[A900ss]

I have a Rolec Smart charger and I’m on Octopus Agile but only found out today that the Smart charger does take in Octopus Agile 1/2 hour pricing every day. So in theory, you wouldn’t need an Ohme cable to maximise the tariff.

I’ve always used my charger in ‘dumb’ mode and relied on the car timers to ensure I get the lower rates on Agile.

I’ll test the charger to ensure it does actually turn on and off with the best rates over the next few days but I’m wondering if others are already using a Rolec on Agile and how well it manages the changing rates.

Thanks

 

[dk6780]

Really? They have kept that under a bushel, as have their app suppliers ev.energy! The latter are very vague and whose website contains statements such as "automatically optimize charging to take advantage of off-peak rates" not implying whether this is just using off-peak hours where possible (say for Octopus Go or Economy 7), or whether it goes the full hog and will select the exact best combination of individual half-hours turning on and off potentially many times as required for Octopus Agile.
Is there an API with your Ioniq that they can access to know how much charge your car requires, or do you potentially have to change it every night to say how much charge you want by when? Also, can it cope with Agile and pre-heating (the Ohme struggles as it really needs to turn back on at the pre-heating time to maintain the level of charge required whereas at present you have to request an artificially higher figure to allow for the use from the battery and the associated losses)?

 

[A900ss]

I know. I got the E-Mail response from EV Energy.

I’ll try it out tonight but my car does not have an app that Agile/Rolec can log into. It will have to rely on what the car tells it.

Let’s see how it goes but it will save me getting an Ohme cable if it works ok.

The Rolec smart charger worked fine on Go (charging at the 4 hours off peak) and then would always switch back on to pre heat the car as I had programmed the car so I expect that to work fine with Agile as well.

 

[dk6780]

The car will tell it nothing other than it will not take a charge either because it is full or the timer says No. I fail to understand how it can optimize Agile and achieve any percentage other than that when the car stops it (generally only when full apart from a few exceptions - is the Ioniq one?) unless it can calculate how long the car will take to charge - e.g. by subtracting the desired amount of charge from the initial charge. Is it expecting you to tell it each night when you plug it in? Then it risks the car being overcharged (if it charges faster than it expects) or vice-versa say when the weather is cold. The same applies to Ohme for non-API equipped cars.

 

[A900ss]

Well it’s a positive start. I’ve said I need my car charged by 06:30 and the app says charging will start at 22:30.
Let’s see if it stops and starts to get the best rates.

 

[A900ss]

The car will tell it nothing other than it will not take a charge either because it is full or the timer says No. I fail to understand how it can optimize Agile and achieve any percentage other than that when the car stops it (generally only when full apart from a few exceptions - is the Ioniq one?) unless it can calculate how long the car will take to charge - e.g. by subtracting the desired amount of charge from the initial charge. Is it expecting you to tell it each night when you plug it in? Then it risks the car being overcharged (if it charges faster than it expects) or vice-versa say when the weather is cold. The same applies to Ohme for non-API equipped cars.

I don’t understand the full charging process but the car must tell it how long it will take to charge as it always delays it’s charge based upon how much charge is needed.

If it needs only an hour, it charges later. If it needs a full charge, it starts earlier.
Like I said, I don’t understand the charging process but the charger does seem to know how long the car needs to be charged for.

 

[dk6780]

If I understand it correctly, the Ohme unit would assume that your car had no charge remaining and hence that you needed the full amount up to whatever limit you set. So if you set 100%, the full 28 kWh (or whatever the actual capacity of the Ioniq is).
It looks good that the car is going to start at 10:30 - clearly it doesn't require the full 8 hours to charge your car.
How much charge do you need, and is there any time required for battery balancing as would say be the case with a LEAF at 100%.
Looking at your data it is interesting that the lowest cost is at 10:30 itself!

 

[Woodulike]

Myenergi have always said there's no data coming from the car when it's plugged in on AC so the only way they can make the Zappi work with Agile is for the user to input how much charge they want added and by what time. I assume the other chargers need the same input so it will be interesting to hear how the Rolec works for you.

 

[A900ss]

Well based on what you both said about the charger not knowing how much charge to give, I slightly changed the parameters. I set the EV app to only charge on cheap rate charge and below 5p/kwh.

it looks like it did that and turned the charging on and off. I only needed a part charge so I could work out how many 1/2 hours of Agile I’d need and based my max cost per KWh on this.

I can be more daring at the weekend when I don’t need my car and trial it with no max cost per kwh and see what it does.

 

[dk6780]

Thanks for posting that and explaining the change in your plan, I can fully understand the desire to reduce the risk. What I can't understand is the usage at the later times? If the rates shown relate to the usage the lowest costs are

1. 10:30 4.69
2. 12:00 4.77
3. 3:30 5.29
4. 11:30 5.73

Yet usage was at about 10:30, 3:30 and 4:30 ish. The average is shown as 4.61 so either one is with VAT and the other without, or the figures are unrelated.

 

[A900ss]

I think it is a bit dumb after all.

