MaxUmis

@JoeyhZA yeah, more or less. Once the batteries are full the unit disconnects the panels. The PV icon is still lit, but the line going to "charger" icon is out. When the PV panels kick in again, the line going to the "charger" icon lights up and the panels contribute to load and charge the batteries. @Coulomb it's not the end of the world. It just makes me twitch to know that I'm drawing saved power from batteries with a limited number of charge cycles when there is glorious sunshine beating down on my panels outside. The 3000TL is paired with 2x 12V 200A lifepo4 batteries. They sit in a cart with wheels so I can move the system around. The cart is fitted with a couple of 220V outlets, an inlet (for charging via generator) and some 12V and USB outlets. PV comes from 4x 370W Longi's. But I'm only testing with 2. This setup will help me build our cabin on our small farm. When the cabin is complete this system will stay there to provide power when we head up there over weekends.

So the issue that landed me in this mess was the fact that the inverter would switch off my panels once the batteries are fully charged. I thought that must be a mistake and obviously updated the firmware. (I used the wrong firmware which made the inverter unresponsive. Then got the proper firmware from Growatt which fixed the unresponsive inverter.) As mentioned by hoohloc, it turns out this is just the way these SPF XXXX TL HVM inverters operate. So I Googled and Googled to get more info about how the inverter decides when to power up the panels again. All I could find were mentions of SOL and SBU for option 1 and 95% of State of Charge. But experimenting with those settings didn't convince me that they're particularly relevant. For my first experiment this morning I waited for the PV panels to top up the batteries. Then I hooked up my laptop and screen (140W) as a "base" load. Then I added my 1.7kw heat gun and started running it for 2 or 3mins at a time. Watching the voltage drop as I go. At this point my Option 13 was set to 26.5V. After a couple of runs with the heat gun the voltage dropped below 26.5V, but would recover back to 26.8V once I turned the gun off. I even got the voltage to drop down to 26.1V while running the heat gun, but again, after switching it off the batteries recovered to 26.6V... So I got fed up playing with the heat gun and fetched our dehumidifier. I plugged in the dehumidifier with laptop load. The battery voltage dropped to 26.5V and viola! The panels powered up. For the second experiment I recognised that my Option 13 was set to 26.5V so I changed that to 26.7V and waited for the batteries to charge back up. Once full I switched the dehumidifier back on to have about 470W load and waited for the battery voltage to drop again. Low and behold, at 26.7V the PV panels started to charge the batteries. I also tried setting option 13 to 27V, but the panels came on at 26.7V. So my theory about how the SPF 3000 TL HVM 24 decides when to use PV panels is: Use Option 13 if it's less than 95% SoC (26.7V) else use 26.7V Consider Load % from some kind of lookup table. Like the one used to display battery capacity remaining. I'm a little disappointed that this behavior isn't documented somewhere official. Had I known I would have looked further than what seemed like the obvious choice for an "off grid solar inverter". I think that calling this thing an inverter is a little misleading. Maybe calling it a "multi-source battery charger with built in inverter" is more accurate.

Good news. Xing (Amos) came through with the correct firmware. I flashed the inverter and it's back up and running 🙌 I did note that this firmware is named F28035_GW503.08_[Date] and the stuff that broke the inverter started with F2809. So if you are planning to flash a SPF3000TL HVM-24 the correct firmware will likely start with F28035. And a note to "past me": Get firmware from the supplier (Growatt support)! Big thanks to @hoohloc for helping me out.

Thanks H, I'll shoot them an email. Fingers crossed. 🤞

Thanks hoohloc. It would have been nice if this behavior was noted in the manual somewhere hey. It would have saved me hours of wasted time and heartbreak. Hopefully this thread will save others from the same fate. Does the 94% refer to something in the setup or is it just some arb voltage Growatt decided will suit all? I would still like to try and flash the inverter again but with firmware confirmed for use with the SFP3000TL HVM-24. If anyone can let me know where to find it I'd be forever thankful.

Hi everyone, I have a slightly embarrassing first post. I had an issue with getting to use PV rather than battery as the inverter power source. During the first couple of hours of the day the panels would charge the batteries and supply power to the load as expected. But once the batteries are full, the inverter disconnects the panels and only sucks from the batteries. I searched around for GW firmware and flashed the 3000TL with the first thing I found... Now I have a dead inverter. Screen off, ac/inv led lit, chg and fault LEDs slow blinking. I can still connect via PV Keeper. It shows the batteries providing power and I can populate the empty settings fields. I'm hoping that if I flash the inverter with the proper firmware for the 3000TL that it might start up again. Can someone point me to where I might be able to get firmware for my inverter? Thanks