Hi!

I have a Growatt SPF5000ES inverter. It was working nicely with a set of 2x US2000C batteries. BMS connected with the inverter and monitoring using SolarAssistant.
Each battery apparently recommend 25A when charging/discharging and for the rack of 2, SolarAssistant shows 50A. As max I saw charging values of 35-40A (I don't have too many solar panels). That's right I guess.

But, yesterday I added a new US3000C to the rack. Mixing them was quite fast, given they are compatible and the inverter also detected the US3000C as master with the same config. Btw, now SolarAssistant is showing that the recommended charging/discharging value is 37.0A (the one for US3000C), so... now the whole bank is not gonna be recharged with higher intensity I guess? If so, why? Why are they not sum with the 2x US2000C?

In my honest opinion it should be 50 + 37 -> 87A as max, but somehow is 37A... Any idea why?

Thank you!

Edited October 26, 20223 yr by Dæv

Hi have 3 Us3000c batteries and Solar assistant says recommended charge/discharge 37amp but if I look in the inverter settings it is changing as the state of charge changes. When Low COC it is normally 110Amps and will decrease when above 90%.

11 minutes ago, Jacques Ester said:

Hi have 3 Us3000c batteries and Solar assistant says recommended charge/discharge 37amp but if I look in the inverter settings it is changing as the state of charge changes. When Low COC it is normally 110Amps and will decrease when above 90%.

Oh! Interesting point! Will check the inverter settings now! Thank you

When it comes to batteries, adding another in parallel is a little more complex than just adding the currents. Depending on how the batteries are wired and whether there is a connection box between the batteries, your charging currents are going to be a little odd.

I am no PylonTech or Growatt expert, mostly work with other brands, but the theory should remain the same. The inverter should be doing a careful balancing act depending on the SOC of the battery and the power it's getting from solar. Things like source/charge priority also play a part in how charging currents are set by the inverter. 

My only real input here would be make sure the batteries and inverter are all communicating with one another. Usually I advise users avoid mixing different Ah batteries because it becomes a nightmare for safe charging, the BMS will definitely help though with a lot of it.

6 hours ago, Psy said:

When it comes to batteries, adding another in parallel is a little more complex than just adding the currents. Depending on how the batteries are wired and whether there is a connection box between the batteries, your charging currents are going to be a little odd.

I am no PylonTech or Growatt expert, mostly work with other brands, but the theory should remain the same. The inverter should be doing a careful balancing act depending on the SOC of the battery and the power it's getting from solar. Things like source/charge priority also play a part in how charging currents are set by the inverter. 

My only real input here would be make sure the batteries and inverter are all communicating with one another. Usually I advise users avoid mixing different Ah batteries because it becomes a nightmare for safe charging, the BMS will definitely help though with a lot of it.

Thank you for that. Yes, they're all communicating with one another and the "master" is well communicated with the inverter, so I'm not worried about safe charging due this.

Maybe the max Ah is set to 37A given I have mixed different Ah batteries and they take this value for safety reasons (the BMS rules here hahahh).


----

Btw, I just wrote an email to Pylontech support ('sales' email but I cannot find other). I hope they can bring some light on this topic.

Edited October 26, 20223 yr by Dæv

Something not right, BMS is not taking your 2 US2000s into account (maybe not communicating properly with them)...

I had identical setup, 1 US3000 and 2 US2000s. BMS showed max charge/discharge as 87A (37+25+25).

Did you update the battery firmwares before connecting up?

 

1 hour ago, markus_m2 said:

Something not right, BMS is not taking your 2 US2000s into account (maybe not communicating properly with them)...

I had identical setup, 1 US3000 and 2 US2000s. BMS showed max charge/discharge as 87A (37+25+25).

Did you update the battery firmwares before connecting up?

 

Oh, really? 😱 No, I didn't update any firmware of my batteries.

Then I don't know what's not right 😕
 

Just check if your charging current is changing on inverter.

If it does then it is working correctly.

As you can see it shows recommended discharge/charge as 37A but on inverter it is 110Amp.

3 hours ago, Jacques Ester said:

Just check if your charging current is changing on inverter.

If it does then it is working correctly.

As you can see it shows recommended discharge/charge as 37A but on inverter it is 110Amp.

😱 Thank you so much!! That's it! Maybe is a bug from SolarAssistant or the battery is not giving by console the right data.
I guess we can close the thread here. Thank you all! :DDD

(Btw, don't get mad about the 100.0V or 10.0v values in the screenshot from below -> Growatt is internally handling percentages as voltage and SolarAssistant is showing it as voltage too, but it's not)