using mqtt that automatically syncs the bms SOC to the smart shunt SOC when they differ more than a set amount.

[transistorgit]

You can set the warning level by configuring it in the bms itself, using the daly pc master software. The driver just shows what the bms sends.

[Gr33n93]

Thanks for the feedback.
I had only searched for the function in the app and therefore had not rounded it.

[RichieS67]

@drtinaz:
I've been looking for such a flow like this for a long time! I can overwrite the Daly BMS SoC with the Victron Shunt SoC, but a few seconds later it is back to the original incorrect value. Could you please send me your flow? Thank you - Richie

[mr-manuel]

The JKBMS for example resets the SoC to 95% when all cell voltages are greater or equal to OVP (setting in the JKBMS app). So no need for JKBMS at the moment. There is also no possibility to reset the SoC with a command.

[rperpe]

JK BMS user here with same issue; SoC measurement isn't configurable at all and coloumb metering is unaccurate at low currents. Consequence: SoC is getting lower and lower.

As a solution I thought about using another SoC source than the BMS (e.g. the SmartShunt). Is this somehow feasible in dbus-serialbattery?

[mr-manuel]

No but with dbus-mqtt-battery and Node-RED (integrated in Venus OS large) you can mix all values you want

[cokyc]

I use a daly bms and a victron smartshunt.
I would like to sync smartshunt soc with the one read by serialdriver and tried to set soc with node-red.
I wrote, for example {"value": 87.5} to topic W/XXXXXXXX/battery/1/Settings/ResetSoc but do not work.
This topic seems read-only.

[drtinaz]

Something must not be set properly because it is a writeable setting. I do exactly what you are trying to do and I have no issues keeping things in sync.

[transistorgit]

please check the log. I implemented it while using the UART interface and had no problems. Now I switched to RS485 and one of my dalys (I think the one with older firmware) won't accept the setting. You would find a log message like "write soc .... failed"

what interface are you using?

[cokyc]

Hi,
yesterday I was using RS485 and It was not working in any way.
Today I switched to TTL and I think I am doing something wrong (but still I don't know what) in node-red because,
connecting to venus-os with MQTT explorer I can send values to soc correctly but not with node-red.
And with node-red seems I can't send anything to any topic.
I can see the node mqtt-out connected to the broker.

[mr-manuel]

Please share the payload you are sending via MQTT Explorer, the Node-RED Flow and the Payload you see in MQTT Explorer that is send from Node-RED. Maybe you are sending the number as string.

[Markus1301]

Hi,
I want to write the SOC to my Daly BMS. I'm confused about this threat. Do I need your dbus mqqt battery to do this? I saw the pictures of it. Is it a replacement for dbus serial battery or an add on?

[cokyc]

The payload is:
{"value":91}
the topic is:
W/e45f01de751c/battery/1/Settings/ResetSoc

[Markus1301]

Hallo,
I need this, too. It would be very nice, if you could write some more for a beginner, what I have to do here?
Belongs payload and Topic to the "inject". Is payload jason because of the { }
What should I do with the mqtt out. What should I type in "Server"? To I have to install something more, like this dbus-mqtt-battery?

As I said: I little help would be very nice.

[cokyc]

Hello Markus,
As in the picture above, you have to add an injection node where you can delete the timestamp value and keep only the payload value.
Format it as JSON. Set it as {"value":xx} and override the xx with your value. Link the inject node to an MQTT out node.
Set it as in the picture, but change the "e45f01de751c" part with your value (you can see it with mqttexplorer connected to venus-os).
Of course, you have to change the inject node with one where you read the soc from. (for example from a smartshunt or as mr-manuel suggested you can use his dbus-mqtt-battery driver

[Markus1301]

Thank you for your explanation. I don't have a smart shunt, I use my Daly BMS with dbus-serial-battery at the moment. So I looked at dbus-mqtt-battery. There are pictures which look like dbus-serialbattery in VenusOS. Is dbus-mqtt-battary an addon to dbus-serial-battery or is it a replacement?

[cokyc]

ok. Solved.
I had a mistake and I am not seeing it.
I was sending the payload as topic in the injection node.

My bad.

[transistorgit]

Just a small status update:
I implemented the auto-reset-soc on my system, but need to improve my debug logging a bit to make sure it works correctly.

It sets the SOC to 100% when battery status switches to float.
Dbus-spy: Info/ChargeMode

[mr-manuel]

You have to use nightly for the auto SoC reset, since it wasn't released in stable yet.

[Markus1301]

Hi, thanks for your reply. I changed to nightly and there to dev. Now VenusOS says 55,1V. The battery is not charging any more (there are lot's of PV power at the moment). In VRM portal the Multiplus II says: IDLE. On the Multiplus itself the LED absorbtion is on. I never saw the "float" LED on. And the battery is 83,7%, not 90%. So the automatic reset of the SOC doesn't work in my case.

My config.in now is:
[DEFAULT]

; If you want to add custom values/settings, then check the values/settings you want to change in "config.default.ini"
; and insert them below to persist future driver updates.

