[ozkona]

We have a Kona EV and solar panels and have just installed a Powerwall 2. It's winter here in Australia and we are charging our EV from the trickle charger (we are retired and the trickle charger is sufficient for our needs) and the PW2 is also charging, but when the clouds roll in and there is less than 2KW from solar, the PW2 discharges to charge the Kona. Not what we want and not very efficient, we want the PW2 keeping its power for overnight use.
Any PW2 and Hyundai EV uses out there that have solved this problem?

 

[IanMurray]

I think there is a minimum charge amount for your Konas, when my solar panels are working in grey cloudy weather running the house & charging the car, car charging draws a bit of power from the grid, over a day this might be a couple of kWh, I wonder if there is perhaps a 2kW minimum (or so) for the Kona to charge.

 

[Gadget Geek]

We have a Kona EV and solar panels and have just installed a Powerwall 2. It's winter here in Australia and we are charging our EV from the trickle charger (we are retired and the trickle charger is sufficient for our needs) and the PW2 is also charging, but when the clouds roll in and there is less than 2KW from solar, the PW2 discharges to charge the Kona. Not what we want and not very efficient, we want the PW2 keeping its power for overnight use.
Any PW2 and Hyundai EV uses out there that have solved this problem?

Hi there.
I had the same problem with my Powervault, so I built an extension lead with a light sensitive switch in it. When the clouds roll in, the granny charger switches off,and when the sun comes out, it switches back on . . . perfect!

 

[Electra Glide in Blue]

I think there is a minimum charge amount for your Konas, when my solar panels are working in grey cloudy weather running the house & charging the car, car charging draws a bit of power from the grid, over a day this might be a couple of kWh, I wonder if there is perhaps a 2kW minimum (or so) for the Kona to charge.

I have been using the granny a lot. Like ozkona I have been using the trickle charger exclusively as I am doing few miles. Unlike ozkona I am yet to install powerwall..

The Kona will charge much below 2kW, as low as 600w on the 6amp setting with the car set to minimum or 2200w at 10amp and car on max. With settings in-between

. It takes days to charge at 600w though!

 

[Electra Glide in Blue]

Hi there.
I had the same problem with my Powervault, so I built an extension lead with a light sensitive switch in it. When the clouds roll in, the granny charger switches off,and when the sun comes out, it switches back on . . . perfect!

I like that idea, can you tell me please what switch you used.

 

[Gadget Geek]

I like that idea, can you tell me please what switch you used.

I was going to build it from scratch as I have a City & Guilds in electronic servicing, but when I searched for the components on line, I found a light sensitive module and a 30 Amp relay module. It can be put together without soldering and can be put together by someone with a limited knowledgw of electronics. (Just remember the relay switches mains voltage, so take usual precautions).

First of all is a list of components needed. I’ve included the web address of some of the components, but you may wish to search for your own.

LC Technology 5V 1 Channel Relay Module 250V AC 30V 30A DC https://fluxworkshop.com/collections/bh-relays-solenoids/products/bhaa100045-5v-30a-c-nc-lc-blue

Weatherproof IP54 Inline Socket https://www.amazon.co.uk/dp/B006X09WDW/ref=pe_3187911_189395841_TE_dp_1

LDR Photoresistor Light Detection Sensor Module Dependent Resistor Arduino PIC LDR Photoresistor Light Detection Sensor Module Dependent Resistor Arduino PIC | eBay

13 amp plug.

A 5 Volt power supply with enough current to switch the relay. (? 3Amps)

A 3 pin, 3 line connector.

A 4 pin, 4 line connector.

3 amp connector block.

10 amp connector block.

13 amp 3 Core Flex 1.5mm, 5 metres or so.

Waterproof plastic box. Clip and close lunch box.

Telephone extension cable with connectors.

To complete this project, I am assuming some prior knowledge of basic hobby electronics. You will be using mains voltage electricity, so if you are at all unsure then please defer to someone who is. Anyone with a knowledge of electronics should be able to follow the attached circuit diagram.

The switch is in two parts which will connect together with the telephone extension socket and plug.

Photo sensor

Firstly you need a clear, plastic container to house the LDR Photoresistor Light Detection Sensor Module. I found an empty plastic test tube in the bathroom which had contained bath salts. You can buy them on Amazon, or a small plastic bottle will do.

For the connecting cable, I used a telephone extension cable with connectors. Cut the cable about a foot from the female connector. Bare the ends of three of the four wires.

Drill a small hole in the container and feed the cable through. Twist the ends of the telephone wires with the ends of the 3 pin connector which plugs into the LDR Photoresistor Light Detection Sensor Module. You can solder, shrink wrap or wax the connections. I used some bubble wrap to protect the module when I finally assembled it. Leave the module out for the moment as you will need to adjust the trigger level with the potentiometer.

Relay unit

You will need a weatherproof container large enough to hold the relay, 5 volt power supply and connector blocks. I used a waterproof, clip shut lunch box, but any weatherproof container will do.

Drill two holes at opposite ends of the box, just large enough for the 3 core flex to be forced through, and a small gap to feed through the other part of the telephone cable.

The 5 volt power supply I used was one I had in the garage from an old external ZIP drive for a computer. (Remember those?) I cut the plug off the flex and bared the ends to fit in the 10 amp connector block with the mains, 3 core flex. The ends of the 5 volt flex were bared and fitted in a 3 amp connector block with the ends of the telephone extension cable.

Note: Make sure your 5 volt power supply has enough amperage to trip the 30 amp relay. (I had to add another relay to trip the main relay.)

There is now one spare wire in each part of the telephone extension cable.
In the LDR Photoresistor Light Detection Sensor Module, it is connected to the terminal marked DO.

On the relay, it is connected to the terminal marked with a +, next to the VCC terminal.

Use the circuit diagram above to connect the wires into the connector blocks. You will need two extra wires to connect live mains into NO, and COM to live mains out.

Check all connections for stray strands of wire etc before powering up. If all is working correctly, there will be a red LED on the relay module and the photo sensor module. If you shine a torch on the photo sensor, or put the module in the sun, a green LED will light on both modules, and you will hear a click when the relay activates. I used a table lamp as a test load when I was setting up the sensitivity of the photo sensor.

This is only an example of how I built a photo sensitive switch. It is not a definitive set of instructions. Anyone who decides to try and build their own photo sensitive switch, does so at their own risk.

It works great and in April I got 61.44 kWh of solar, May 88.48 kWh, and June 62.72 kWh. That's around 980 miles for free!

 

[mikeselectricstuff]

Instead of switching the mains, another option would be to interrupt the CP line from the charger to the car

 

[Gadget Geek]

Instead of switching the mains, another option would be to interrupt the CP line from the charger to the car

Yes, that would be a lower amperage. You would have to buy a type 2 plug and socket though which I'm guessing would be more expensive than the £25 for the set up I used, but safer for someone not happy using mains voltage.

 

[Kingpleb1]

The simplest way is to get one of the units that you would normally use for an immersion heater.

Something like this.

How Do Solar Power Diverters Work? - TheGreenAge

Solar power diverters prevent any electricity surplus (provided by solar panels or wind turbines) from being exported back to the grid - find out why!

www.thegreenage.co.uk

SOLiC200 Solar Immersion Heater Controller

The Award Winning SOLiC 200 from Earthwise Products Ltd automatically converts energy generated by existing PV panels into hot water by diverting excess solar power to the immersion heater before it’s exported to the national grid.

www.itstechnologies.shop

Stick a 3 pin socket on the end of it to plug the granny charger into, and wire it into a house socket instead.

 

[Gadget Geek]

The simplest way is to get one of the units that you would normally use for an immersion heater.

Something like this.

How Do Solar Power Diverters Work? - TheGreenAge

Solar power diverters prevent any electricity surplus (provided by solar panels or wind turbines) from being exported back to the grid - find out why!

www.thegreenage.co.uk

SOLiC200 Solar Immersion Heater Controller

The Award Winning SOLiC 200 from Earthwise Products Ltd automatically converts energy generated by existing PV panels into hot water by diverting excess solar power to the immersion heater before it’s exported to the national grid.

www.itstechnologies.shop

Stick a 3 pin socket on the end of it to plug the granny charger into, and wire it into a house socket instead.

OK if you can afford it. £186 vs £25. Also, some diverters conflict with the storage battery software and the solar gets exported to the grid instead.

 

[Electra Glide in Blue]

The simplest way is to get one of the units that you would normally use for an immersion heater.

Something like this.

How Do Solar Power Diverters Work? - TheGreenAge

Solar power diverters prevent any electricity surplus (provided by solar panels or wind turbines) from being exported back to the grid - find out why!

www.thegreenage.co.uk

SOLiC200 Solar Immersion Heater Controller

The Award Winning SOLiC 200 from Earthwise Products Ltd automatically converts energy generated by existing PV panels into hot water by diverting excess solar power to the immersion heater before it’s exported to the national grid.

www.itstechnologies.shop

Stick a 3 pin socket on the end of it to plug the granny charger into, and wire it into a house socket instead.

I have one of these solar controllers for my thermal store. If I repurposed this for charging it would would not work as intended I suspect If you are also trying to charge a power wall.
Roll on V2G.

 

[Edd Beesley]

The simplest way is to get one of the units that you would normally use for an immersion heater.

Something like this.

How Do Solar Power Diverters Work? - TheGreenAge

Solar power diverters prevent any electricity surplus (provided by solar panels or wind turbines) from being exported back to the grid - find out why!

www.thegreenage.co.uk

SOLiC200 Solar Immersion Heater Controller

The Award Winning SOLiC 200 from Earthwise Products Ltd automatically converts energy generated by existing PV panels into hot water by diverting excess solar power to the immersion heater before it’s exported to the national grid.

www.itstechnologies.shop

Stick a 3 pin socket on the end of it to plug the granny charger into, and wire it into a house socket instead.

That's a bad steer. They used modified sine wave and CANNOT power electrical loads other than heater elements.

 

[Edd Beesley]

We have a Kona EV and solar panels and have just installed a Powerwall 2. It's winter here in Australia and we are charging our EV from the trickle charger (we are retired and the trickle charger is sufficient for our needs) and the PW2 is also charging, but when the clouds roll in and there is less than 2KW from solar, the PW2 discharges to charge the Kona. Not what we want and not very efficient, we want the PW2 keeping its power for overnight use.
Any PW2 and Hyundai EV uses out there that have solved this problem?

There are products available such as Zappi in the UK which measure excess solar and set the appropriate charge rate in an EVSE. also plans for it to DIY at Open EVSE OpenEVSE / EmonEVSE Setup Guide

 

[Kingpleb1]

That's a bad steer. They used modified sine wave and CANNOT power electrical loads other than heater elements.

My dad has a similar one and it works fine powering other things like a kettle, UPS, granny charger when needed.. it works best when the battery is full though.

Only other option really is a Zappi or such.

 

[Gadget Geek]

You can also get the Ohme Cable Charger which is a smart granny charger.

https://ohme-ev.com/

Downside is that it cost £400.

 

[Steve Ashton]

The simple physical way to stop your PW2 from discharging when your car charges is to take the EVSE feed off before the Gateway CT clamp. If you have a Gateway2 the the EVSE has to be fed before the GW2.
An alternative is to set the PW2 Customise> Advanced > balanced and then set the price schedule to off-peak and the PW2 should not support loads in most cases.

 

[ozkona]

Fantastic idea from Gadget Geek but I don't have the skills to build it. The Zappi would seem to work but is an overkill for me at present and they are $1400 in Australia, and all sold out at present. I do have the granny charger attached to a TP Link smart plug so I have been turning it on when we have excess solar, but the Powerwall keeps jumping in when clouds roll in.

 

[ozkona]

The simple physical way to stop your PW2 from discharging when your car charges is to take the EVSE feed off before the Gateway CT clamp. If you have a Gateway2 the the EVSE has to be fed before the GW2.
An alternative is to set the PW2 Customise> Advanced > balanced and then set the price schedule to off-peak and the PW2 should not support loads in most cases.

I was posting just as you wrote this. I will need to talk to our PW installer re your GW2 suggestion. We are on a flat rate tariff here and anyway I don't want the PW to import from grid (most power in our state from brown coal). Wouldn't balanced cause the PW to import from grid? I am a 1 week PW novice hence my question.

 

[Steve Ashton]

I was posting just as you wrote this. I will need to talk to our PW installer re your GW2 suggestion. We are on a flat rate tariff here and anyway I don't want the PW to import from grid (most power in our state from brown coal). Wouldn't balanced cause the PW to import from grid? I am a 1 week PW novice hence my question.

Generally 'Balanced' just suspends the PW while 'Cost Saving' is more likely to charge the PW during off-peak (depending on SoC and history). It isn't a hard and fast rule as the logic in the GW is sometimes obscure.

 

[ozkona]

Generally 'Balanced' just suspends the PW while 'Cost Saving' is more likely to charge the PW during off-peak (depending on SoC and history). It isn't a hard and fast rule as the logic in the GW is sometimes obscure.

Thank you for information Steve. We'll give it a go.