Pylontech unbalanced cells

Question

question

Javier Pardo asked May 27, '21

Pylontech unbalanced cells

Hello everybody,

I have a system with 1 Victron Quattro, 1 VenusGX, 2 Victron MPPT chargers and 12 Pylontech US2000 batteries.

I am currently having high voltage problems in one of my batteries.

I have contacted Pylontech technical support to find a solution, since the problem has not disappeared for about 1 month.

I have sent all the data extracted from my batteries to Pylontech and we have seen which battery is causing high voltage problems.

They tell me that a possible solution would be to disconnect the affected battery from the system and charge it externally for 8-12 hours at 53.2v i 2-3a

Currently I do not have a charger capable of reaching these voltages and amperages and I do not want to buy one to only have to use it once. I think this is a waste of money.

The same Pylontech technician tells me another solution would be "set your inverter in force charging mode" in this way I would not have to buy an external charger.

My Questions:

1 - Is it somehow possible to activate this forced charging mode with VenusGX or Quattro?

2 - What would happen if I disconnected the communication cable that goes from my VenusGX to the master battery of my system? (CAN port)

3 - Would I continue to charge and discharge the batteries through the MPPT chargers or would the system stop working?

4 - Would this be a solution to the problem of cell imbalance?

I would like you to help me solve this problem, since the system works wonderfully, but every day I have the problem of high voltage messages and I cannot solve it.

Thanks in advance.

Pylontech

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Answer 1 · 2021-05-27T16:59:04Z

Rob Fijn answered · May 27, 2021 at 04:59 PM

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

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Javier Pardo commented · May 27, 2021 at 05:17 PM

Hi Rob, thank you very much for your comments.

I agree with you that the best way to solve this problem is to isolate the affected battery and carry out a full charge, as the Pylontech technical service says, but having to buy a charger that I will only use for a single use It seems not fair.

These systems should have a way to fix the battery imbalance without having to invest extra money. If it is a common problem, you should have a solution from the manufacturers that does not imply that the customer has to spend more money. That's not fair.

I am just trying to find out if there is another way to do this without having to buy something that I will never use again, although if this forum does not offer me an alternative I will have no choice but to do so.

On the other hand, I have checked the connections on several occasions and they are all correct, I do not see anything out of the ordinary and the rest of the batteries in the block work perfectly according to the data extracted from them.

I hope I can find a solution.

All the best.

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klim8skeptic ♦ Javier Pardo commented · May 27, 2021 at 05:28 PM

Use 1 of your mppt's?

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Javier Pardo klim8skeptic ♦ commented · May 27, 2021 at 05:42 PM

Hi klimskeptic, I guess this could be a solution.

I should disconnect one of the MPPTs from the Quattro and connect it directly to the affected battery. I understand that there should be no problem with this.

Can MPPT work independently without the help of VenusGX?

Should I disconnect the communication cable from the MPPT to the VenusGX to do this or should I keep it connected?

Just by connecting the output to the battery would everything work according to the configuration in VictronConnect or does it have to maintain communication with VenusGX to be able to work?

It is the only doubt I have right now to be able to do this.

I have never used the MPPT charger to do this and I don't know how it would work.

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Vance Mitchell Javier Pardo commented · May 27, 2021 at 11:09 PM

Personally I would disconnect the victron connect cable so that the mppt only reads the voltage of the battery that you are trying to manually charge.

This way you can completely isolate the faulty battery and charge it seperately to Pylontech's suggestion. Depending on if it is a smartsolar or bluesolar, you might need to adjust the settings prior to disconnecting it.

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Javier Pardo Vance Mitchell commented · May 28, 2021 at 10:48 AM

Thanks for your reply Vance.

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Answer 2 · 2021-05-28T06:33:28Z

markus answered · May 28, 2021 at 06:33 AM

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

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Javier Pardo commented · May 28, 2021 at 06:44 AM

Hello Markus, my installation is connected to the grid, but I do not use the Quattro to charge the batteries, only the Victron smartsolar chargers.

My intention now was to use one of these two chargers exclusively to recharge the affected battery, but there are already two people who have told me that this may not work for the same reason that you are commenting.

Balancing a battery requires maintaining a constant voltage and intensity for a certain time and this I cannot guarantee only with the solar energy that reaches the charger.

In the end I think there will be no choice but to buy an external charger to carry out the operation

All the best.

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markus ♦♦ Javier Pardo commented · May 28, 2021 at 06:56 AM

If you have grid available and a Quattro you already have a good charger ;o)

Why not use the Quattro for that?

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Javier Pardo markus ♦♦ commented · May 28, 2021 at 10:47 AM

It's simple, because I don't know how to do it.

