MPPT pv short relay

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larsea-dk asked Mar 6, '24

MPPT pv short relay

MPPT, PV input shorted ?

I have two SmartSolar MPPT 250/100 one connected to 2 rows of 4x 395W and the other to 2rows of 5x395w solar panels. The system has been running fine for approx 2years, but one do not start up, blue LED blinks slowly. Voltage on PV input terminales is zero volts, but when connection is opened the solar panels show up to approx 200v in the middle of the day. On closing the switch PV terminals show zero volts. The PV input of the MPPT is in a protection mode - pv short relay.

The mppt is a HQ2211. On early models, the pv short relay reset itself. Victron did introduce a pv short relay on HQ2150, which should be able to be reset manually and the next generation HQ2250 was updated due to a design fault, because the pv short relay between model HQ2150 and HQ2250 wouldn’t reset as expected and simply needs replacing(complete unit)

https://invertersrus.com/wp-content/uploads/2022/12/Smart-Solar-MPPT-250-100-VE.Can-PV-input-protection-HQ2150.pdf

I now have the one mppt replaced but I worried that my other mppt with same design fault will break after warranty period.

Anyone having experience with these mppt’s with this design fault? Victron dealer could not find the reason for the error, so I am worried and it’s also a very expensive unit.

MPPT SmartSolar system design fault

5

2 |3000

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Alexandra ♦ commented · Mar 07 at 05:30 AM

@larsea-dk

Which one developed the fault? The one with 5 rows or 4?

I have only had one issue with the pre relay 250\100 where it could not be reset (since there was no relay).

With the relay one, depending on what firmware you were running you have to reset the error on a 12v system, so that is also a factor.

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larsea-dk Alexandra ♦ commented · Mar 07 at 07:33 AM

Hi

Yes I followed the guide I am linking to, which also mention 12v supply. but eventhough it seems like it softwarewise did reset, the pv was still shorted.

It was the one with 5 panels, but when I calculated Voc and also took temperature into the calculation, I was near 200volts and therefore with enough distance from the 250v barrier.

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larsea-dk Alexandra ♦ commented · Mar 29 at 10:22 PM

I lost contact with the VenusOS when I was not at home, so I could also not see any recording of values.

The system and therefore also the mppts are controlled by bms values, so voltage shouldn’t have been too high.

I did the reset on 12v and just followed the reset guide. It seemed like it did reset, but the relay still shorted the pv inlet.

So, as I read, Victron has found out that the mppt in a certain production series has a design error and this is why I thought that Victron would also exchange my second unit.

What happened on your system? I have thought of perhaps just testing whether my second mppt would reset by set a manual lower max voltage in the mppt setting and turn of bms controlled.

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Alexandra ♦ larsea-dk commented · Apr 16 at 04:45 PM

The relay was added to the series after the production 'issue' so the short could be reset instead of mosfet destruction. The idea is to allow some mistakes and prevent landfill. Is yours is from that series?

The real question is why did the protection activate? Were the mppts also programmed correctly? Relying on BMS only is not best practice?

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offroadflow commented · 3 days ago

About a year ago a 250/100 of a friend suddenly stopped charging. Took me a long time to get an actual replacement after really having to fight for it.

I was seen as an imbecile even from headquarters.

Made me think about the actual service from Victron. Wont forget that one ..

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