Turning a dumb car charger into a smart one

[BBBB]

I have an EV charger that was installed before my PV array and is not a smart charger. Does anyone know if it is possible to turn it into a smart charger so that it will draw "spare" solar power that would otherwise be exported and/or the excess power that cannot be handled by the inverter( I have a 6kW array and a 5kW inverter)?

 

[sebdehne]

The "smart" part of a EV charing stations is that it should be able to regulate the power according to your solar input (or other parameters such as grid prices etc).

If you are good with electronics and can write code - then you could always build your own, as I did: https://dehnes.com/electronics/2021/03/31/dehneevse_charging_station.html

Otherwise, there are commercial solutions like https://www.victronenergy.com/accessories/ev-charging-station

 

[newbostonconst]

Sure...could use Smartthings and current sensors and relay....

 

[BBBB]

If you are good with electronics and can write code - then you could always build your own, as I did: https://dehnes.com/electronics/2021/03/31/dehneevse_charging_station.html

Otherwise, there are commercial solutions like https://www.victronenergy.com/accessories/ev-charging-station

Thanks very much for your reply but those both look like ways to build or buy an EV charger. I already have a charger, I just want to integrate it into my solar setup so that it draws when excess power is available.

 

[sebdehne]

Thanks very much for your reply but those both look like ways to build or buy an EV charger. I already have a charger, I just want to integrate it into my solar setup so that it draws when excess power is available.

The question is wether your existing charger support adjusting/regulating the power during charging in any way.

 

[BBBB]

The question is wether your existing charger support adjusting/regulating the power during charging in any way.

No, it doesn't. That is what I am hoping to change...

 

[newbostonconst]

No, it doesn't. That is what I am hoping to change...

You don't have to adjust/regulate the power....an on and off relay should work.

If you are making over this much power turn the relay one if not turn relay off.

But if you want the more complex version I would buy a premade one imho....

 

[BBBB]

You don't have to adjust/regulate the power....an on and off relay should work.

If you are making over this much power turn the relay one if not turn relay off.

But if you want the more complex version I would buy a premade one imho....

Thanks. Do you have a suggestion for a premade one. I have searched on line and not been able to find anything suitable.

 

[curiouscarbon]

I have an EV charger that was installed before my PV array and is not a smart charger. Does anyone know if it is possible to turn it into a smart charger so that it will draw "spare" solar power that would otherwise be exported and/or the excess power that cannot be handled by the inverter( I have a 6kW array and a 5kW inverter)?

hello!
welcome to forum

may i ask how many amps the charger is rated for?

if you only need 10 amps 120v ac or so, this device may be able to help to this goal : https://www.sparkfun.com/products/14236


basically to turn it smarter, it is possible to connect the charger via an AC relay that will flip the outlet power on and off based on your requirements.

the one above can do 10 Ampere 120V AC switching at least, and the green plug on the side is where the on/off signal is connected.

an arduino or something monitoring the voltage of the battery and connecting/disconnecting the charger based on battery voltage might work.

happy to assist further if this option sounds interesting.

good luck with this project!

 

[curiouscarbon]

I have an EV charger that was installed before my PV array and is not a smart charger. Does anyone know if it is possible to turn it into a smart charger so that it will draw "spare" solar power that would otherwise be exported and/or the excess power that cannot be handled by the inverter( I have a 6kW array and a 5kW inverter)?

yes, this spare power use is possible ?

connecting the charger when battery bank is above a certain voltage, and disconnecting charger when battery voltage below a certain voltage, is a simple way to achieve this.

ensuring the relay switches slowly can help a long operation life. basically a programmed one minute delay between switching can go a long way. check out wikipedia hysteresis for more info. relays for switching power on and off only last for X on/off cycles, so this extends the life of the "smartifying" circuit

 

[curiouscarbon]

please post a photo of the charger, or maybe the manufacturer and or model info, any specifications will help ! ??

 

[curiouscarbon]

Thanks. Do you have a suggestion for a premade one. I have searched on line and not been able to find anything suitable.

sorry, not aware of a premade one.

but with a few hours of hacking, combining an arduino with a relay can provide good functionality.

happy to help with the coding and steps!

 

[BBBB]

sorry, not aware of a premade one.

but with a few hours of hacking, combining an arduino with a relay can provide good functionality.

happy to help with the coding and steps!

Thanks,

The model that I have is a 2-way Rolec Basic Charge. I have the 1-phase model so 230V and 63A https://www.rolecserv.com/ev-products/BASICCHARGE.

 

[curiouscarbon]

Thanks,

The model that I have is a 2-way Rolec Basic Charge. I have the 1-phase model so 230V and 63A https://www.rolecserv.com/ev-products/BASICCHARGE.

thank you for this info. very helpful

unfortunately the previous switch only supports 120VAC and 10A, so it would not function for this use case.

 

[curiouscarbon]

the rolec basic charge says it supports ethernet, so maybe it is possible to look up how to send it a message over wired computer network to connect/disconnect the charging with software only.

otherwise, connecting a relay before the charger, and cutting off the power to the charger programmatically is a mostly dependable method

 

[BBBB]

the rolec basic charge says it supports ethernet, so maybe it is possible to look up how to send it a message over wired computer network to connect/disconnect the charging with software only.

otherwise, connecting a relay before the charger, and cutting off the power to the charger programmatically is a mostly dependable method

Thanks.

I am able to turn it on and off remotely but what I hope to do is to plug in a car to the charger and have the charger detect when I am exporting excess energy to the grid and divert it to the EV charger. I already have a unit that does this for my hot water and was hoping to extend it to the charger.

 

[400bird]

You might contact the vendor if your EVSE. They are your best hope for an off the shelf solution.

Otherwise, as curiouscarbon mentioned, you might get there with some DIY programming and an external microcontroller.

If you're ok to supplement/replace your current EVSE there are more options.

 

[RCinFLA]

What is your definition of 'EV charger'

Most home EV charging ports for EV auto chargers are not really chargers. They are just smarts in an AC outlet to communicate with the auto to tell it what the maximum AC current is allowed to be drawn by EV auto charger, which is actually in vehicle. It is setup to allow maximum AC amperage draw based on the main AC panel breaker amperage it is connected to.

EV charger for smaller 'EV's' like an electric bike may be an actual charger.

 

[Solar Guppy]

Thanks.

I am able to turn it on and off remotely but what I hope to do is to plug in a car to the charger and have the charger detect when I am exporting excess energy to the grid and divert it to the EV charger. I already have a unit that does this for my hot water and was hoping to extend it to the charger.

Even if you purchase an EV charger that has an adjustable current limit ( it is a simple PWM signal, part of the J1772 Standard ), you can't have two of these without these load devices also talking to each other.

Consider this, you have the hot water controller see 1kw excess PV generation, so it loads an additional 1kw to heat the water, at the same time your smart EV charger, does the same thing for the car, now they see a 1kw to much being pulled, they will hunt / oscillate when both are active, and even with a single device, you are going to need some type of hysteresis on the control. The only way for this to work would be a central controller.