Electric car charger/heat/AC with no batteries.

[whiteshepherd]

For several years I have run a small solar backup system for my house. 700 watt solar panels, x4 235ah 6v flooded batteries (Lithium batteries weren't cheap then), and a 2500k pure sine wave inverter. It powers my modem, router, server for a free community web hosting service I run ( In Light of Us Community Web Hosting -"Solar Power" button on my site has pics of my solar system build). It also makes a good backup for when the power goes out letting me run medical devices, LED lights, fridge, phones, etc. I live off a very limited budget. But I live within my means and am always looking for ways to save money. My first dive into solar was some Harbor Freight panels I used to power a buck converter/water pump I had connected to a old spring pond with lots of fish in my back yard. The water pumped into a PVC pipe and through the roots of vegetables sitting in holes cut in the top of the PVC pipe then back into the pond. A simple system that worked well. I have some basic experience with computer programming and electronics.

I noticed how cheap used solar panels have become compared to batteries and was wondering on ways to use mainly panels? I have thought of setting up some panels to power a home made heat pump for heating/cooling basically turning the home heat/cool into the storage.

I also a few years back purchased a used Bolt EV Premier 2017 for pennies on the dollar (it just got a new battery too). I was thinking I could maybe build my own EVSE cable with a Raspberry Pi (there are already plans online for things like this) to do the communication with the car and manage the PWM. However my thought is I could use the Pi to monitor the PV amps produced. 1) Require sufficient PV amps to power EVSE for a continuous 60s before turning on relay to power inverter. 2) Regulate the amps fed to the car via PWM based on what amps the PV produces to prevent voltage crashing. 3) When amps are too low de-power relay to the inverter. The inverter would be protected from solar voltage variation by a buck inverter and some super caps I have around to the house to help prevent low power "chatter". That's the idea so far. Question though is there anything like this already out there that does this for a reasonable price? That would save a lot of work. If not are there examples of what others have done I can read up on? I haven't found any yet. Any knowledge gained can help along the way. Thoughts?

 

[time2roll]

I would look to OPEN EVSE to see what is available for communicating when to charge utilizing excess solar power. This all started back in 2011 as an open source alternative to overpriced charging stations when the first LEAF was produced.

https://www.openevse.com

The My Nissan LEAF forum might be of help. Many pioneers doing reverse engineering 10+ years ago.

https://www.mynissanleaf.com

 

[Swing]

By now quite a few of home charging points have a solar only option. But that is always grid connected, taking energy what otherwise would be exported to the grid.
I have the European version of a Bolt too (waiting for battery) and want to do that too.

However, I noticed, that the SmartEVSE works much in the same way as other closed charging points, it has a sensorbox to get that extra data. What I would like to see is some kind of interface, a programmijg API or PWM port or whatever to directly drive it.

But for offgrid you will always need to have a battery system that can power this for a few minutes, because of delay in fluctuations.
For me that is okay.

But since I am exporting solar to the grid anyway I might as well take the easy route.

I have been thinking to buy one of these 230v mobile socket chargers which can go up to 3.7kw, or even 5.5 or 7.2kW, with buttons to adjust the rate. Then just open it up, hook up a Raspberry Pi to drive the buttons to let it switch between 6, 10, 16 (and possibly 25 and 32) amps.
Of course that is with steps, not as seamless as with PWM, but it will work quite good in general.

Edit: basically buying something like this and modifiying it taking buttons and leds as output/input. And this ine can do in steps of 1Amp at 230v so that means steps of 230W, which is fine for me.