I would like to share with you the result I achieved in charging my EV (electric vehicles) with my solar panels, using Homey as a management box and Advanced Flows. This way of doing things allows you to save the purchase of a specific management device which usually costs between € 500.- and 1000.-, and which in most cases never pays for itself. The method presented here goes a little further than simply charging when there is enough sun, and stopping everything when there is not enough. The goal was to vary the charging amperage according to the available current. This Topic is an evolution of the Topic I had already written on the subject with Standard Flows. These flows work perfectly well and I have been charging two EVs only with my solar panels since late February 2022. Feel free to ask me any questions if something is not clear.
Hello are you sharing your flows in the way that I can import it via device capability? If yes I’m currently don’t have a clue where
I would appreciate any support. Thank u.
Regards Marco
Hello and thank you for your message.
I have to admit that I don’t know how to share an Advanced Flow, but if you do, I’d love to hear from you.
For a good understanding of how the flows work, I’d advise you to start from the beginning, using the images of my flows as a basis. You might even be able to improve or simplify them that way. As far as I’m concerned, they’ve been working perfectly well for a long time now, and I use them practically every day to charge two electric cars.
I don’t use the Night Charge flow any more because, since the beginning of 2023, the price of electricity at my place is now the same during the day and at night (before, it was cheaper at night…). So if there’s no sun, I use the Manual Charge whenever I want.
As for Calculation Flows, it’s not compulsory, but it does help to smooth out the excess electricity curve. The problem is that the Insight Trends averaging app is no longer available, having been replaced by another… which doesn’t work properly. So I’ve cobbled together a flow that does an average and works well. If you like, I can share the image with you here.
Finally, I’d like to point out that my flows don’t take into account the change from 1 to 3 phases, and vice-versa, although the Go-e Charger terminal does and so does the Homey app for the Go-e Charger. It would be enough to complete the Solar Charge Flows flow according to the same logic, but in fact I have no use for it because a maximum charge of 16A on one phase (3.7 kW) is enough for me. Changing phase takes time, and my solar installation isn’t powerful enough to supply enough excess power over a long period to make it worthwhile switching to 3 phases.
Great work. Thanks for sharing.
I have one question on the solar charge flow. In the flow where the different amperage is set, is the logic in the image correct? I have made that flow identical to yours, but I would like to reverse the true and false compared to your image. Or is there something I am missing?
Hello and thank you for your question.
I think it depends on how you did your maths (positive or negative result) as well as the value of your variables. Personally, in my calculation flow to determine excess power, I have a negative result when I have excess power to use to charge the car. For example, if my solar panels produce 4000W and my house uses 1000W, I’ve done my calculations to come up with a result of -3000W. That’s my own logic, and you can also have the opposite logic, i.e. arrive at a result of 3000W. In my solar charge flow, I didn’t enter the amperage values directly, but I did enter variables so that I could change them easily (which I never do, actually…). So for a Charge 6A, for example, I have a variable of -1400, for 7A a variable of -1600, and so on. If you’ve made your maths with positive results for excess electricity, it’s possible that the true and false outputs need to be inverted. In my opinion, this is why you could end up with the opposite solution. I hope I’ve been able to help you!
Hi and thank you for your question. I’ll try to answer it as best I can.
My Calculation Flows has two goals. Firstly, to smooth the solar power excess value, by averaging the last two minutes every 2 minutes, and then putting the result into a variable (in this case the Insight W I/E w/o EV variable). So every 2 minutes, this variable is updated. Then, in the Solar Charge Flows, the change of this variable is picked up at the beginning of the flow, which triggers or not the charge, respectively an adaptation of the charge amperage. I could have done all this in a single flow, but I preferred to separate the two. The second purpose of Calculation Flows - and this is a very important point - is to cancel the increase in house consumption when the charging station starts charging. Let’s take an example: if the solar power production is 3000W and the house consumption is 600W, there’s a surplus of 2400W that can be sent to the car. So the charging station will start charging at 10A (approx. 2300W), but the house consumption must not rise to 2900W (2300+600) because of the start of charging, otherwise charging will stop again immediately because Homey will think there’s only 100W left, whereas there’s still 2400W left. This element of the calculation is therefore very important, and perhaps also answers your second question.
If solar production and home consumption (excluding charging station) are stable, there’s no reason for the charging rate to change constantly. It will be re-evaluated every 2 minutes, but generally it rises gradually and then gradually falls again. If it continually yo-yo’s with a difference of several hundred watts, there’s a problem.
Don’t hesitate to ask me more questions. Personally, I’ve been using these flows almost every day for several years now. The calculations can certainly be done in a totally different way, but in a way, you still need to know how much energy is available and can be sent to the car. On the other hand, this value must have a certain stability. I wouldn’t want my charging station to potentially adjust its amperage every 5 seconds.
Hi! I am trying to do same thing here. There is one thing that my brains can´t solve. How to do the calculatinon of remaining power? I have set the limits with the amper but when charging goes on the limits are no loger valid?
Your calculation should look something like this: energy available to charge the vehicle = solar production - (home consumption - energy supplied by the charging station).
In your flow, I don’t understand why your Logic ‘Current usage’ card is not the same as the ‘KULUTUS KA’ card. In my own flow, it’s the same value, i.e. the result of the calculation. The problem I potentially see is that as soon as your vehicle starts charging, your ‘Current usage’ will increase by the amount of power charged, whereas the value should remain the same, otherwise it can’t work…
I think the goal is to drive the “current usage” to 0. (Use all the solar power available).
So not “the same”
Thats not a problem, its the goal!
If the current usage is negative (surplus of solar power), you increase the power charges with exactly that amount, driving the usage to 0.