question

cristobalfleischmann avatar image
cristobalfleischmann asked

mppt 250/60 does not recive the voltage from the panels

hello, the mppt 250/60 does not receive nothing from the panels. i disconect the pv and battery a coulples of times and nothing happen. is like the entrance o the PV die, y use the tester i put in the screws of the PV and show me 0,0 V , but when i put the tester on the PV cables showme the voltage of the 8 panels 131 V. plese help.

MPPT Controllers
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5 Answers
marin avatar image
marin answered ·

If the PV voltage reads 0 after connecting the PV to the solar charger, the polarity of the PV is probably reversed.

The MPPT is protected for reverse polarity, (if i understand correctly, the current is routed over a diode). This means the panels will be in short circuit current condition (Vpv ~0 V)

Try reversing the polarity + and - of the PV cables on de MPPT.

Manual states that the MPPT should become slightly warm when the PV polarity is reversed..

1 comment
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cristobalfleischmann avatar image cristobalfleischmann commented ·

i think the same but is not the problem, i check all ready the polarity and is ok. i do the test reversing the polarity and nothing happen.

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sonnenflo avatar image
sonnenflo answered ·

Hello,

I have also a Victron MPPT 250/60 Tracker and it worked very well since more than one year. Yesterday I disconnected the input plus and minus because I re-router the cable and after connection I measured 0,03V on the PV input screws. Did you get a solution for this problem? thank you. Florian

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gazza avatar image
gazza answered ·

I know you have already tried this but.... Disconnect PV first, then disconnect battery to the MPPT.
WAIT... a few minutes.
Re-connect battery terminals first... check voltage at battery terminals. Then, re-check PV voltage open circuit, if correct polarity connect to MPPT.
If that still does not work then there could be a hard fault. Have you experienced any possible high voltage on the PV cables, lightning?

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sonnenflo avatar image
sonnenflo answered ·

Hello,

So I already tried that with the disconnect, unfortunately that did not help. A high voltage, by lightning or otherwise, I have not had, I have only disconnected the PV input and reconnected. If I disconnect the input, I have 130 volts on the cable, if I connect the cable, I have 0.03 volts on the input screws of the controller. Yesterday I tried another PV panel, which I have in stock as a reserve, and there it works fine again. A polarity reversal has not taken place.

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gazza avatar image gazza commented ·
Ahh so it is not the MPPT ... if another PV panel works fine? Did you use the exact same cable/MC4 connectors to conduct that test.. or a different set of cables?
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sonnenflo avatar image sonnenflo gazza commented ·

So I have 3 panels connected in series, each one terminated and measured through -> there I also get voltage from every single panel, just every single panel doesn't work with the old cable I used until now either. I connected the spare panel with another cable for testing, the tracker works there. I also think that the tracker is not the problem. Now I have connected the 3 panels with the other (new) cable, and the tracker also has no input voltage. So it is very strange.

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gazza avatar image gazza commented ·

Our messages crossed. I would certainly look at all cable connections/terminations, possibly cleaning with suitable electrical contact cleaner. Failing that there could be a faulty diode somewhere in your array. It may be possible to find which panel by elimination

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sonnenflo avatar image
sonnenflo answered ·

I have found the solution to my problem. As already stated above in the problem description, I had a voltage of 130 at the cable, I clamped both wires to the Victron charge controller, I then only got a voltage of 0.03 volts. The cable I have measured through, and otherwise I have also checked everything and as also already written, it worked with a temporary cable. So since I really tested everything, I tried the last option, which I have not yet tried: I cut both MC4 connectors from the original cable, which were plugged into the MC4 connectors of the PV modules, and lo and behold, the charge controller was able to do something again. The MC4 connector was the reason, in the plugged state has not worked properly.

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