; Example (remove the semicolon ";" to uncomment and activate the value/setting):
MAX_BATTERY_CHARGE_CURRENT = 70.0
MAX_BATTERY_DISCHARGE_CURRENT = 180.0

; Daly settings
; Battery capacity (amps) if the BMS does not support reading it
BATTERY_CAPACITY = 280
; Invert Battery Current. Default non-inverted. Set to -1 to invert
INVERT_CURRENT_MEASUREMENT = -1

; -- CVL reset based on SoC option (step mode & linear mode)
; Specify how long the max voltage should be kept
; Step mode: If reached then switch to float voltage
; Linear mode: If cells are balanced keep max voltage for further MAX_VOLTAGE_TIME_SEC seconds
MAX_VOLTAGE_TIME_SEC = 30
; Specify SoC where CVL limit is reset to max voltage
; Step mode: If SoC gets below
; Linear mode: If cells are unbalanced or if SoC gets below
SOC_LEVEL_TO_RESET_VOLTAGE_LIMIT = 90

Edit 2: A few hours later. The SOC ist now 99% (53,9V). How can this be. In the config.ini (see above) is SOC_LEVEL_TO_RESET_VOLTAGE_LIMIT = 90. I thought it resets to 90%. Is it the wrong parametet?

Markus

[mr-manuel]

The MultiPlus Float/Absorption LEDs do not correspond to the driver state but shows only the MutliPlus algorithm, even if it's the active one.

[Markus1301]

Thanks for your feedback. One question left: I thought SOC_LEVEL_TO_RESET_VOLTAGE_LIMIT = 90 in the config.ini File will set the SOC to 90% when 55,2V are reached. It goes to 100%. Is this a bug or did I misunderstand something, again?

[mr-manuel]

You misunderstood it.

dbus-serialbattery/etc/dbus-serialbattery/config.default.ini

Lines 79 to 87 in bc267e1

	; -- CVL reset based on SoC option (step mode & linear mode)
	; Specify how long the max voltage should be kept
	; Step mode: If reached then switch to float voltage
	; Linear mode: If cells are balanced keep max voltage for further MAX_VOLTAGE_TIME_SEC seconds
	MAX_VOLTAGE_TIME_SEC = 900
	; Specify SoC where CVL limit is reset to max voltage
	; Step mode: If SoC gets below
	; Linear mode: If cells are unbalanced or if SoC gets below
	SOC_LEVEL_TO_RESET_VOLTAGE_LIMIT = 80

If the SoC gets below this value, the absorption voltage is allowed again. This has nothing to do with the SOC reset.

[cokyc]

why not replicate the behaviour of smartshunt, reset soc to 100% when voltage is xx volt for n minutes.
For example 3.45x16 for 3 minutes.
Or we can put two parameters in config.ini AutoResetSocVoltage and AutoResetSocDuration

It work very well for smartshunt.

[transistorgit]

Actually its the same, as the charging modes are calculated out of the voltages

[transistorgit]

Hi,
I created a pull request for @mr-manuel 's dev branch and he already merged it. So if somebody wants to try...

[mr-manuel]

It was merged to the dev branch of louisvdw and can be installed with the install script.

[cokyc]

Installed yesterday and today have tested it.
It worked but I am not so sure about the timing.
My smartshunt is set to go to 100% after 4 minutes the voltage is over 55.2.
I have MAX_VOLTAGE_TIME_SEC = 200 and MAX_CELL_VOLTAGE = 3.46 in config.ini file.

Smart shunt soc was reset to 100% after 4 min of voltage over 55.2
BMS after about 16 min, so seems the setting in config.ini is ignored and the default 900 sec in config.default.ini has been considered

Here is a graph.

[mr-manuel]

You can check under parameters in the remote console/GUI what's going on. Probably you have linear mode turned on. In this case float is triggered only, if batteries are balanced first. Just check the page at the given time.

[cokyc]

yes I have linear mode on.
Thank you for the explanation.
I will check in the next days.

[cokyc]

I installed the last dev version.
Now I am able to reset soc also in rs485.
But not all the time the soc reset to 100%, because often when the voltage is about 54.6/54.8 the multiplus (I don't know why) goes to absorption and set the charge current about to zero.
Consequently, the max voltage (55.2V) is never reached.

[josmeijer]

The voltage to switch from absorption to float can be freely adjusted in the Victron configuration software. Op ma 3 jul. 2023 17:50 schreef cokyc ***@***.***>:

…

I installed the last dev version. Now I am able to reset soc also in rs485. But not all the time the soc reset to 100%, because often when the voltage is about 54.6/54.8 the multiplus (I don't know why) goes to absorption and set the charge current about to zero. Consequently, the max voltage (55.2V) is never reached. — Reply to this email directly, view it on GitHub <#657 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AIPDJVRPJFLZLXWBZY5ITP3XOLS4NANCNFSM6AAAAAAYJOI3J4> . You are receiving this because you commented.Message ID: ***@***.*** com>

[cokyc]

I already set absorption and float in ve config the same as serialbus driver in config.ini:
absorption = 55.2V (3.45 x 16)
float = 54 V (3.375x16)