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michaeldale avatar image
michaeldale asked

Victron MPPT Temperature Limit 40c

Hi All,

I have a Victron MPPT BlueSolar 75/15 in my shed.

Once the shed gets to 40c inside (it is hot in Australia) the Victron will stop pulling power from the solar panels.

Load still works and there are no error lights etc (still shows float/bulk LEDs as normal).

Is there anyway to change this setting as is means I am unable to pull power in from the panels for a large percentage of the day.

MPPT Controllerstemperature
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Hi Michel, I have the same problem with mppt100/50 i found out. And also with a victron 220/24 battery charger but there i could cut out the sensors.

What are the other regulators that you have that don't give trouble in the tropics? And are you happy with the other ones?


Thanks, Marco.

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4 Answers
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

A 40 degree room could easily mean a 60+ degree charge controller.

Perhaps try cooling it with a fan.

There is no override for the temperature protection de-rating. It’s to stop the unit from failing or worse.

It’s rare you will find an electrical appliance that is happy operating at more than 60 degrees for years on end.

There is also your batteries to consider, they are designed to operate closer to 25.

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Manny electronics in the engineroom, gets easy 50c. Only victron units can't handle the heat in the tropics. But its made for the north european market i think.

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michaeldale avatar image
michaeldale answered ·

Thanks for the reply. Do you know if the bigger units can handle heat better?

I have 3 different charge controllers in the shed and only the victron isn't able to deal with the heat.

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Yup, the bigger the unit, the bigger the heat sink and heat disappation capacity. But really, a bit of additional airflow might make all the difference and would be a lot better value.


Another thing to check if you can is the log into the unit with VictronConnect. See if there are any notices there.

40 in the shed could mean 70 at the solar panel and there might be some other issue with voltage reduction and the margin required.

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marco avatar image
marco answered ·

Hi Michel, I have the same problem with mppt100/50 i found out. And also with a victron 220/24 battery charger but there i could cut out the sensors.

What are the other regulators that you have that don't give trouble in the tropics? And are you happy with the other ones?


Thanks, Marco.

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Mike Dorsett avatar image
Mike Dorsett answered ·

I also have a similar problem with an MPPT150-70 unit, with the output being limited to ~50A rather than 70A. Ambient temperatures are around 26 - 28C.

Given the unit is delivering about 2kW, and assuming 95% efficiency, the unit should be dissipating about 100W. The heatsink in this case is NOT screwed flat to a wall, but spaces a little distance from it (this will improve the dissipation.

The heatsink temperature is about 60C so 32 degrees above ambient. This gives the thermal resistance of the heatsink as about 0.32 degrees per watt - which for that size of heatsink in a non-optimal convection cooled environment is good performance. Assuming 4 devices inside are dissipating the power (Similar to the 100/50 unit - this one has not been opened as it is under warranty) - then each device is dissipating ~25W. If the internal temperature of the unit is 75 degrees as indicated by the telemetry, then this is 15 degrees above the heatsink temperature giving a thermal resistance of 0.6 degrees/W for device to heatsink. Junction temperatures will be higher than this, and yes these need to be kept to <125C in order to achieve a respectable life time.

Whether this could be improved economically is a question for the Victron Engineers, BUT I feel that the thermal management of the unit should be designed to allow full operating power at a 25 degree ambient temperature, OR proper provision made for mounting a cooling fan. This would be a switched power output (at Battery voltage), and threads or bracket for the heatsink to accommodate the fan.

@mvader (Victron Energy) @Guy Stewart (Victron Community Manager)

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