Nice work, the graph speaks for itself. Very impressive. I hope to do the same thing using openEVSE.
So far I’ve successfully been able to vary the charge rate of the openEVSE using RAPI commands:
I’ve just been reading up on the charging efficiency of charging a Nissan LEAF. It seems the charging is more efficient at higher currents.
Here is the full report
Interesting to know, so when reducing the charge rate when diverting from solar maybe it would be best to have a 2Kw cut off?
Please take in account the North American Standard, these tests are made at different frequency and voltage. The chargers for European market operate at different settings and that can have impact on the tests.
Practically all chargers are terrible at low voltage & low amperages. In Portugal and UK the minimum would be 230V / 240V at 6A that scores a efficiency above 80% and that’s fine for diverting in my opinion.
Also L1 and L2 are mutually exclusive, so a cutoff would has no effect, i think!
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Just seen on Indiegogo there is a company crowdfunding a solar PV charge diversion controller. Looks nice, I like how they have defined three modes of operation:
This is possible using openEVSE at the moment. I’m working to try and make it easier. It would be nice to have an EV specific Emoncms dashboard to show in real-time who much power is being diverted from solar.
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A custom dashboard would be awesome! And if you could integrate periodic feedback from carwings with the 12 SOC bars would be crazy cool!
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I’ve just started a new thread to document my current progress using NodeRED and MQTT to control OpenEVSE charge rate based on solar PV production:
Hi All,
Our Charger uses Open Charge Point Protocol (OCPP) version 1.5 over JSON, do you think this could be intergraded in to the system?
Thanks
Paul
Hi Paul,
I’ve never heard of this OCPP Protocol, can you elaborate more on this?
Regards,
Sorry Paul, you need to do better than that!
GitHub - NewMotion/ocpp: Open Charge Point Protocol perhaps that help you along it also point to other references
I’m sorry i’m not the one that needs help lol
I’ve been reading about OCPP - thanks paul for that, i had no idea what it was - and it is not Open like Openenergymonitor, it’s open for the companies that what to be part of it.
I found no server, and no implementation ready to test, it’s all about the possible messages that a unknown central server makes to the charging station. Actually V1.6 can also change pilot signals, however only V2.0 (draft) brings full encryption and that seem really late.
- For a personal charging station it’s completely overkill and useless.
- For a commercial project it’s perfect
- For a community driven charge infrastructure would be interesting ( but probabily illegal in most contries)
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Using a Solar Cell to Control an EVSE (via the EPC)
Hi All,
I have not read all the way through this thread so forgive me if the subject of this post has already been mentioned or is not relevant.
People trying to match their EV charging current to their PV output (to minimise exported energy) may wish to consider using a small solar cell in proximity to the EVSE with a reasonably clear view of the sky. On the basis that the solar cell will be illuminated in approximate proportion to the PV array and at the same time (roughly), this may be a lot easier to implement than other methods especially when the EVSE is remote from the PV and/or its control electronics (ie a clamp-on inductive-type sensor is inappropriate/too expensive).
It would certainly be a useful addition to what has already been submitted here if one were interested in using the Viridian (Mainpine) EPC which I sell through my webshop at EVBitz.uk (related plug so I hope it doesn’t upset the moderators).
Regards, Martin Winlow.
Director EVBitz.uk
Hi,
I understand your point, however in my opinion the best way is to have a remotely controlable EVSE, like the one i’m developing here (EVSE Colaborativo - Clubeletricos.com).
With this EVSE, the integration is direct, since it talks the same language as the IoT platforms like Node-RED. To make everything work we just need a bidirectional energy sensor and a raspberry pi ( a emonPi) and we’re set.
There are other EVSE that can change Amps, instead of adapting a solar cell to change the current based on the intensity, maybe it’s easier to adapt a ESP8266 to control the amps and provide remote control via WiFi. OpenEVSE is a great example of this approach. It should’t be hard to integrate ESP8266 with the Viridian EVSE.
This only works if you can assume that all the solar is there to be diverted. In my set-up I am only diverting - or trying to - the spare solar that is not already being used in the house, i.e. what I would otherwise export.
Hi Martin
https://openenergymonitor.org/forum-archive/node/10805.html
The above link is to my first build of a ‘surplus power’ charger using your Viridian EPC and a modified emontx v2. It worked very well and I even got several enquiries as to whether I would build a commercial version. It’s a very accessible solution for the electronics DIYer.
Recently I invested in an OpenEVSE unit as it is more customisable. My new EVSE will wait until the Tesla Powerwall home battery is 90% charged before charging the EV using surplus solar. I’m also going to include an Economy 7 mode. I’m almost there - Node-RED was a learning curve!
Hi Stuart,
Thanks for the update. I hope it goes well and let me know if you do come up with a commercial version as I have had a fair amount of interest from people wanting this sort of facility. So, I would be interested in selling it.
Regards, Martin.
EVBitz.uk Limited
Wychwood
Widford Road
Much Hadham
Herts
SG10 6EZ
UK
Companies House Number: 09374896
Tel: 07788 138 413
Email: [email protected]
www.EVBitz.uk
Hi Stuart, great build, can you please explain how the power pack delivers energy to the consuming equipments?
Hi everyone,
We have been busy working on a significant update for OpeneEVSE Wifi which now includes full in-built solar PV diversion capabilities i.e. all diversion calculations are made on the ESP unit inside the OpenEVSE, nodeRED is not required. The solar data comes from an emonPi via MQTT.
Solar PV divert can be enabled by selecting Eco mode in the UI web page.:
We are keen to get some real work testing from other users, if your interested please see thread:
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