Victron Mp2 with Pytes battery charging behavior

[Sudybua]

Hello,

my configuration:

-3 Mp2 3000

-4 Pytes E-box 48100r-c

In the last days i watched how the charging of my setup behave. I have noticed that the Pytes BMS send a CVL of 56.5V at the end of the charging. (SOC is 99%)

When the Batterie is full it stays in idle for a short time, then it discharges (at 56V the SOC triggers to 100%) to 54.4V. (at this point SOC is 98%).

After a few minutes on 54.4V the re-bulk starts again to 56.5V. The system repeat this 3 times a day when its sunny outside.

Max. charge Voltage is 56.8V and DVCC is on.

My Questions:

Is this behavior normal? Why doas my MP2 dont get into float-mode? Is it better to set the max. charging voltage to 55.2v and let it sit on this voltage a few hours a day?

Best regards Daniel

[OGPS (Ed @ Off-Grid Power Systems - offgridps.com)]

Please show us your DVCC settings and your firmware level. Below are from my system running 10 of the Pytes E-Box 48100R batteries. I don’t see those issues you are having. We are running v31 of firmware as you can see below.

[Sudybua]

Thanks for your reply,

here are my settings:

[OGPS (Ed @ Off-Grid Power Systems - offgridps.com)]

Hi Daniel. Nothing looks wrong, but I do notice three differences. Our FW levels are different, you have a CVL limit of 56.8V set, and you have shared current sense (SCS) enabled. It looks like SCS is disabled under external control. So, try turning off limit managed battery charge voltage and see what changes. I don’t know if that will make any difference. I think re-bulk in the charger settings of the Multi is ignored under DVCC but I’m not 100% certain of that. I would also update your battery firmware. This is the file name for the latest version of firmware for my Ebox batteries: SPBMS16SRPV1.5.29.C16.bin. Firmware on their website is listed as these:

[Sudybua]

Thanks for your help

I will try with your settings.

I updated the Firmware version already to .29.

Do you have the C8 version?

Best regards Daniel

[OGPS (Ed @ Off-Grid Power Systems - offgridps.com)]

All batteries were upgraded to the highest C8 version at the time and then updated to the C16 version after. This was done a couple of years ago. See the document titled “C8 to C16 Upgrade Guide & Firmware”. I think it will depend on the age of your batteries if you can go to the C16 firmware.

[Sudybua]

Hello Ed,

I have the c16 version.

Do you have a mppt from victron and charge on the Dc side or do you have a extern Ac solar?

My brother has a mppt from victron and his system go into float mode every day.

Best regards Daniel

[OGPS (Ed @ Off-Grid Power Systems - offgridps.com)]

I have two Victron MPPT 450/200 and no AC-coupled solar on this system.

[Sudybua]

How look your graph for min/max cell voltages and soc when you get a day where your battery sits a few hours on 100%.

best regards Daniel

[OGPS (Ed @ Off-Grid Power Systems - offgridps.com)]

My batteries haven’t reached 100% for several months but next time they do I will check. It could possibly happen this weekend but that depends if I charge my car at the shop or not

[OGPS (Ed @ Off-Grid Power Systems - offgridps.com)]

Yesterday my Ebox pack hit 100% for the first time in a long time. I worked from home and didn’t charge my car. See below:

[Sudybua]

Thanks Ed,

Your pack seems to cycle as well.

Charge 100% then goes to 3,4v per cell then recharge again.

I thinks its simply the Bms of the Pytes.

[OGPS (Ed @ Off-Grid Power Systems - offgridps.com)]

Here’s another one from today