question

eric-adjah avatar image
eric-adjah asked

PV voltage measures Zero volt when connected to the MPPT but measures correct voltage(210V) when removed from MPPT

My 250/100 MPPT charge stopped working and when I measure the PV Voltage while connected to the MPPT, I read a Zero Voltage but when i disconnect the PV from the MPPT and measure the PV directly I read a voltage of 212V. I have similar MPPT on site with the same number of string and panels and they are working fine. Can any one help me with the situation. I have good grounding for the panels and the equipments though.



MPPT SmartSolar
9 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

eric-adjah avatar image eric-adjah commented ·

Please this is the second MPPT am facing this problem with. Although Victron will replace it for me, I will also like to know if this is a problem from my side so that I can correct my installation because this is very frustrating


0 Likes 0 ·
misullivan avatar image misullivan eric-adjah commented ·

What is reported by the MPPT ? Can you connect to it? Is it connected by ve.direct? Is the remote control link in position? Are the lights on on the MPPT? Is it bluetoothable (can you connect to it?)

0 Likes 0 ·
eric-adjah avatar image eric-adjah misullivan commented ·

Everything is off. I can't even connect my phone or computer to the MPPT.

0 Likes 0 ·
eric-adjah avatar image eric-adjah misullivan commented ·

I just got to another site this morning and found similar situation but this time the Bluetooth is on so I can connect. But it does not give me any error. It only say the PV isn't connected. While it it is connected. I measure the PV Voltage while connected to the MPPT but the voltage reads Zero Voltage but when i disconnect from the MPPT, I read 240V.

0 Likes 0 ·
Mark avatar image Mark ♦♦ eric-adjah commented ·

If you are reading 240V PV voltage during a random open circuit measurement, then there is a good chance that the PV voltage has exceeded the 250V PV voltage limit and you have killed the MPPT.

You need leave sufficient voltage margin to the MPPT PV voltage limit, to ensure the limit is not exceeded during conditions with perfect solar and low ambient temperature.

0 Likes 0 ·
eric-adjah avatar image eric-adjah Mark ♦♦ commented ·

But it was working for a long time and this only occurred this week. Could high voltage cause short circuit at the PV input of the MPPT controller. I checked the resistance and it was Zero at the input( between Pos and Neg)

Find attached picture when I was measuring.

0 Likes 0 ·
eric-adjah avatar image eric-adjah Mark ♦♦ commented ·

Also the controller report high voltage when it is raining. How is this also possible.

0 Likes 0 ·
misullivan avatar image misullivan eric-adjah commented ·

Did you calculate the temperature coefficient of the panels? As the temperature goes below 25C the voltage (VoC) will rise ...

0 Likes 0 ·
eric-adjah avatar image eric-adjah misullivan commented ·

I didn't calculate that. Could the high voltage cause the MPPT to get damaged causing a short circuit at the PV input of the MPPT charge Controller. Then I will have to reduce the panel by one per each string. Thanks a lot.

0 Likes 0 ·
2 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi Eric,

One cause of this is when there are panels connected in reverse polarity. That would be the first thing I would check, polarity of the individual PV strings at the MPPT.

I am not sure what you mean by good grounding. Please re-read section '3.2 - Grounding' of the product manual to make sure the system is not connected improperly to ground (e.g. "The plus and minus of the PV array should not be grounded".)

If there are no LEDs blinking and you cannot connect to the SmartSolar MPPT with VictronConnect when the PV panels are disconnected, but you are measuring battery voltage at the MPPT terminals then something has likely failed, and you should contact your dealer.

If you would like to know more about the system to make sure there isn't some error in installation or design, I would suggest completing the Victron Online Training program at http://professional.victronenergy.com/online-training/

2 comments
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

eric-adjah avatar image eric-adjah commented ·

Thank you very much for your response, 8 have removed the controller and I tested for continuity test at the PV input of the MPPT controller and the resistance was Zero. Meaning there is a short circuit at the PV Input of the MPPT charge Controller. How could this happen.

0 Likes 0 ·
eric-adjah avatar image eric-adjah commented ·

This is this picture while I was checking for the resistance between PV pos and PV neg.

0 Likes 0 ·
misullivan avatar image
misullivan answered ·

If you exceed the 250v on open circuit it will blow the MPPT and it will not display any lights and it will blow any battery fuse...


The MPPT will be dead and not covered under warranty... I had one blow the exact same symptoms (with 228vdc)... was told it was a reverse polarity or over voltage situation.. I was fortunate that it was in an easy solar .. and therefore I couldn’t have reverse polarity connected it, got a load of questions about lightning and what panels and how they were connected etc.. then they (the distributor) relented and agreed to replace it... I’ve been up ever since... I do wonder if there is something not quite right with that particular model that causes this issue though.. it’s not the first time I’ve seen it reported... and experiencing it first hand I’m concerned ... personally will be buying another 2 easysolars shortly and will be watching carefully.


In the mean time I suggest you contact your supplier about the apparent fault..


what solar configuration (panel model, how many series and parallel are there) are you and where are you located so we (the community) can calculate how close you got to VoC....?


Regards,


Michelle

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Erik,

What solar panels are you using, what is their wiring configuration and what is your location?

You can enter those details into this tool, and it will warn you if you are potentially exceeding the PV voltage input, which will destroy the MPPT. https://mppt.victronenergy.com


0 Likes 0 ·