Here are my notes on upgrading the firmware. Thanks to Tim who posted in the comments on this page: https://www.setfirelabs.com/building-automation/sofar-solar-me3000sp-battery-inverters and confirmed that with the new formware, the Depth of Discharge can now go to 90% with the Pylontech batteries.

I had never previously changed the firmware which was 2.40 but have now been through the process on my inverters and documented it here to I can refer to it next time.

Step 0 – Did you freeze your CTs?

The firmware upgrade requires that you power down your inverter. You should ensure you have your CT settings frozen first – see this page for instructions (setting up CTs section).

Step 1 – Power down the inverter

Turn off the AC power to the inverter, pull the fused DC isolator if you have one or turn off your complete battery pile.

Step 2 – Remove communications cover

Remove the waterproof cover to the communications cables (loosen the glands first).

Step 3 – Remove the microSD card

Inside the cover is the microSD card slot, which should have a card already in it. Press the card edge until it clicks. Release and it will then drop out of its slot enough so you can grab hold of it and withdraw it. The card is formatted MSDOS FAT32 and my card has CSV files on it with daily/monthly logging.

Step 4 – Set up a new SD Card with the new firmware

Tim suggested in the comments that upgrading to 3.00+ firmware should be performed in 2 steps – first upgrade to 3.00 and then beyond. I thought I would give it a go straight to 3.06.. which worked fine.

To do this, you need to download the firmware from here and prepare the micro SD card. Unzip the appropriate firmware so you have an ES3000firmware folder with .bin files in it.

The microSD card needs to be formatted as MSDOS FAT32. Sofar instructions tell you to format the existing card, but I used another card which already came formatted that way. I used an adapter to plug it into my Macbook.

I copied the ES3000firmware folder to it and then inserted it into the card slot on the inverter (still powered down).

Next power the inverter back up. DC first, then wait 5 seconds then AC. It should boot as normal and then begin operation as if nothing had happened.

Step 5 – The actual upgrade

Use the back button to get the menu up, then select 4. Software Update.

Press enter, then put in the password 0715.

Here is the successful update sequence. Once the password has been correctly entered, you don’t need to do anything else.

You can confirm the update worked:

Step 6 – Did it fail?

My success rate first time round was 1 out of 3. All my failures were on DPS2:

The update continues after DSP2 fails and the inverter reboots. However, the battery communications don’t work so this is not a satisfactory state to leave the inverter in.

If this happens, return to the start of Step 5 and try again.

Step 7 – Power down / replace card / restart

At this point, the inverter had started up and was operating normally. I then powered it down again, then swapped the microSD card for the original one. If you put the firmware on the original card, you wouldn’t need to do this. The Sofar instructions do say to power it down and restart though.

Successful update – new features

Moving from 2.40 to 3.06 gave me two new features – a new battery parameter with the ability to select US3000 batteries:

Plus depth of discharge now up to 90%: