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EVCS needs response to inverter temperature alarm

The EVCS integration works (nearly) seamlessly to prevent inverter overloads, but there needs to be a rollback protection to protect against inverter over-temp - especially since EV charging is by definition a long duration, high capacity load. At the moment, the EVCS/Cerbo integration works impressively well off-grid to ramp back EV charging to prevent an inverter overload due to current, but it ignores inverter temperature which means it will quite happily drive the inverter temperature up, up, up until the point of shutdown. Yes, the inverters will eventually reset and turn back on after they've cooled a bit, but then the cycle will repeat throughout the afternoon. For my system this wasn't a big issue in winter when things were cool, but it's definitely an issue now in the heat of summer. I'm currently trying to avoid the problem by dialing back the max EVCS charge current, but really this should be integrated into the system protections.

Consider this a kindly feedback from the field and protections improvement request :-)

evcs
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Hi, thanks for the feedback!

Normally, temperature and overload errors are connected together. The inverters are derating power based on temperature. Are you sure this is needed? Do you have an example of installation where this is happening?

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solarphil answered ·

Take a look at August 17th on c0619ab46187 - you can see four system shutdowns due to inverter overtemp conditions. I suspect that any existing inverter derate capabilities are only active when grid connected, but that's being ignored when off grid. That makes sense for a normal load, but not for the EVCS which is and should be a controllable load.

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Thanks, clear, we will add it.
What is your proposal, reduce the power or stop charging?

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solarphil answered ·

Good question. I think it would generally be preferred to reduce charging power early enough to keep the temperature from hitting the danger zone, similarly how the EVCS/Cerbo curtails charging in response to loads to prevent overcurrent. That way the car still receives whatever level of charge is possible for as long as possible given conditions.

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