Sofar Solar ME3000SP Battery Inverters – installation tips

Sofar ME3000SP Inverter

Some useful things about this inverter which are not mentioned, or not obvious from the manual. This is based on experience with software version 2.4.

Connecting things up

You will need a replacement 20mm cable gland for the mains connection(s) if you are using a 3-core flex as the bung in each cable gland has 3x small holes and so expects 3x single core cables.

Mains cable gland

The unit comes with 2x M6 cable lugs for 25sqmm DC cables but M8 lugs fit fine (eg. on the end of the Pylontech cables).

Setting up the CTs

The unit comes with 2x CT clamps:

CT clamp

One is for the supply and should be clipped on to your incoming supply live (big fat single-core cable next to your meter). The other is to monitor your generation and so clips to the live wire supply to your PV panels (inside your generation board etc.).

The setup procedure for your inverter includes the steps:

  1. Make sure all PV is off.
  2. Turn on battery supply to inverter.
  3. Turn on mains supply to inverter.
  4. (now set up time/grid profile/battery)
  5. Make sure you are consuming at least 200W.
  6. Turn on the PV and watch it on the display.

What has actually happened here is that the system has worked out which way round the current clamps are (remember you didn’t have to install them a particular way round?)

Now the important part: if you switch off and restart the system, it will go through the same CT configuration again. In fact, there appear to be a number of ‘events’ which cause the CT reconfig:

  • Mains off/on
  • Battery off/on
  • Change work mode

That means that if you cause the CT reconfig when you are exporting power, it will incorrectly read this as an import and then start exporting until it reaches maximum export. Imagine you are currently exporting 2.5kW from your PV – this then ramps up to 2.5kW plus another 3kW from the inverter = 5.5kW export! You do have a G99 relay to stop this don’t you?!?

There is a way round this though: FREEZE CT. This is something you should do when you are happy it is configured correctly. Go to Configuration, then down to option 13:

13 - CT configuration

Enter the password:

Enter password

You will see the CTs, and at the bottom ‘UNFREEZE’ (which counter-intuitively means ‘CTs not frozen’:

CT Unfreeze

Press the down button to display ‘FREEZE’:

CT Freeze

..and then press ‘enter’ to save (then enter again to get off the confirmation screen). You can check the CT direction is frozen from System Information, screen 4:

System Information

..which should now show ‘Frozen’:

System Information 4

CTpv isn’t needed

It is possible to use this inverter without the pv sensor. It appears the CTa clamp is the only one used for import/export. This is good news for people who are not able to monitor all (or any) of their generation due to it being connected into different parts of the mains system without a central point for a CT. Obviously you won’t get logged data for the generation and various totals will not be accurate on the system.

Datalogger

The inverter comes with a datalogger with WiFi. This is something not mentioned in the manual for the inverter. It connects to a DB9 port on the bottom of the unit and once you have it connected to your wifi network, it posts the unit’s data to the Solarman cloud-based system.

Datalogger

Pylontech US3000 and battery capacity

The inverter doesn’t seem to be able to tell the difference between the US2000 and US3000 on the CAN bus at the moment and so incorrectly sets the capacity to 50Ah per battery instead of 75Ah for the larger US3000.

Changing battery settings

Beware: In order to change battery settings, you have to start by selecting the battery type – at this point, the defaults are loaded, overwriting whatever tweaks you previously made. Make sure you go through each parameter again!

18 thoughts on “Sofar Solar ME3000SP Battery Inverters – installation tips

  1. Vasile

    Hello! Could you please let me know how I can totally block export to grid from ME3000SP? I do not want any current from my batteries to be exported to grid, no matter how. From the inverter it was easy to accomplish that, by setting reflux to 0kw, but from ME3000SP I have no idea. Thank you!

    Reply
    1. Jonathan Clark Post author

      The default work mode is ‘Auto’ which will stop any export to the grid. Of course, if you are generating more power than your inverter can send to the batteries, it will export what it can’t use.

      Reply
      1. Joseph

        Thanks for the tip about freezing the CT settings, very helpful.

        I’ve found that there is always a small export to the grid when in auto mode, around 40 to 50 watts. Not enough to worry about normally, but it is enough to cause our PV immersion heater diverter to sense an export and then use battery power, rather than solar power, to heat our hot water. It senses import/export using a CT on the tails, adjacent to the one for the ME3000SP.

        I’ve been looking through the settings to see if there’s any way to block this small export, but haven’t yet seen an obvious way to do it. Ideally I’d prefer it if there was just a tiny import when it’s running in auto mode, just so the PV hot water diverter can do its thing properly. The work around at the moment is to physically turn off the PV diverter and just use off peak for heating the hot water, but come next spring, when we get more PV generation, it would be good to have this work automatically.

        Any tips or ideas anyone has would be welcome, as would links to any sites where people have had a similar issue.

        Reply
        1. Jonathan Clark Post author

          Often there is export as the inverter ramps up it’s charging. This happens particularly on a sunny day when clouds pass, or the switching of a load such as a pump motor which, for example, goes from 1kW to zero in a fraction of a second. Getting your diverter set up correctly is important here.

          I have MyEnergi Eddis on each phase which have Advanced >> Supply Grid settings as Export margin = 250W, Export Threshold = 50W and Response Delay = 3s. This seems to avoid the hot water tank drawing power from the batteries. Perhaps your system has similar settings?

          Reply
          1. Joseph

            Thanks, in case it helps anyone else, I’ve found a fix for this. The problem seems to be caused by the way the ME3000SP reads the CT. There is a setting (menu option 16 in the firmware in my unit) that is labelled “CT Calibration”. This is really a misnomer, as this function adjusts the CT offset around zero watts measured (really amps, in terms of the measured value).

