Inverter derating

I doubt that, Hot air rises, with the help of the fan the hot air is also forced out of the enclosure, if you look at the layout of the enclosure, the MPPT is already right on top with a plate between it and the inverter side. The chances of the heat transferring imo is very slim unless the fans blow down and not up…

Where do I find the inverter temp for the multi on the gx… Searched through all the mqtt settings… See the mppts values but not the inverter…

It’s not available, unfortunately…

Pity. I would have thought that is a good one to have… Must be measured… (Hint for future releases…:wink:)

My fok Marelize … daar leer ek nou iets … SSH werk op Win10 “as is”.

As I understand it it is simply not available on VE.Bus. Adding it would require a modification to the entire pipeline (Multi firmware, VE.bus driver, log it to vrm, make it available via modbus-tcp, show it on the gui, etc). Also, it’s not a neutral element. Adding it will surely cause more questions for the support staff… :slight_smile:

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I vaguely remember they added it to an update in April 2018, somewhere there.

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I agree with this, but heat is transferred by means of convection, radiation and conduction. I’m not sure how the Multi looks inside, but radiation heat goes in all directions and conduction would move inside materials.

Guess it could still be possible that the radiation could heat it up. Like standing in front of a braai. Typically you feel radiated heat, not the warm air.

Beyond my level of knowledge but can an apparent sooner than anticipated derating (i.e. 25ºC is not where one might expect the inverter to derate yet to Tariqe’s level?) be influenced/explained by type/s of load (crest factor?)? So the inverter temp is not high because of ambient temp but the type of load makes the inverter work harder?

I have a Goodwe, it does not have a fan, so now with ambient temps around 35C, the inverter, pulling max power from pv, gets up to 55C.

I put a small bedroom fan to blow onto it and it reduces the temp down to 45…Makes me wonder if an internal fan of sorts would actually e a good idea.

It does not seem to derate, even at 55C, it still pulls 4.8kW from pv.

I created some flow to avoid temperature issues and it seems to work well. Ideally I would of wanted the MPPTs not to be mounted underneath the inverter, as it is likely sucking in some of that hot air as well, but I only realised that afterwards.

Is it only the one fan? If so, can your system really run at full power for extended periods?

As a basic rule of thumb, you need around 600m³/hr of air flow to cool 1000W of dissipation with 5°C temperature rise.

The goodies in the cupboard need to get rid of around 1200W at full power, which would typically require at least 3 150mm ventilation fans. A single fan would see the interior temperature ~20°C above ambient, which would limit max continuous power.

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Define extended periods? What is the benchmark? I normally can run 4300 without issues…

I have not experienced such a huge ambient difference, even without the fan.

Defining ‘extended’ periods is difficult, as it depends on a lot of factors. But typically it would be 20-30 minutes and longer.

At 4300W output, your inverter will be dissipating around 850W, which would give you a 10-15°C temperature increase with only one fan.

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Well, have it from the horses mouth that the Easysolar II GX with the built in mppt is the same as a standard Multiplus II when it comes to de-rating !!!

Today the ambient temperature was 16, not 26 and the inverter was still de-rating, if I clamped a pc fan to the bottom of the inverter below the cooling slots, do you guys think it would make a difference

How hard was the inverter working at the time?
Was batteries being charged when the house loads where powered?

By how much did it derate?

the load was 2250 watts AC, the batteries were fully charged, batteries were not being drained, but grid was supplying approximately 300 watts.
will a pc fan clamped to the bottom air vents make a difference

Try it …

I use a large fan to circulate the air around the entire system on very hot days.

Anything that takes heat away from a component will always help.
Heat is one of the biggest influencers on any electronics.

I added extra heat sinks to my MPPTs and they can run full amps for hours.
You can see the aluminium plates that my MPPTs are mounted too in these pics

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