Growatt: not charging after full

[chrisstratton]

I have noticed that when I connect to shore power to grow out 3000 will fully charge to 100% on the 24 V lithium batteries. However, from that point the charging it seems to drop fairly low unless I disconnect the battery and reconnect it. I’ve seen some discussion about the floating voltage and the bulk charge or something similar. I’ve tried do use Will‘s recipe for Settings. Is there some rule of thumb for where to sit the floating and both charge points??

 

[Rednecktek]

I have noticed that when I connect to shore power to grow out 3000 will fully charge to 100% on the 24 V lithium batteries. However, from that point the charging it seems to drop fairly low unless I disconnect the battery and reconnect it. I’ve seen some discussion about the floating voltage and the bulk charge or something similar. I’ve tried do use Will‘s recipe for Settings. Is there some rule of thumb for where to sit the floating and both charge points??

IIRC the Growatts don't deal with all the different voltage stuff when they're working from utility power, it's just a "Start Charging at %N Volts, Stop Charging at %N volts" settings. When it's getting power from the solar is when all the bulk/float/etc settings come into play.

As I understand (very little) LFP batteries, the same voltage can be 50% charged, 70% charged, 98% charged and the controllers that rely on battery voltage to determine SOC (like lead acids do) can't tell the difference much and never read right anyways.

 

[chrisstratton]

IIRC the Growatts don't deal with all the different voltage stuff when they're working from utility power, it's just a "Start Charging

Thank you! So as far as we know, there’s no way to change the way it charges when on shore power? Or perhaps there might be settings somewhere else? To measure the state of charge I’m using the Bluetooth off the bms.

 

[Rednecktek]

Thank you! So as far as we know, there’s no way to change the way it charges when on shore power? Or perhaps there might be settings somewhere else? To measure the state of charge I’m using the Bluetooth off the bms.

As I understand the manual on mine, you can change the voltages for starting and stopping the charging (each is a different setting) voltages, but that's it.

 

[chrisstratton]

As I understand the manual on mine, you can change the voltages for starting and stopping the charging (each is a different setting) voltages, but that's it.

I got a response from 247 - basically, set the parameter for number 13 as high as possible, then the setting for number 12 of the Growatt 3000 lower than that for 13. However, this seems to only hold the charge between 45 and 75%, after initially charging to 100%.