With the Pytes V5a, the maximum charging current (CCL) is sometimes already reduced to CCL/V5a = 5A at 65% SOC.
If you then discharge briefly - and then charge again, it works again for a while with a higher charging current.
Initially, my assumption was that this was caused by the ambient temperature - as we have not seen this behaviour with other installations (- but with Pylontech,) I have never seen these problems with Pylontech!
But this happens partly independent of the temperature (min. temp. of the storage tank 13 °C as well as 17 °C, 19 °C, 21°, 22°)
e.g.: System with 3 pcs. Multiplus II / 5000 and 4 pcs. V5a
At 54.23V, 64.4A and SOC 66% → the CCL was reduced to 20A -->> i.e. to CCL/V5a = 5A.
This reduction comes from the Pytes BMS.
It makes sense to reduce the maximum charging current to 90%. (This is also how Pylontech does it)
I have found a temporary workaround:
If you generally reduce the max charging current by Victron to around 20A/V5a, then the max charging current by Pytes is reduced at 75/80/90%.
Is there a workaround?
Is this a known problem with Pytes?
If you generally reduce the maximum charging current through Victron to around 20A/V5a, the charging current through Pytes will only be reduced to 5A/V5a at 80/90%.
You can find this in the Victron settings in the DVCC tab → Charging current limit ON → Maximum charging current XX .
This works better for installations with Pylontech. These also reduce at 90%, which is fine and makes sense.
Unfortunately, the only answer I got from Pytes was:
“Please contact your distributor”…
Another reason to choose Pylontech in the future…
Dear mps
thank you for your help
in my measurement charging current is “only” 16.8A, despite i got this problem
perhaps i node red flow whould help ? Reducing charge current dependence on SOC.
Otherwise i woud waste energy to grid?
I did another interesting measurement yesterday. I had the settings as above. Max charging voltage set to 55V.
Yesterday from around 10:30 to 14:00 it was completely active again within this 5A limit, then even went down further to 1A, SOC was at 62%
After that I deactivated the above setting, i.e. no voltage limit.
From this point on the voltage was increased to around 56.4V, (current 1A) SOC rose to 97% within around 20 minutes and then to 100%
My theory: The BMS was completly wrong about SOC . I’ve only been using the battery since the beginning of February and it was between 20 and 60% the whole time, I think it “learned” again yesterday
If you don’t reach 100% for a while the cells are drifting apart and at the next full charge it needs a while to balance the cells.
During the balancing the charge current gets reduced more and more until it synchronizes to 100%.
I would recommend to disable the voltage limit to let the BMS do it’s job properly.
