question

jterrag avatar image
jterrag asked

meaning of the lowest/highest cell voltage with pylontech batteries

Hi.

In the lowest/highest cell voltage fields (with cerbo) before the voltage I always see codes like 0102, 0103 and so on. The rightmost digit always stays between 1 and the number of (pylontech) batteries in my installation, and I only have one group of batteries. So, I simply inferred that, for instance, a 0103 3.318V in the lowest cell voltage field simply means that the battery containing the cell with the lowest voltage amongst alle the batteries (3.318V in this example) is the number 3 in group 1. Hence, the code 0103 does not actually refer to particular cell within a battery but to a particular battery in the whole battery installation.

Also, I assume that the numbering of the batteries within a group starts from the master: so the master of the group is battery 1, the battery attached via canbus directly to the master is 2 and so on following the chain of canbus links.

Can anyone confirm that this is indeed the meaning of the lowest/highest cell voltage (and also of the maximum/minimum cell temperature)?


Thanks

Pylontech
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4 Answers
Alexandra avatar image
Alexandra answered ·

@jterrag

Each battery has an address. Each cell has an address.

A low cell does not always mean the whole battery is low, just the one cell at that address.

Cell balancing starts above 90% SOC so usually (unless the battery has a problem) will not be more than 200mA.

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jterrag avatar image jterrag commented ·
You've answered questions that I didn't ask.

I didn't ask about those codes because I've got problems with cell imbalance or any other problem related to that (crossing fingers...)

But I've got six batteries and the only codes that I see in that page are 0101 0102 0103 0104 0105 and 0106. Hence the question: what is the meaning of those codes? My interpretation seems to make sense but it's just a simple inference. Maybe someone here knows for a fact what those codes mean.


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dirk-s avatar image dirk-s jterrag commented ·
Yes, you are right. First two digits shows the banks. If you have one master and for example 4 slaves it will show 01. The last two digits shows the number of battery in order you have connected within this bank. Master will be 01, the second 02 and so on.

0104 means: first bank and fourth battery within this bank.

It will not give you the detail of the cells within the battery. For this you have to be connected with battery via console port and software like batteryview from Pylontech.

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sharpener avatar image
sharpener answered ·

You don't say what type of Pylontechs you have.

Mine are 3 modules of Force-L2, I believe inside they are very similar to the rack mount ones. Their behaviour is as you describe and is what I have always believed. IIRC there is also a Pylon utility you can download which will give you cell-level detail.

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jterrag avatar image jterrag commented ·

OK, you're seeing something similar. So, since you have three modules I guess you see only the codes 0101 0102 and 0103, correct?


And yes, I've got the utility to "interrogate" each single module to get all the details, I've used it to get the firmware version of each module. As I said above, for now, fingers crossed, I'm not worried about single cells.

I was just curious about those codes that we see in that page and their actual meaning.

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sharpener avatar image sharpener jterrag commented ·
Yes, that's all I ever see.
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kevgermany avatar image
kevgermany answered ·

I've been wondering the same. Perhaps @Guy Stewart (Victron Community Manager) can help.

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jterrag avatar image jterrag commented ·

And I'm guessing that info comes in that very limited way directly from the batteries. That is, the cerbo does not get all the info about all the cells (or even min and max cell voltage for each module) and then decides what to display. I think it does not get anything more from the batteries than what we see (otherwise there would be some dbus, tcp modbus or mqtt way of accessing it).

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Rob Duthie avatar image
Rob Duthie answered ·

Hi All

Just confirmed from Lucas at Pylotech that is the case with these ID numbers, as above, battery modules not cell level issues.

Regards

Rob D

NZ

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