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Warwick Bruce Chapman avatar image
Warwick Bruce Chapman asked

CONCERN: VERY Hot MPPTS

I see from the 250/100 datasheet:

Operating temperature -30 to +60 °C (full rated output up to 40 °C)

In our summer conditions, almost all MPPTs we have installed are too hot to touch.

We are collecting thermal imaging to provide examples, but in some cases, we have installed forced cooling in order to satisfy customer concerns.

We are concerned that this may result in a higher failure rate than Victron intends and we note that there is no warning between Venus OS and MPPTs about temperature. We have never observed an MPPT derating on over-temperature, which we would expect to see at temperatures over 40 degrees C per the datasheet entry above.

I'm sure places like Australia and the Southern US where Victron is also popular will also be experiencing the same sort of operating temperatures.

We have designed and are testing a robust, temperature driven forced cooling solution for our installations going forward but it comes at a cost and we need to determine whether this is actually necessary from Victron's perspective.

Any input or advice on this would be appreciated.

MPPT Controllerstemperature
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mariner62 avatar image mariner62 commented ·

Warwick,

I note with interest your statement "We have never observed an MPPT derating on over-temperature, which we would expect to see at temperatures over 40 degrees C per the datasheet entry above."

I am currently trying to investigate an interesting situation we have. Two different boat-based systems, one of them shows very clear derating with temperature and the other shows no observed derating at all.

System #1 960W, Vmp:33.6V, Imp:28.9A, MPPT:150/35

System #2 720W, Vmp:43.6V, Imp:16.5A, MPPT:100/30

When operating in good sun with the controllers kept under 40 degreesC by forced cooling then System #1 delivers in excess of 900W and System #2 delivers around 650W.

When the MPPT temperatures (at the heatsink) are allowed to rise to 50 degC, System #1 output derates by almost 300W whereas System #2 does not derate at all.

I cannot understand why these two systems behave so differently. I noticed there was no answer to your question, did you gain any additional insight yourself as to why you could not observe any derating?

Cheers, Dean

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Alexandra avatar image Alexandra ♦ mariner62 commented ·
@Mariner62

You would need to eliminate the variable of hot solar panels also derating to eliminate them as a cause.

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mariner62 avatar image mariner62 Alexandra ♦ commented ·
Alexandra, no change in the panel temps. The only change was the temperature of the MPPT units. Cooled with a fan to get under 40 degrees, and no cooling allowed them to get to 50 degrees. Nothing else changed.
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Warwick Bruce Chapman avatar image Warwick Bruce Chapman mariner62 commented ·
No further insight gained.
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mariner62 avatar image mariner62 Warwick Bruce Chapman commented ·
Thanks Warwick.
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