I’ve been playing around with the times and taking the ‘only charge on cheap rate’ off and I’ve worked out it wants to allow 6 hours to charge my car (Ioniq 28). Other cars, if I play with the app are Leaf 30 (6 hours), Leaf 40 (7 hours), Ioniq 38 (7 hours). So it’s working on about 5 to 6 kWhs per hour being given to the car and also assuming a full charge is needed.

if you ask it to have your car ready in later than those hours (ie longer than 6 hours for my Ioniq) it then tries to start the charge at the cheapest single half hour time.
For example, I’ve told it I need my car at 9.30 tomorrow morning and it is has scheduled itself to start at 0:00. This is the cheapest single 1/2 hour slot this evening in Agile for me. However if it was smarter (and used the same 6 hour fill up window) it would start at 23:00 and then stop for the 1:00 and 3:00 1/2 hour windows as they are more expensive.

My guess is that it will start at 0:00 and just keep charging until fully charged.

I’ll test it tonight with no maximum pence per kWh, I’ll just let it do it’s thing and see what it does.

I’ll be asking for car ready at 9.30am and it’s circa 25% charged at the moment (so won’t need anywhere near 6 hours, more like 3 and a half).
Tonight’s half hour rates are below.

 

[A900ss]

I think it is a bit dumb after all.

I’ve been playing around with the times and taking the ‘only charge on cheap rate’ off and I’ve worked out it wants to allow 6 hours to charge my car (Ioniq 28). Other cars, if I play with the app are Leaf 30 (6 hours), Leaf 40 (7 hours), Ioniq 38 (7 hours). So it’s working on about 5 to 6 kWhs per hour being given to the car and also assuming a full charge is needed.

if you ask it to have your car ready in later than those hours (ie longer than 6 hours for my Ioniq) it then tries to start the charge at the cheapest single half hour time.
For example, I’ve told it I need my car at 9.30 tomorrow morning and it is has scheduled itself to start at 0:00. This is the cheapest single 1/2 hour slot this evening in Agile for me. However if it was smarter (and used the same 6 hour fill up window) it would start at 23:00 and then stop for the 1:00 and 2:00 1/2 hour windows as they are more expensive. I’ve marked in red the cheapest 12 1/2 hour slots (to make up the 6 hours the app thinks it needs to charge my car).

My guess is that it will start at 0:00 and just keep charging until fully charged.

I’ll test it tonight with no maximum pence per kWh, I’ll just let it do it’s thing and see what it does.

I’ll be asking for car ready at 9.30am and it’s circa 25% charged at the moment (so won’t need anywhere near 6 hours, more like 3 and a half).
Tonight’s half hour rates are below with a red mark next to the 12 cheapest 1/2 hour slots.
View attachment 128400 View attachment 128400

 

[A900ss]

Just a quick note to my test above. My Ioniq will NEVER need 6 hours to charge so I’m going to change my car in the settings of the EV app to a 60ah BMW i3 as the app thinks that takes 4.5 hours to charge. Still more than I would need even from zero % and hopefully it will help the app choose from fewer 1/2 time slots if it really does stop and start.

 

[kcrane]

@A900ss - Thanks for doing this research, following with interest

 

[A900ss]

Well if the Rolec EV app is bringing in Agile pricing, I don’t think the Smart charger is actually using them to get the lowest price charge.
Charging profile from last night below and I can’t spot the system it could be using.
Welcome to hear comments.

 

[Lexden]

I confess that I am confused. The Agile tariff is regional as are all tariffs. To download the Agile forward prices, someone needs your API key. For example, I use the OEW App and to get accurate usage and costs, I have to enter my API key and tariff information. I believe that the Ohme cable has a built in sim card to extract the required information from Octopus. How is the Rolec App getting accurate price information?

From an installer Site (Ohme Wallbox):

• Already linked with electricity providers such as Octopus.
• Just plug in and charge at the cheapest rate.
• The cheapest smart tethered chargepoint on the market.
• Very small, neat and compact.
• Optimise for green energy and battery life.
• Set charge schedules including: Only charge when electricity price is below £ x.
• Charge when electricity generation is at its ‘greenest’.
• Built in pre-paid sim card so always connected.

It is not clear whether the Wallbox uses an API or GeoLocation to get prices. If it is the latter then I suppose the same is possible via an App. Every day is a school day.

 

[A900ss]

It Geo Locates. That’s why you have to put your location into the EV App. The people at EV have confirmed that they get the 1/2 hourly prices everyday for Agile.

 

[dk6780]

Interesting that it took a break after the first half hour. Please can you post the forward pricing as I can't access the previous file that you posted yesterday.

 

[A900ss]

Interesting that it took a break after the first half hour. Please can you post the forward pricing as I can't access the previous file that you posted yesterday.

These are the prices for this morning. I’ve marked the cheapest 12 (6 hours to charge an Ioniq according to EV App).

 

[Paul Hopwood]

Re Ohme Box. You select your supplier and input your postcode in the Ohme app to get the correct tariff (which I presume communicates with the Ohme box and / or Ohme HO).
"Your home postcode will help us select the correct electricity tariff to maximise your savings".
My assumption would be that the app communicates with a central server which communicates with the SIM card in your Ohme box. I have no idea tho tbh.