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Thank you for the great forum, Safe Driving over the weekend. Sincerely Jason
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PV charging problem

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Good morning all

A friend of mine is having a problem or setting that I am trying to figure out why this is happening to his solar system. He has an Axpert 5kw 48V Mecer inverter with one 3.4 Kw Pylontech Li-Ion battery and 12 x 300W PV panels connected 3 in series and then in 4 strings in parallel. Also he has the Raspberry PI installed form Centurion Solar to help with the communication between the inverter and the battery. At first he experienced that when he ran his generator (5Kw diesel generator) that it changed the settings on the inverter from SBU to UTI which was very strange as I know this is not suppose to happen. Another strange behavior is that it looks like the inverter stops to charge the battery or it switched the PV bank off even though  it indicates there is 105V coming from the PV bank but no Amps. I took a loan Axpert 5KW 48V inverter ( the same as what he had in) from my company (with approval of cause) and replaced his one and it was already performing better. We tested it with the generator and it was working 100% without any of the setting been changed and charging the battery. Now the problem that we have is that we getting a nice charge on the battery but after about 2-3 hours the PV's stop charging the battery and on the inverter and PI you can see there is 105V but no Amps to charge or the supply power to the house. During the 2-3 hours when we get power from the panels it charges the battery full and then it supplies power to the house as it should and then the power from the PV's just go off and does not come on again till the next day. There is two ways to get the PV's to supply power again: 1st is to put the battery of and on again but that is a pain to do every 3 hours or so as he is living on a farm in Cullinan area and not at home during the day. 2nd way that I noticed is when you change a setting on the PI and send it to the inverter then the PV's kick in again and start to charge and supply power again. We have changed the settings but haven't had any luck. Maybe we have missed something or just keep on overlooking a curtain setting but I hope someone has got an idea of what is happening. I am struggling to connect to his PI to take some screen shots of the current settings and charging curves as the server is down due to the lock down.

Do I need to try and do a firmware upgrade?

Just to give a little bit info of my back ground: I work for a medical company, LTE Medical Solutions. We build mobile clinics that we supply to Africa with solar solutions to run the clinics of as a backup or last resort for power and for when the Mains supply or generator supply fails. On all our mobile clinics we running 2 x 3.4KW Li-Ion batteries from Solar MD together with 2 x Axpert 5KW 48V inverters all in parallel and depending on the size of the clinic with 6 - 14 PV's on the roof. Lately we changed to the Pylontech Li-Ion 3.4KW batteries as we found the Solar MD batteries gave alot of problems/errors due to the client that does not know how to look after then after numerous training I gave to then.

Regards

MrBigT

 

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Im also having the same issue

I have a Axpert 5kva invert form the Sun Pays with 2x Pylontech. I find that the batteries get to 91% and then the solar shuts off.

Have you guys found the issue yet? today i ran the inverter with no load and the same problem.

Screen shot.PNG

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1 hour ago, charl said:

I have a Axpert 5kva invert form the Sun Pays with 2x Pylontech. I find that the batteries get to 91% and then the solar shuts off.

My guess is that you're not connecting ICC to the battery BMS properly, so it's falling back to the inaccurate inverter SOC figure. If your low DC cutoff voltage (setting 29) is 42.0 V, that's considered 2% SOC, and every tenth of a volt above that it considered one more percent SOC. So at 50.9 V, the SOC will come to (50.9 - 42)/0.1 + 2 = 91%. The fact that it's that close to 100% is actually amazing.

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Thanks for the reply

How do I make sure ICC is communicating with the BMV properly

It does look like the inverter state of charge is higher than that from the Pylontech. If i go to the Pylontech tab, it does show it is receiving data

I do have setting 29 at 42.0V

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