# MQTT solar to charge settings



## Arden (Aug 5, 2019)

Hi all

Ordered my model 3 today 

I've seen the charge settings can be varied on the screen 

My solar system outputs MQTT messages just wondering if you can use this to set the charge level. Increasing the solar comsumsion 

Thanks Arden


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## Frully (Aug 30, 2018)

Greetings and welcome to the forum.

Currently there isn't a good (commercial) way to externally trigger the car to charge faster/slower or to a higher degree automatically based on solar system messages.

I've seen a hack where a guy tricks a tesla branded level 2 wall connector into thinking it is a slave on a multi-charger 'network' using a raspberry pi over rs485 - thus able to more smartly set the charge speed based on available green juice. It's a lot of hackery but technically works, if voiding a few warranties in the process and probably invalidating your house insurance.


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## garsh (Apr 4, 2016)

Frully said:


> ...if voiding a few warranties in the process and probably invalidating your house insurance.


Setting up a controller like this won't have any effect on your home insurance.


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## Frully (Aug 30, 2018)

garsh said:


> Setting up a controller like this won't have any effect on your home insurance.


YMMV. Insurance has many many clauses about everything attached to the house following UL/CSA/CE certifications...Any modification to the charge system would invalidate that rating if not specified in the documentation. The wiring in as a serial device would be fine but the stealing power to run the pi from the dc converter wouldn't. It's all down to who has the more effective lawyer in the end when staring at a burnt-down house.

Caveat -- It's extraordinarily beyond unlikely that a mod like this would CAUSE a failure but lawyers can be upsetting on basically every level.


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## JasonF (Oct 26, 2018)

Frully said:


> YMMV. Insurance has many many clauses about everything attached to the house following UL/CSA/CE certifications...Any modification to the charge system would invalidate that rating if not specified in the documentation. The wiring in as a serial device would be fine but the stealing power to run the pi from the dc converter wouldn't. It's all down to who has the more effective lawyer in the end when staring at a burnt-down house.


There is an easy way around that: If your home insurance gets squirrelly about modifying a built-in car charger, just add a NEMA 14-50 and plug it in. Then it's a plug-in appliance.

But yes, some insurers are ridiculous. I had to change insurers recently because the one I had insisted that I damaged and de-valued the house by installing solar panels (professionally, not by myself), and they were actually sent me legal documents with all kinds of threats of what they would do it I didn't remove them within 30 days. It was such an angry response, even my insurance agent was confused by it.

Additionally, modifying the low-voltage control circuit of a Wall Connector can't really cause a fire, it can only damage the Wall Connector, and only if you _really_ screw it up.


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## Griff (Aug 23, 2017)

I have an aunt who is an insurance executive in claims. I had a small fire which could have been due to an extention cord. When I asked her if the insurance company would be able to get out of paying because it was potentially my fault, she replied "if we had an idiot clause we'd almost never pay a claim"


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## sde1000 (May 23, 2019)

Arden said:


> Hi all
> 
> Ordered my model 3 today
> 
> ...


If you use a charger like OpenEVSE with its WiFi module you should be able to get it to change the power available to the car as the solar system output varies.


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