question

Hi Javier,

In my opinion I think it is best to take that one battery out and charge only this one. You have an expensive battery bank. You do not want one bad battery in this.

If the cause is that battery, they you will find this.
Check also the battery connections of your whole system to find a possible cause.

Please let us know how this is going. I am interested to know.

Regards,Rob

Hi @Javier Pardo

Do you have a grid tied installation or is your site offgrid?

If the imbalance of the battery cells gets too big, it is pretty impossible for the battery to rebalance the cells in normal operation.

Usually a balancing takes place with <1A only and only if the battery gets close to fully charged.

So if you stay in partially discharged state for longer time, cell imbalance can happen.

You can help the battery to balance the cells by charging it to that point were the cells begin to fade and then limit charging current in DVCC menu to 1A.

But this can take quite some time. It depends on how imbalanced the cells are.

If you are offgrid, you might not have the carging source available long enough.

BR

Hi Vance, thank you very much for your reply.

Finally I have decided to buy an external charger to charge this battery.

It is difficult to explain this, but when you are an end user things are not as easy as it seems.

I've been trying to find a solution to this problem for almost a month. I speak from the point of view of an end user who, until recently, knew nothing about photovoltaic energy and that my knowledge in this field is limited.

I first asked a Victron dealer for help. The only solution it gave me was to limit the charging voltage on the DVCC, but the problem persisted. I did not want to insist more because this distributor did not seem very willing to waste much more time with me.

Then I contacted Pylontech to see if I could find a solution.

I have to say that the technical support from Pylontech is incredible. These people are willing to help you in everything and they answer in a very fast and efficient way. I am very happy to have a product from them just for this reason.

The Pylontech technician at first recommended that I use an external charger to solve the problem, since it is the most exact way to transmit the necessary voltage and amperage for a long time and for the cells to balance.

Then he tried to give me another solution to avoid spending money on an external charger. Activate the option to keep the batteries charged in VenusGX for several hours.

The problem is that this option to keep the batteries charged is not activated on my system. As I said before, my knowledge is that of an end user, I am not a Victron technician. The technician who performed my installation did not put this on my system. Of course, I do not dare to configure anything if I do not really know what I am doing or someone gives me the appropriate instructions to do it without danger of spoiling anything.

I have read that this option is found within ESS systems, I have tried to read manuals and try to understand how everything works, but without a person behind to ask and clarify concepts this is impossible.

I understand Victron's policy not to support end users. They want to keep their quality standards very high in their products and it is a good thing for me. But not all of us have the possibility of obtaining help from a Victron technician when we need it and that is why we try to resort to these forums in search of a light that illuminates the way.

It's kind of complicated, I know.

Tomorrow I will receive the battery charger and I will try to charge for 12 hours.

Then I will follow the instructions from Pylontech to update the firmware of the BMS and see if the problem is finally solved. If not, I think it only remains to pray.

Greetings and thank you all for trying to help me and wasting your time.

Hello again. I want to make a small update of my case for those people who may be having the same problem.

Tonight I have made a charge of the affected battery using an external charger.

Charging started with the battery at approximately 40% charge.

The current used throughout the process has been approximately 2.5a.

It has been charging the battery for 18 hours.

I have reconnected this battery to the rest of the batteries when they were at approximately 80% charge.

I have disabled the option to limit the voltage from VenusGX to let the system charge to 52.2V as stipulated by Victron.

Normally the high voltage alarm appeared when reaching 97% of the SOC load, but for now it has reached 100% and no alarm has appeared.

On the other hand, I also had problems with an "internal error" alarm on another of the batteries. Apparently this alarm is due to a failure in the BMS firmware and must be solved by updating to the latest version.

Once all the batteries have been connected in bulk, I have updated the firmware to its latest version. I have done this with the BatteryView program provided by Pylontech technical support and the 2.1 firmware that they have provided me.

One note that I must make about updating and obtaining data from the US2000C batteries is that the connection cable to the console port must be made with the RJ45-DB9-USB scheme. On the Internet there are many messages that talk about the RJ11-DB9-USB connection for US2000 batteries, but in this case the connection to the battery port must be done with RJ45 no RJ11.

At the moment I cannot guarantee that the problem has been solved, although no problem has appeared today. I am going to wait for the batteries to discharge up to 30% tonight as I usually do and tomorrow to carry out another full charge to see if the problem has disappeared.

All the best.

Hello Javier,

Thank you very much for sharing your experience and finding what you have learned.

This is very good.

thank you,

Rob