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Growatt Inverters throttle battery charging

Peterson

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Jul 13, 2022
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Hello, I have 5 Growatt SPF 5000es working in three phase system. I have 5 Rosen Powerwall 48v 150ah. Everything is working well including the BMS communication with the batteries. Each battery has a charging ampere capacity of 150ah but unfortunately, the growatt inverters are throttling the charging capacity ampere. It only charges the batteries at 20A per inverter that makes a total of 100A but when I change the program 05 to "US2" instead of "LI", the charging goes up to a 100A per inverter. Any ideas on this problem?
 
Maybe the BMS are limiting the charge current for some reason. Perhaps they are imbalanced. Have you checked the cell voltages?

When in LI mode, do the MPPT share the programmed total, or is it per inverter?

How is it that you are using 5 inverters in a 3 phase system?
 
Maybe the BMS are limiting the charge current for some reason. Perhaps they are imbalanced. Have you checked the cell voltages?

When in LI mode, do the MPPT share the programmed total, or is it per inverter?

How is it that you are using 5 inverters in a 3 phase system?
Yes, I tried disconnecting 1 inverter in this system and the charging current raised from 20A to 25A.

I’m not so sure on this but I think they would share. Considering that 1 battery is rated for 150A and all 5 are connected in a combiner box and BMS communication in series, that should make it a total of 750A. Growatt SPF 5000es charging capacity is 100A per inverter. That should give me a total of 500A charging capacity

This is my setup:
2 5000es Inverters in Parallel for Line 1
2 5000es Inverters in Parallel for Line 2
1 5000es Inverter for Line 3
 
This is my setup
 

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I wasn't aware you could run imbalanced legs.
Unfortunately, this sounds like a limitation with the configuration. Have you contacted your vendor?
Yes, you could set it up however you prefer it. You could have all 4 inverters in Line 1 and 1 inverter each of Line’s 2 and 3. We are limited to just 6 inverters in total though.

Yes, they are still looking into this throttling problem.
 
Well, it seems you’ve established via turning off one inverter and seeing the others increase charge current, that the limitation is being set by the BMS, not the inverters.

I’m curious what you hear back, but my brain has already started to ask the followup question of: what is the downside of taking the batteries out of parallel and hooking one to each inverter? The thing that comes to mind immediately for me is that my 2 5000es in parallel don’t precisely share load 50/50 between them. Your pack voltages would diverge. I guess if i got the bad news that i was ‘stuck’ with 5 expensive batteries that wouldnt let me recharge at a reasonable rate when paralleled, i would resort to creating some kind of external ‘pack balancing’ apparatus. But i’m guessing this problem is probably fixable in software on the bms side.
 
Well, it seems you’ve established via turning off one inverter and seeing the others increase charge current, that the limitation is being set by the BMS, not the inverters.

I’m curious what you hear back, but my brain has already started to ask the followup question of: what is the downside of taking the batteries out of parallel and hooking one to each inverter? The thing that comes to mind immediately for me is that my 2 5000es in parallel don’t precisely share load 50/50 between them. Your pack voltages would diverge. I guess if i got the bad news that i was ‘stuck’ with 5 expensive batteries that wouldnt let me recharge at a reasonable rate when paralleled, i would resort to creating some kind of external ‘pack balancing’ apparatus. But i’m guessing this problem is probably fixable in software on the bms side.
Hi Vigo

Yes, this is most likely. I asked for the datasheet of the battery from Rosen and it is supposedly rated as 150A charge current.

In my situation for Three phase system. The loads are definitely not balanced so instead of 1 big battery bank for the entire system, you get 1 battery with 150ah capacity per Phase or Line. So if the loads in the system favor more on the other lines, they would run out of battery power ahead of the phase with smaller loads. Yes, I’ve been communicating with Rosen regarding the software updates on the BMS or the inverter itself
 
The specification for the 200A 48v Rosen powerwall indicates that the standard charge is 20A (Page 3, line 7). The maximum charge current is 100A (line 9, same page). It's a 15s4p pack, so I'm guessing yours is a 15s3p pack with the same BMS, given that you are seeing the same two limits applied.

hi stienman!

I asked for a datasheet from Rosen and this is what they gave me.
 

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Based on that spec sheet I would be very annoyed if the BMS throttled charging down to essentially 20a per battery, but i also understand that nothing on that sheet describes bms behavior when paralleled. Was that desbribed anywhere on their website or other documents?
 
Based on that spec sheet I would be very annoyed if the BMS throttled charging down to essentially 20a per battery, but i also understand that nothing on that sheet describes bms behavior when paralleled. Was that desbribed anywhere on their website or other documents?
You have a good point, I’ll raise this up with Rosen. I did not find any documents with the behavior of the BMS when connected to other batteries. I directly assumed that the capacity increases when it is in parallel connection to the others.
 
Have the same throttling problem with Growatt 5000es and lifepower4 battery bank. If I disconnect the inverter from the battery bank (don’t use inverter BMS) they charge at full tilt. If I connect the inverter BMs to manage the batteries, charging goes down to less than 1/3.
 
Did you flip the dip switches to give all the batteries different addresses? What if you disconnect the RS485 communication between the inverters and the batteries? Then will they charge at higher rates?

EDIT: Just realized this is an old thread, but I'd like to hear how things turned out in the end.
 
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