Hi everyone,
I'm hoping someone can help me troubleshoot a frustrating charging issue with my Growatt SPF 6000 ES, or point me toward a firmware update that might fix it.
My Setup:
- Growatt SPF 6000 ES (Serial: NMR1NXJ07K)
- Firmware: 100.06 (Main) / 101.05 (Secondary)
- Batteries: 2× ATG OT48100 (51.2V 100Ah LiFePO4) in parallel
- Use case: Solar + Grid hybrid powering an air conditioner
- Monitoring via Solar Assistant
- Note: Running in User2 Mode - I haven't been able to get the battery BMS to communicate with the inverter
The Problem:
Whenever my solar panels are connected, the inverter drastically throttles grid charging to only about 7.6A, even though I have it configured for 50A max grid charge and 90A total charge current. This happens regardless of which "Charger Source Priority" setting I use.
What I've Tested:
Solar disconnected (grid only):
- Battery charges at 50A as expected
- Grid delivers 2,740W to batteries
- Everything works normally
Solar connected (any simultaneous mode):
- Battery charging drops to only 7.6A from grid
- Grid contribution: 75W
- Solar adds: 336W
- Total charging way below the 90A limit
I've tried both "Solar and utility simultaneously" and "Utility first" modes - same throttling in both cases. Battery is at 54.1V, well below my absorption voltage of 56.8V, so there's plenty of room to charge.
Current Settings:
- Battery absorption: 56.8V
- Float voltage: 54.4V
- Max charge current: 90A
- Max grid charge: 50A
- Battery type: User2 (since BMS communication isn't working)
My Questions:
- Has anyone else experienced this behavior with the SPF 6000 series?
- Could running in User2 mode without BMS communication be causing this throttling issue?
- Is there a newer firmware version that fixes simultaneous charging?
- Are there any configuration tweaks that might help?
- Has anyone successfully gotten the ATG OT48100 BMS to communicate with the SPF 6000?
Right now I'm having to physically disconnect the solar panels when I need grid charging, which obviously isn't sustainable.
Any advice or shared experiences would be greatly appreciated!
Thanks in advance.
