question

Hi. That voltage should be enough for pylontech for balancing. How ever you can limit charge current to give a few very long charging periods which gives BMS-cell balancing more time to get all cells to equal SOC. As you can see from documentation that voltage limit is done as special 15s configuration.

Have you looked with pylon tech app that what is cell balance status and does your all batteries have same SOC? If that not enough you can once top up all batteries individually to get full top-balanced. If need support you can share diagram and photos how batteries have cabled.

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

My system only charges the battery to 52.4V

When DVCC is enabled, the battery (via the CAN-bms) is responsible for the charge voltage. The Pylontech battery requests a charge voltage of 53.2V. We have however found that in practice this is too high.

The Pylontech battery has 15 cells in series, so 53.2V equates to 3.55V per cell. This is very highly charged and makes the system prone to go overvoltage.

It should also be noted that a LiFePO4 cell stores very little additional energy above 3.45V.

For this reason we opted to override the BMS and cap the voltage at 52.4V. This sacrifices almost none of the capacity and greatly improves the stability of the system.

The battery won't charge to 100%

Also see the question above. The state of charge of the battery is estimated based on the overall voltage and on how well balanced the internal cells are. Because we cap the battery voltage at 52.4V, the state of charge will sometimes rise very slowly once it reaches the mid-90s. This is normal and usually resolves over time.

Thanks for your reply janieronen i am very aware of the reasoning behind these settings but my point is that even victrons own batteries call for 3.55v per cell for balancing reasons (same chemistry as pylontech) even if i connect one individual pack it will still not allow the bms to enter a balancing state at 52.4v like i said the pylontech charge current curve is what really needs to be limited to avoid the high voltage alarm problems the approach taken by victron is not much more than a band aid fix

@Zetecnology

If you check on the GX you will see the battery using DVCC requests a higher voltage than programmed.

The programming is only there just in case and can't hurt the battery.

If you read the pylon batts own manual, the battery balancing is triggered at 90° SOC. (See section on storage) Pylons are not Victron and are not even the same cell type so you can't compare the two at all.

Alexandra no the battery requests a higher voltage than the victron allows, longer term it remains to be seen if it hurts the battery by getting so far out of balance (at a cost to the end user)

and the cell type chemistry is exactly the same with both pylontech and victron so can be compared

i just wish people will not keep quoting inaccurate information