            It’s possible to enter the password (the low level user password 0001 is fine) and then adjust the zero offset up and down in increments of 1 watt. I adjusted mine up so that the actual power measured at the incoming supply was close to zero, with the ME3000SP running in auto mode.

            This has completely cured the problem, as the ME3000SP is now correctly seeing imports and exports. Before the small offset internally was causing it to incorrectly sense the zero power point.

            As a tip for anyone doing this, it does seem to be a bit of an iterative process, and you may need to do as I did and log power for a time, make and adjustment to the CT offset, log for a bit longer, make another adjustment, until you get it spot on. Part of the reason for having to adjust it like this is because every adjustment changes the input/output of the inverter/charger slightly.

            Hope this helps.

    1. Jonathan Clark Post author

      Hi Mark,

      Yes – the wire can be extended. The manual specifies a particular size of cable, but this is rubbish really since the device is reporting current – any losses from a thin cable are not important since the current is the same. I have successfully extended with 50+ metres of cat6 cable, using a single twisted pair for each clamp.

      Reply
  2. Bruce Durant

    Hi, Can you change the channels that the Sofar Wifi Works on? I cant find anything specific in the set up and It is sitting on Channel 1 and trying to act as an access point/relay for everything in the house. Its a big house with three other WIFI transmitters wired to the router to get the coverage. It seams to be causing all sorts of contention issues that go away if the Sofar is turned off.

    Reply
    1. Jonathan Clark Post author

      It’s a while since I set them up, but it should only be acting as an access point until the setup is complete. If you are not using Solarman for reporting, you can safely unplug the Wifi dongle from the serial port (and refit the cover plate).

      I just checked mine and none is acting as an access point.

      Reply
  3. Bob Hughes

    I am looking at installing Pylontech US3000C batteries starting with one unit but the Dip switch setting seems a bit confusing some saying its the opposite way round to the manual.
    Have you got a pic of what it should be for 1 battery (it obviously will be master) ??
    Currently I have a ME3000SP working with 2 Amass GTX2000 but one battery developed a fault so thought I would move on to Pylontech, will the Can bus cable supplied with the ME3000SP still work with the Pylontech batteries or is the Pylontech wired differently??
    Many thanks

    Reply
    1. Jonathan Clark Post author

      The supplied cable (RJ11 marked INVERTER to RJ45 marked BAT) will connect fine to the ME3000SP. The battery type should then be set to PYLON, and then check/adjust the battery capacity which I think will be incorrect.

      DIP switches are for RS485 baud rate (which you are not using with ME3000SP) and CAN termination which should be left as terminated. All my US3000 and US3000Cs came with DIP switches all set to OFF. However, on the 3000C the DIP switch block has been mounted upside-down which might explain the confusion.

      Reply
  4. Bob Hughes

    Yes the RJ11 – RJ45 works fine and on the ME3000SP V2.8 firmware the battery option does have Pylon and a US3000 option but no US3000C yet.
    The latest version is now V3.0 so maybe that will have the US3000C option in it allowing the deeper DOD of the US3000C as the max in V2.8 is 85%.
    Thanks for your info

    Reply
  5. Dick Middleton

    Interesting. Quite Chinese! I’ve not got my equipment yet so I’m worrying about more mundane stuff: the manual recommends a 100A DC isolator, I assume 2-pole, between battery and inverter – did you bother? Quite an expensive item and not easy to source. Did you put in a 25A AC circuit (mains) as recommended? I would think 16A into consumer unit would be perfectly OK. Maybe 25A is a standard US rating.

    Reply
  6. Simon

    Hi. I have just switched over to Octopus Go so set up my ME3000SP to charge at cheap rate my Pylon batteries (Master 1x US3000c + 2x US2000). I’ve set it up on Time-of-use Mode, a couple of questions that you may be able to help with..
    The display requires two dates, start and end, if I set the start date as today what date should I use for the end setting so that the system runs continuously? At the moment I’ve set the end date as one day prior to the start date.
    Does the Inverter automatically adjust the time when the clocks change or will I have to update the time myself?
    I’ve noticed that having set up the time of use mode when I now check the energy statistics it shows the total load for the day as eg. 3kw but the self use is 0% and the import is 100%.
    I’ve emailed Sofar but they haven’t come back with anything yet!

    TIA for any help you can offer

    Reply
    1. Jonathan Clark Post author

      Hi Simon,

      I think you are correct in with the dates.

      I have Time-of-use mode set and I ignored the dates (which have the end date before the start by default). Since we have now passed the clocks change, I can confirm that the time changed automatically – which I expect you also already know!. I think the times are set using the serial dongle.

      Reply
  7. Alex

    Any way to buy the right CT clamps? I Need 2 more.
    Anybody have the same Problem??
    LCD is blinking and don’ t reakting on Buttons.
    Half day blinking the other half day working well.
    Sorry 4 my realy bad Englisch.
    Thx

    Reply
    1. Jonathan Clark Post author

      LCD blinking sounds like a fault. Speak to your supplier. If it is the charge and discharge LEDs then this is ok – it indicates a standby state.

      The Current transformers (CT) are I think 1000:1 so 100A becomes a 100mA output. I think this is a standard for this type of thing – Open Energy Monitor, SMA, Sofar Solar all use this standard. It is possible to find them on eBay: Current Transformer
      If the CT is for the PV monitoring, it is also possible to calibrate it in the settings.

      Reply

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