Growatt spf5000es with JK BMS

Hermanvanveen

New Member
Hello,

- growatt spf5000es
- JK 16S 200ah BMS
- 16x 304 eve cells

I wonder if my assumptions are correct:

- bms detect a cell voltage is too low:
Growatt unit shuts down completely. Charging has to be done with an external charger

- bms detect a cell voltage is too high:
Growatt unit stays on, gives no errors, but no solar energy will be put through the bms towards the battery

Is this correct?

Thank you
 

FilterGuy

What, me worry?
Hello,

- growatt spf5000es
- JK 16S 200ah BMS
- 16x 304 eve cells

I wonder if my assumptions are correct:

- bms detect a cell voltage is too low:
Growatt unit shuts down completely. Charging has to be done with an external charger

- bms detect a cell voltage is too high:
Growatt unit stays on, gives no errors, but no solar energy will be put through the bms towards the battery

Is this correct?

Thank you

The answer is maybe.... and that is final!

It all depends on the BMS and how the system is set up.
  • Typically, the growatt will be set up to shut down discharge at a voltage that is slightly higher than the BMS would trigger a low voltage disconnect.
  • Typically, the growatt will be set up to stop charging at a voltage that is slightly lower than the BMS would trigger a low voltage disconnect.

So.... typically the BMS never does either a high voltage disconnect or a low voltage disconnect.
If something fails and the BMS does a disconnect, what happens next depends on the BMS
  • Most modern BMSs will still allow charging after a low voltage disconnect. Once the growatt charges the batteries back to a 'recovery' voltage, the BMS returns to normal operation.
  • Most modern BMSs will still allow discharge after a high voltage disconnect. Once the growatt drains the batteris back down to a 'recovery' voltage the BMS returns to normal operation.
However, Some BMSs are designed to require manual intervention to restart. The theory being that if something went wrong, then it needs to be investigated before the system is allowed to go back to normal operation.
 

Hermanvanveen

New Member
  • Most modern BMSs will still allow charging after a low voltage disconnect. Once the growatt charges the batteries back to a 'recovery' voltage, the BMS returns to normal operation.

In contrast with other systems, the growatt is an "all in one unit". Charge controller, inverter and ac charger. For it to charge the battery after the bms had a low cell disconnect, it needs to be on (and thus consumes electricity). In contrast to seperate charge controllers. So tgat made me thinking that the bms shuts down tge growatt completely (since it consumes about 50 watt), which tgen makes charging using the growatt impossible.
  • Most modern BMSs will still allow discharge after a high voltage disconnect. Once the growatt drains the batteris back down to a 'recovery' voltage the BMS returns to normal operation.

Clear, thanks
 

itechfixit

New Member
I nearly have the exact setup, I have just fitted the JK bms (Yesterday) so cant yet comment on its performace and still learning myself, but i would presume if you setup up the Growatt to control the overcharge and undercharge then the only time the jk bms would come into play other than balancing, is if it, either has a low cell reading or the growatt fails in which case you would want this. If one cell cant keep up with the others I would want it to shut down so I could investigate the problem. As, I have said im new to this so any comments would be appreciated
 
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