Due to the recent, and ongoing increases in energy costs, I wanted to see if I could make more efficient use of my 4kw roof mounted solar system…
As a result,I have recently purchased and installed a Sofar ME3000SP AC coupled inverter charger, along with 4 Rolls 85 amp lead acid batteries. The Sofar was second hand but in good condition, the batteries were new.
I had no problems connecting the Sofar up as per instructions. The batteries were connected in series, to give the required 48 volts, using 25mm cable along with a fuse and isolating switch.
2 CT were clipped to the AC solar connections and the incoming mains supply.
I followed the instructions for switching on. Switch everything, including solar off. Switch batteries on and wait 3 minutes. Then switch on the mains to the Sofar and it should come to life, after a countdown of about 180 seconds. Then reconnected the solar system to the Sofar. Then input the setting for country battery etc. YOU MUST DO THIS OR IT WILL NOT WORK CORRECTLY.
The unit then displayed a fault condition, in that the the batteries were overheating. I realised that I did not have the battery temperature sensor fitted, as one was not supplied with the unit I contacted the supplier, who were good enough to send me one. I am informed that a 100k resistor across the terminals, will get the unit started and show 25 c until the sensor can be obtained.
The sensor was later fitted, and the unit stared up in “standby” but would not operate as normal. I found that if I turned off the “Logic Interface Mode”, (on by default) everything stared to work fine.
The battery default setting were not correct for my batteries, so I entered suitable ones (available if required) and it worked well. Beware, even if you just want to look at the battery settings, the units resets them to default, and you have to re-enter all 12 of them again.
The Sofar has been working for a week now, and I would like to make the following points.
You will see above the problems I had with one of Robins diverts, I had on the system, and how that was rectified. Thank you.
When the batteries are nearly full, say 80%, the charge rate falls very low, only a few amps until fully charged. This is to be expected I suppose, but it does cause a lot of electricity to be exported rather than being saved. Fortunately Robins diverter is now picking this up and sending it to the water.
On setup the unit was continually exporting over 100 watts. But going to “CT calibration”, by trial
l and error this could be reduced to about 5 watts. This does not sound much, but it is enough to trigger Robins diverter.
On startup, the unit automatically sets the CTs as required, but resets them on every other startup. If you have the unit running well, you can go to “Freeze CT” and they will remain as you have set them.
The Sofar does come with Wi-Fi monitoring, using the Solarman app. However this does not work well. It is very difficult connect to the server, and it only works when it feels like it. I can find no way to update the readings, and many hours may pass between updates. If anyone knows anything better please let me know.
Sorry for the length of this post, but I thought my experiences may save someone a lot of work.
I would be happy to answer any questions, if I can.