Pytes V5 Charge Cycling After Adding Batteries

DIY
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1

Last year I installed a new Victron system using Pytes V5 batteries. The system consists of two Multiplus II 48/5000/70-95 inverters, an MPPT 450/200 controller, and a Cerbo GX MK2. I started with four V5 batteries, then added another two a few months later. Everything seemed to be working fine. Several months ago, I added two more V5 batteries to bring the total up to eight. At the same time, I updated the Pytes battery firmware to the 10.33 version using the BSMQt program. I then started to notice issues. The batteries would go into idle at 98 or 99% instead of 100% as in the past. Also, I noticed when fully charged the batteries would occasionally cycle between discharge and charge.

I contacted Pytes tech support and last week they sent me a new firmware version (10.38) that was supposed to overcome these issues. After installation, the batteries did go up to 100%, but were constantly cycling between charge and discharge. It was like the BMS was trying to balance out the cells, but could not. Thinking one of the new batteries could be defective, I disconnected them, but it did not change anything. To keep the batteries from constantly cycling between charge and discharge, I reinstalled to older firmware (10.33) and now the batteries are in idle at 99%, with an occasional charge-discharge cycle. All the firmware on the Victron devices are up to date.

Pytes tech support is looking into this, but so far has not come up with any explanation or solution. Nor has my installer. So, I thought I would post the problem here to see if anyone else has experienced this or might have a suggestion. Thank you very much for any help you can give.

2

I have 6 units on v33 and had a similar problem. The soc got also stuck at 99% and was cycling between charging/discharging. I did not charge each battery separately to 100% before connecting 4 units to the already installed units. Today I charged each of them separately to 100%. The problem seems to be gone.

3

Thanks for letting me know I’m not the only one. Pytes Tech Support told me today there’s an issue with the firmware not charging batteries added later to 100% and are working on a new version. Last time I checked, my newer batteries were at 98% and this brought the whole bank to 99%. Hopefully they will come out with a fix since there has to be more of us who added batteries and have this problem when they get up to 100% SOC.

4

@Neal Your case is already in process. Our R&D team is trying to find a solution to this problem. soon we will be able to give a solution.

5

My batteries are idle and stuck at 99%.

Charging them separately to 100% didn’t help after all.