question

lazza avatar image
lazza asked

12 x Pylontech US3000 with hub (6+6) BMS not communicating CCL correctly

We have just installed 12 x pylontech US3000 with a hub for 2 racks of 6. The BMS is correctly communicating the DCL, but not the CCL. The CCL and DCL should be equal and the CCL is exactly half that of the DCL, which makes me believe that the BMS is only communication the CCL of one rack, not both. (cant be temperature issue as we are at 30ºC here)

This poses quite a problem. I have already noted that, although the Pylontech website and suppliers say that the US3000 can go up to 12 batteries without a hub, this isnt the case. If you do this, only 8 will be recognised by the Master (exactly the same as the other models). Therefore a hub is required.


I hope this CCL issue isnt another error!! Has anyone else heard of this issue? Is there a work-around?


Thanks

Pylontech
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5 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Have you cycled the batteries a few times?

They are probably just a little imbalanced and some are full, while others can still take charge.

Do a few full cycles and report back with the data from VRM, specifically side by side the BMS Charge and Discharge limits, and the SOC in the Advanced section.

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lazza avatar image lazza commented ·

Hi Guy

not sure if I responded in the right place, did you see my reply?

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Mikael avatar image
Mikael answered ·

Hi

I see the same behaviour when the battery is gett closer to fully charged. I only have a single Pylonthech US2000. So I have assumed that this is how it should work.



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lazza avatar image lazza commented ·

that's reassuring. thanks.

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lazza avatar image
lazza answered ·

HI Guy, thanks for the quick response.

Here's a copy from the last few days since the problem ocurred. This has confused me. It seems that the CCL varies from 177.6A during the day then shoots up to the expected 444A at night---- what might the explanation for this be?


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CristiMV avatar image
CristiMV answered ·

In regards to powering the LV Hub....have you supplied power directly from the batteries, or used a separate 48v power supply? thanks

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mito avatar image
mito answered ·

I have the same issue with Multiplus 2 and UP5000 and US300C battery banks, DVCC and BMSCAN comm.
Pylontech BMS algorithm changes CCL at both ends of SOC, <5% >90%, so it decreases CCL in order to protect battery at the SOC extremes. So far I don´t see any way to change this from Victron side if you are at DVCC. BMS disregards whatever Charge Current parameter in VEconfigure.

In our offgrid systems, these behaviour poses a problem because when diesel generators are the main source for charging batteries. Reason is that when BMS decrease CCL at high SOC, at the end means Generators work at low effciency areas and take more time to charge batteries, both factors mean more operating $$.
The only way to overcome this Pylon BMS behaviour is establishing maximum and minimum SOC parameters to limit at 90% and 20%, what at the end means keep batteries life at maximum at the expense of reducing the available stored energy for loads.

If anybody has a better idea will be welcomed.

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