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Answer 3 · 2021-05-28T10:47:12Z

Javier Pardo answered · May 28, 2021 at 10:47 AM

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.

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Vance Mitchell commented · May 28, 2021 at 11:59 AM

No need to apologise, it isn’t wasting time if we can learn from it and possibly help others.

I am also an end user not a dealer, but I have access to a great dealer who is nearly always ready to help and try to work with my unorthodox ideas. A lot of the information regarding Victron equipment setup can be found in the manuals or by signing up for a Victron professional account and going through the online training.

It’s good to hear that pylontech support has been able to help, hopefully you might be able to find a Victron dealer who is also as helpful if you ever need them.

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Javier Pardo Vance Mitchell commented · May 28, 2021 at 12:19 PM

Thank you very much for your words Vance.

The truth is that sometimes you feel like a weird person when you enter these types of forums to seek help.

I don't want my words to be misinterpreted.

My particular problem is that the Victron technician who helped me install remotely on day one is not the person I purchased the components from.

I have not had a direct deal with the Victron technician, it has always been through a distributor and I think this is the problem.

Now, when I have needed help, he has not been able to give me the appropriate solutions as if I had dealt with him from the first moment, without intermediaries.

It is something logical in part, although when you ask for help and you want to pay the price of this help there should be no problems. But when I have had to request his help now, he has not given me all the attention that I needed, nor did he answer the questions I asked him and simply limited himself to trying to solve the problem. For this reason I decided not to continue talking to him, because I saw that he was not going to get the results that I expected.

I agree with you that there are many manuals on the Victron page to learn about everything, but I think we will also agree that there are concepts that escape understanding if they are not explained to you by an expert.

That's where the problem of asking in these forums comes in. Many users assume that everyone who writes here must know EVERYTHING about their system. They think that we are all Victron technicians and when they give you an answer they assume that you will be able to do it without more.

But this is not always the case and many times you decide not to ask out of embarrassment or so that the rest do not laugh at you.

I think this can happen to a lot of people who visit these forums and find answers like "talk to your dealer if you have a problem." So it is difficult to try to learn.

Again, thanks for your responses. I promise that I will inform you of how the problem evolves and if it is finally solved.

All the best.

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Answer 4 · 2021-05-30T13:30:40Z

Javier Pardo answered · May 30, 2021 at 01:30 PM

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.

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sanchuka commented · Jun 01, 2021 at 06:14 AM

@Javier Pardo Thank you for sharing all Pylontech Information, very nice!. Would like to ask you some help on how you can access to BatteryView program and to Pylontech Battery itself and/or with Victron software help.

Did you contact directly to Pylontech? I'm in your position (starting with renewable energy) and have 3x Pylontech US3000. First time I connected I did not set up Venus GX correctly and PV charged at higher recommended voltage or at least that was the info recorded in pictures (58.43V), then I update all Victron firmware (Venus GX, SmartSolar) and set up Venus GX correctly to CAN-bus BMS and everything start working correctly (52.42V) [Multiplus-II is with factory firmware].

About CCL Charge Current Limit (44.4A) versus DCL (111.0A) I'm assuming that it is for Low Temperature (15ºC). As I'm in Patagonia, have not the opportunity yet to set-up 25ºC as I'm Off-Grid in the middle of nowhere.

I'm very interested on how to access BatteryView and see health of my Batteries (i.e. cycle count, general status, others) with Victron or Pylontech Software.

Gracias!, Saludos!, Andrés (spanish language native)

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Javier Pardo sanchuka commented · Jun 01, 2021 at 06:32 AM

Hello @Sanchuka! Pleased to meet you!

I contacted Pylontech directly to discuss my battery problem. They provided me with the software to run tests and check which unit was faulty.

You can contact me at (edited) at gmail.com to talk about this topic. I'm spanish language native too.

All the best

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sanchuka Javier Pardo commented · Jun 05, 2021 at 02:40 AM

Thank you @Javier Pardo I just sent my PylonTech Registration (part number, pictures, others). Do you know If they contact you automatically or I should enquiry an issue in other fill form.

Regards

Andres

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Javier Pardo sanchuka commented · Jun 05, 2021 at 07:21 AM

Hi @Sanchuka

If you have contacted through their website they will forward your email to the person who can solve your problem.

There is no form to fill out (at least I didn't fill it out)

The person who can attend to your case will contact you.

Regards

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Answer 5 · 2021-05-30T20:41:15Z

Rob Fijn answered · May 30, 2021 at 08:41 PM

Hello Javier,

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

This is very good.

thank you,

Rob

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