[Skirkby]

Hi all

I have an e-Niro and the UVO app. I also have a home wall charger - but the wall charger is not smart (6 years old) and doesn’t have an app in itself to tell me how much electricity was used to charge the car (or how much it cost).

Is there a way on UVO or on the car itself to figure out how much each charge cost (or how much electricity was consumed to charge the car)?

Thanks

 

[KiwiME]

You'll need a fancier charger to do that reasonably accurately.

 

[prawlin]

Maybe you could take your house electricity meter reads before and after the charge cycle, then deduct what you think the rest of the house has consumed? it’s likely the car consumed the lions share especially if overnight (providing you don’t have electric night storage heating or similar heavy consumer). Ok so it’s not ideal, but It might give you the information you need?

Peter

 

[wizziwig]

Could also get an OBD2 dongle + app and look at before/after change in reported CEC value. This won't include charging losses (up to ~12% depending on AC charging rate, home wiring, etc.) but will get you in the ballpark.

 

[championc]

Surprising that there's no "charging history" screen

 

[Skirkby]

Thanks everyone. Looks like I will need to upgrade my charger to a smart one.

 

[Skirkby]

Surprising that there's no "charging history" screen

I have had two Outlander PHEVs previously and they had this capability (cost per charge based on a price per Kwh you input). Not great, but at least it gave an idea.......as you say, surprised there isn’t an equivalent on the car or on the UVO app.

 

[Gary J]

Thanks everyone. Looks like I will need to upgrade my charger to a smart one.

Or... you could buy the Ohme cable. This will replace your normal charging lead and you can get charging stats from the accompanying app. It will even charge your car at times when electricity is the cheapest if you have a time of use tariff like Octopus Agile.

 

[burnt_crisps2]

Or... you could buy the Ohme cable. This will replace your normal charging lead and you can get charging stats from the accompanying app. It will even charge your car at times when electricity is the cheapest if you have a time of use tariff like Octopus Agile.

Better still, if switching to Octopus, then it’s on offer from them too...

Octopus Energy

octopus.energy

and use someone’s code to get £50 off your bill too when you switch.

 

[JohanGM]

Not sure how the electric system works in your place, but over here you could add a kWh meter to the specific group in your fuse box that feeds the charger.

Like this:

 

[jgwozdzicki]

@JohanGM, that’s a very cool idea! @Skirkby, I’ve been trying to figure out the same. The Zappi gets installed next week so that I think tracks charge but in the meantime I’ve been trying my best to track it via the 3 pin but eventually gave up!

 

[rosinchard]

Something like this, monitoring the cable to your charger? Not sure how accurate they are

geo Minim Energy Monitor - Self-Installed

geo Minim Energy Monitor - Self-Installed - CT Clip Sensor for Single Phase Electricity Meters: Amazon.co.uk: DIY & Tools

Shop geo Minim Energy Monitor - Self-Installed - CT Clip Sensor for Single Phase Electricity Meters. Free delivery on eligible orders of £20 or more.

www.amazon.co.uk

 

[ZoeTal]

I put a meter that was on the mains to the house onto the charge point and use that to monitor the amount of energy we use to charge the cars. If I calculate the amount of energy that the battery has taken based on the change in the percentage charge in the battery and then look at the meter, I get a considerable difference.
Here's an example of some of the data I get:

Car battery % at Start	Car battery % at End	% Change	kW from % battery (assumes 64kWh)	kW from Meter	Change in Mileage
42%​	79%​	37%​	23.68​	28​	105
21%​	60%​	39%​	24.96​	28​	106
33%​	71%​	38%​	24.32​	28​	109
31%​	69%​	38%​	24.32​	28​	111
62%​	98%​	36%​	23.04​	28​	105
41%​	79%​	38%​	24.32​	29​	107
40%​	75%​	35%​	22.4​	27​	101
46%​	82%​	36%​	23.04​	28​	108
48%​	84%​	36%​	23.04​	28​	106

The charging is normally done at night on the 4 hour Octopus Go window hence the fairly constant readings from the meter each time.
The discrepancy is nothing like as big when charging a Zoe 40.
The charge point is a Chargemaster unit and I also found big differences between what that gave (when it was working!) and what the car would report.

 

[KCross]

The state of charge percentages in most EV's is not linear, so you cant accurately calculate km's or kWh's from the change in SoC percentage.

 

[DangerousDoug]

I would second the suggestion of buying an Ohme cable. In fact, if you switch to Octopus Energy for your electricity supply, they had an offer which may still be active, supplying an Ohme charger for HALF PRICE (£200). You'll EASILY recoup this amount in electricity costs over the coming year, if you have a mid-sized house and EV charging, so to me it's a no-brainer. The Ohme charger integrates with Octopus Agile tarrif, charging the car only during the very cheapest half-hour slots. The charger can be ordered with a Commando 32A socket, or a Type2 socket, so it can be directly plugged into your existing charger - no electrical work needed . Just in case you're not yet on Octopus energy, my discount code (you and I both get £50 bonus) is:

Octopus Energy

Fair prices forever and greener energy from the UK's largest investor in solar generation. Save hundreds of pounds a year with Octopus Energy compared to the average Big 6 energy tariff.

share.octopus.energy

 

[Steven4]

The free Car Scanner Elm Obd2 app displays the "Cumulative energy charged" in kWh ever since the car left factory. Very useful tool, however I am not sure if it includes charging and conversion losses.

App also shows "Cumulative energy discharged" in kWh.

 

[ZoeTal]

Thanks Steven4 for the tip about the "Cumulative Energy" in Car Scanner. I hadn't spotted that so last night, I did the usual 4 hour charge and got the following:
Battery at start: 38% Battery at end: 71%
kW from battery %: 24.32 (assumes 64kWh battery)
Change in Cumulative Energy Charged: 25.5kWh
Energy used based on electric meter: 28 (This only has the charge point connected to it.)
So, it looks like the charging losses are around the 10% mark which I think is about right on a 7kW charger from what I have seen elsewhere.
Finally, the car is averaging 4.2miles/kW which means 25.5kWh would add 107 miles to the range.
I wonder if the charging loss changes based on the SOC of the battery..

 

[wizziwig]

There are also some very small losses in home wiring that won't show up on your EVSE. Bjorn did a video recently talking about charging losses using various methods and speeds on his Model 3. Same concepts apply to any EV. DC losses will likely be much lower on other cars since they have less aggressive battery conditioning and slower charging speeds.

 

[KiwiME]

kW from battery %: 24.32 (assumes 64kWh battery)
Change in Cumulative Energy Charged: 25.5kWh
Energy used based on electric meter: 28 ...
So, it looks like the charging losses are around the 10% mark which I think is about right on a 7kW charger from what I have seen elsewhere.

The CEC numbers are going to be more accurate than the SoC percent of an assumed battery capacity. However, the available energy from that CEC delta needs to be factored by the battery efficiency which I've measured at 96%. Also, aside from conversion efficiency AC energy needs to account for charging the 12V battery and supporting the electronics.

I wonder if the charging loss changes based on the SOC of the battery.

I don't see why it would. Hyundai tell us that the OBC efficiency is 91%, pretty sure it's the same unit as on the Niro.

 

[ZoeTal]

Thanks KiwiME.

If you have time, do you have a pointer to where I can understand what the 'battery efficiency' value is?