Growatt Inverter and "dumb" Lifepo4 Battery Solar Charge confusion

Yeah I think you are right. I have a photo somewhere comparing this Growatt side-by-side with an Axpert. The layout of the bottom panel (cable in, sockets) is almost identical. I think the Growatt only had one difference… it was Bluetooth or a CAN port or something like that. My memory fails me. Would make sense that it was Bluetooth, cause that would be really easy to add. That little comms board they have that is either RS232 or USB? Just throw one in with a BT Uart and you have bluetooth :slight_smile:

Time for a test again today (since we are load shedding and the sun is out in Jhb).

Settings are:

  • Voltage Point back to Utility (if available) = 51.2V (3.2 per cell)
  • Voltage Point back to Battery = 54.4 (3.2 per cell)
  • Bulk Charge = 56.4V (will change to 56V, balancing is happening at this point as well)
  • Float Charge = 54.6V (will see what happens if I set this to 55.2V)
  • Low DC Cutoff = 48V (highest it can be)

I can see that the solar production is currently enough to drive the entire load and also push a little charge into the battery (not that it’s needed at this point, but at least the battery is not drained like I saw earlier this week).

For reference, this is the graph for today (so far):

I can’t remember the comms it had, other than WiFi (with an add-on dongle).

Pretty sure it had an RS232. The problem we had was that the firmware was really shaky. Didn’t want to accept certain settings, or if it does it doesn’t do anything. Had no real idea what to do with lithiums because it couldn’t communicate with them. The final settings the installer put in effectively caused the battery to just be drained by the standby power draw of the inverter and never decide to charge it again (it was supposed to be in UPS mode).

At that point (this was also at the start of my solar journey, I’m sure now I understand the voltages etc. a little bit better to be able to at least get somewhat around some of those issues) I was not happy with the product and wasn’t going to put solar panels on something that doesn’t seem to know what to do with batteries. So I exchanged it for a Victron, and never looked back. :smiley:

Even now after I learned a bit more and the honeymoon phase is over, I am still super happy with my Victron. Little things I’d change if I had to redo my setup is go for 100A of MPPT capacity instead of 90A, due to my Pylontech’s 15 cells the system voltage is just not enough to put 5kW out the MPPTs, and splurge a bit on the Cerbo, for no reason other than I like the latest tech.

Anyways, I don’t need another long post in my life as to why I am so happy with Victron. :smiley: