would be useful to see the design, build , tutorial etc

feel free to post with the relevant disclaimers

"if in doubt consult a qualified electrician", "check local electrical regulations", "Do this at your own risk" etc.

 

Good idea.
I'll attach the circuit diagram now and put together a step by step guide.
Watch this space.

Please be aware that this project uses mains voltage electricity! If you are at all unsure then please defer to someone who is.

 

so you appear to be using a light dependant resistor to trigger a relay to start / stop charging?

 

That's right. You can set the sensitivity to match the output of the panels. I've set mine to switch on at 1.5 kW. With the house using about 0.5 kWh, I'm only paying for half a kilowatt at low light levels and it's free when it gets up to 2 kWh. In full sunshine I'm charging the car and exporting to the grid. I put the light sensor on top of the car angled to the south. It works really well. I'll post some photos tomorrow.

 

That's neat. Are you using the car Low charge setting with the podpoint and hooking in to the podpoint input power? I wasnt able to make it work on the low charge setting at home. Must try it again.

Or are you breaking into the wiring to a socket for the "emergency" charger. (Thinking about it... this can only be set to low charge manually afyer each on cycle.)

Podpoint put me on their development email list and had mentioned solar control a year ago. Obviously, havent heard anything yet.

I'm using a Solec200 to divert solar excess to the hot tank. I was using a solar iboost.

 

Hi BlueNev,
What I've produced is an extension lead for the 13 amp trickle charger to plug into. This extension lead has the photosensor and relay built into it. So there's no messing with the Pod Point (and the warranty). No opening up of existing chargers and splicing into anything, it's just an external socket to plug your trickle charger into which switches on and off with the sunshine. I wanted to keep it as simple as possible. All will become clear when I post some photos.

 

Great! Looking forward to the photos.

 

Okay, as promised. The photos of my project.

1 shows the relay unit with extension lead, the weatherproof socket and the telephone connector.

2 shows the connector blocks sitting on top of a 5 volt power supply.

3 shows the LDR Photoresistor Light Detection Sensor Module Dependent Resistor Arduino PIC inside a plastic tube which originally contained bath salts. (It was the perfect size. I just drilled a tiny hole and fed the telephone cable through before connecting it to the 3 pin 3 way socket.

4 shows a plastic bottle cut off at an angle to act as a base.

5 shows the photosensor on top of my car.

6 shows it from a distance.

At the moment the sun is out and the car is charging. Its currently costing me 8.8 pence an hour, but it goes up and down as the intensity of sunlight changes. Most of the morning I've been charging and exporting.

 

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 https://www.ebay.co.uk/itm/362145909694

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. (Photo 3 in previous post.)

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. (Photo 2)

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. (See attached circuit diagram)

Use the attached circuit diagram 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.

 

my only comments and concerns are

10amp choc block connector, this should be 15 or 30 amp

1.5mm cable rated at 13 amp, better would be 2.5mm cable rated at 25amp this would give a greater safety margin for overheating and lower losses

if the cable /device is capable of being plugged into a 13amp supply it should be capable of safely taking the full 13amp load

its much better to over engineer this sort of solution and have nice safety margin

 

Fair comment. I checked the current draw on my charger and it was 9.2 amps, so I knew it was OK.
If you are going to attempt to build one yourself, check the current draw on anything you plug into the unit.
The cable heating is minimal, slightly warm to the touch.
But yes, a safety margin is always the best option.

 

Surprisingly cheap to buy the components... both bits cheaper than an Energi mug.

So you set a minimum solar supply threshold before the relay cuts in and delivers the max 2.5kwh or 10A (High level) on the 3 pin UK charger. As you say it was pulling 9p/hr or 0.8kwh off the grid during your photo shoot.
Ideas for an upgrade... current sensor pic so you can assess actual mains usage/export.

Zappi has 3 modes of charging with a minimum of 6A or 1.5kwh.
1 - eco - adjust for household use
2 - eco+ pause if using too much mains
3 - fast - dont care how much mains

Mine - all excess solar goes to hotwater unless...
1 - sun's out but car not needed... Low or none
2 - suns very good. L, M, H or Full charge on podpoint.
3 - going out in 30 mins or sun not expected... charge at full!
Most of the above means i have time on my hands most mornings...
My house is pretty much like the zappi diagram attached with the CT going to the podpoint but there is the CT going to the Solic200 water heater.

Errr ca t attach a photo... will edit soon...

 

Wanted to keep the build as simple as possible, independent of any current sensing. I have an OWL Intuition monitor which gives me a good indication of when I'm exporting to the grid, which is when I want to be charging. After a little trial and error, I've got a nice balance, and most of the time I can charge for free. I didn't set the threshold too high as I didn't want it switching on and off every few seconds with a slight variation in sunlight. The level I've got now is similar to a buffer zone between bright and hazy sunshine.
I just check the weather forecast for the following day, plug it in, and leave it to do it's stuff. If there is no sun forecast and I need a charge I will either use the Pod Point if I'm in a hurry, or use the trickle charger if I'm not and recoup some money from the solar. Every little helps.