Congratulations.
Please tell me: The Operation Manual of the PylonTech US3000C battery states that the recommended charge/discharge current is 37 Amps. We will not talk about short-term current values - it is clear there (Max Charge/Discharge Current: 90-200@60sec, Peak Charge/Discharge Current: 90-200@15sec).
What is the BIGGEST NORMAL value of “Charge/Discharge Current” in Amps that can be taken into account and allowed?
If I have two identical batteries connected in parallel, what is the HIGHEST NORMAL charge (and discharge) current I should use?
60A per battery for both charging and discharging.
But I would go with the recommended. It’s better in the long run.
Here is some performance test made by Pylontech on its PF25N cell.
So the above 60A figure is the 0.8C from the cell capacity of 75A, below which the graph show significant decrease in performance. (Lower left graph)
Ha… So true.
And the BMS will enforce that recommended, half capacity, 37A per battery.
But @ALF-Li, as an exercise, if you are curious, you can log onto battery on the console port and read from the BMS the values for charging/discharging over current alarms and their recovery values. Usually they are 0.9C.
The battery will allow abuse (in other words continuously discharging higher than recommended). But long term is is not good for the health and longevity of the battery. (Source of information a callout I had with an 8kVa and 2x3000 pylons at 2 years old. FYI waaaay too small)
Count the 37A as the max nominal and size the bank accordingly.
I am very grateful for your reply. Thank you.
I am not a master at interpreting what is shown on the graphs. But I understood you that it is better to use a charge (discharge) current that is equal to the recommended value, or close to this value. That is, 37 A is 0.5C.
Please tell me, if I have TWO BATTERIES, which, of course, are connected in parallel, then how to interpret this recommended charge (discharge) current value of 37A? Leave 37 Amps, or what? Please tell me your opinion - please.
Sorry for the machine translation. Thank you.
If you have just one type of battery, US3000C, and if for one battery is 37A, then for 2 batteries is 37x2=74A, for 3 is 37x3 =111A, and so on…
If you want to learn, take a look here: Kirchhoff’s circuit laws
I don’t really understand.
That is, if Cerbo GX (vrm program) shows that the charging current is, for example, 60 Amps, or, for example, more, then the BMS will apply the limitation? How will we find out (and see) the real charge current?..
Thank you very much for the tip. I’ll definitely take a closer look. Your recommendations.
Now I understand one thing (actually I thought so): that if I have two IDENTICAL batteries, then the value of the RECOMMENDED charge (discharge) current is also 0.5 C (after all, the capacity of two batteries is 150 A / h) and then it is equal to 37 * 2=74 Amps. And 74 Amperes will be EXACTLY the RECOMMENDED value of charge (discharge) current.
Thanks for the answer.
I’m a little confused, probably because of the language barrier.
So if I have two identical batteries, am I correct in calculating 74A as the maximum nominal size?
Also remember, with more than one module in parallel, the current will be divided accross the modules.
Example: I have a stack of 10xUS3000C - the BMS reports 10x37A = 370A as allowed charge/discharge current to the cerbo - the live system in VRM reports a charge with a current rating of 60A, then each module will “see” a current of 60/10A = 6A applied to it.
