How efficient is your charger?

[Waterstoney]

Here is brief (updated) result first for ZS LR:
MG UK 3 ping charger (10A) efficiency:
Average 86.5% cold 77% max 90%

In a simple way, 1 kWh power consumption adds 3.8 miles （5.40 km) range with normal drive mode

5kW Char.Gy:
91%
1kWh: adds 3.0 miles (4.83 km)

7kw Podpoint at Tesco:
89%

50kW ESB CCS
90%

Added based on feed back from other members on this thread.
aserratic PodPoint
3.2kW/3.6kW=89%

GaryMG4 Tesla Super Charger
126kW/134kW=94%

More story
Recently got my MG ZS LR. I use normal drive mode with KERS 3. I am trying to found out which is the most efficient charger.

I use original MG ZS UK 3 pin charger. I have not install a fast charger yet.

I use TPLink Energy Monitor to check power consumption. I use iSmart to check power received by my ZS.
Efficiency starts with 77% when battery is cold. It reaches to 88% after 30minuts. Average efficiency is about 86.5%.

For simple way, to read normal drive mode remaining range at start and at end of charging. Then the result is divided by power consumpted. Short charging is less efficient because the battery is cold.

My conclusion is unfair to char.gy because I do not want to pay them double rate comparing with my home electricity rate. I want to see your home charger efficiency before I buying.

 

[aserraric]

I think your are confusing your wallbox/ICCB with the charger.

When you do AC charging (using only the top part of the connector on the car), the charger sits in your car. The box on either your wall or in the cable doesn't do anything but control the current and check for faults. All the conversion from AC to DC happens in the car itself.
The difference between the energy measured outside the car and in iSmart is simply the energy that is consumed by the car itself before it gets to the battery.
There will not really be a difference in efficiency no matter where you are plugged in. However, since the losses are more or less constant, you want to charge at the highest power available (for the LR, that is 11kW or 3x16A), since it will take less time (and therefore fewer losses per kWh).

Only when you use DC charging (using the bottom part of the connector as well), the charger is the giant box that sits on the curb and that may have an influence on efficiency.

 

[Waterstoney]

Hi aserraric,

Thanks for the clear detailed clarification.

So the wall box is just some kind of energy monitor plus safety/management feature. It does not matter much to have different brand.

I only run 1050miles in 3 month. 319.0kWh electricity was used. That gives me 3.29mls/kWh including charging loss and some heater/aircon usage. Charge time is not a problem to me.

I am pretty happy with "granny" charger. It could be more effient to charge slowly unless someone with a proper wall charger do better with efficiency.

 

[aserraric]

Well, as I said, while AC charging, faster is generally more efficient. The car uses a certain amount of power just for being on and running the charger, no matter how fast you charge. I don't know off-hand how much it is, but let's say it's 250 W.

If you charge at 3 kW for an hour, you consume 3 kWh from the grid. But since your car has consumed 250 Wh during that time, the battery only receives 2.75 kWh.

However, if you charge at 6 kW for half an hour, you still consume 3 kWh from the grid, but your car only consumes 125 Wh, so your battery receives 2.875 kWh.

 

[Bodgerx]

Well, as I said, while AC charging, faster is generally more efficient.

I'm not sure what you mean by that, but AC granny charging is going to give you less efficiency (more charging losses) than your home wall charger.

 

[aserraric]

A "granny charger" (I prefer the term ICCB) is going to give you single phase between 6 and 16A, depending on the specific device and cable.

A wall box (again depending on the device and wiring) will give you anything between single phase 6A and three phase 32A.

So you can theoretically dial a wall box down to be slower than am ICCB, but in general, yes, a wall box will be faster and therefore more efficient.

Again, more power means faster charging, which means shorter charging time, which mean fewer losses over time, which means better efficiency.

ETA: Both an ICCB and a wall box are examples of AC charging. Practically nobody has a DC charger at home, those cost upward of 20k.

 

[Bodgerx]

I was more thinking most of the loss in granny charger (Vs dedicated wall charger) is down the thinner, longer, lower spec cable. I appreciate both methods are AC and both end up running through the car's onboard AC/DC charger.

Appreciate the ICCB term, but I think 'granny' has stuck for now and most people seem to know what it is Vs the proper term

 

[Waterstoney]

I like the InCableControlBox(ICCB) term.

I agree withe Bodgerx that long circuit would makes charger less efficient. When it was cold in March, I could measure temporature rise when charging. Car charge port was about 9°C higher than environment temperature (it was 10°C). ICCB was more than 10°C higher. My WiFi enabled energy monitor was 20°C warmer. Even the empty socket in the same room is several degrees warmer after several hours of EV charging.

MG ICCB is 10A Rated. It consume 2.4kWh ±2% power. Up to 2.09kWh went to battery according to iSmart.

Anyone has a reading of wallbox power consumption together with iSmart charging rate reading?

 

[aserraric]

I'm charging right now, and my wallbox reads 3.6kW, iSmart reads 3.2kW. This is with a 32A rated type 2 cable.

 

[Waterstoney]

Thanks aserraric for checking. so the efficiency is 3.2÷3.6=0.889=88.9%. It is about the same efficiency with ICCB. If you charge above 80%, it would always be a slow charging. Does your wall box support faster charging speed?

 

[aserraric]

If you charge above 80%, it would always be a slow charging.

On AC, the charging speed stays constant throughout the entire charge, it doesn't matter if you go past 80%. On DC, the charging speed drops drastically above 80% but is still faster than an ICCB.

My wallbox supports up to 11kW, unfortunately since my car is a SR model, it only charges single phase, so I'm limited to 3.6kW. For the full 6.6kW the car is capable of, I would need a 22kW wallbox (which my house wiring does not currently support).

 

[Waterstoney]

On AC, the charging speed stays constant throughout the entire charge, it doesn't matter if you go past 80%. On DC, the charging speed drops drastically above 80% but is still faster than an ICCB.

My wallbox supports up to 11kW, unfortunately since my car is a SR model, it only charges single phase, so I'm limited to 3.6kW. For the full 6.6kW the car is capable of, I would need a 22kW wallbox (which my house wiring does not currently support).

11 kW wallbox? Do you have 3 phase power supply? Single phase should be limited to 7.4 kW. I would expect a wallbox charges 3 times of speed a ICCB. In your case it is only 50% faster than my ICCB.
@aserraric: Have you dialed down charging power for prolonging life of battery?

Charging power rate should be the same whatever it is LR or SR.

Charging ZS SR with 7 kW wallbox should takes 8 hours from empty to full according to spec. That is 51.1kWh (49 usable) ÷ 8h = 6.39 kW (6.13).

For LR, it should takes 10.5 hour to charge according to spec. Charge speed is similar: 72.6 kWh (68.3 ) ÷ 10.5h = 6.91 kW (6.50).

 

[aserraric]

Yes, I have 3 phase power supply, but a 11kW wallbox can only deliver 3.6kW per phase (11/3=3.66).
To get 7.4kW on a single phase, you need a 22kW wallbox (which needs 3x32A wiring which I do not have). But I wouldn't get that anyway, since the car maxes out at 6.6kW.

So no, I haven't dialed down or limited anything. 3.6kW is simply the maximum speed a SR model can reach on a 11kW wallbox.

And no, the charging speed is not the same between SR and LR. SR is limited to 6.6kW single phase. LR can do 11kW three phase charging (although I had read somewhere that some newer LR models are also limited to 6.6kW single phase now).

Also, pet peeve of mine: kW is power (momentary), kWh is energy/capacity (1kWh = 1kW for an hour). People keep mixing those up, but they're not the same at all. A wallbox has a power rating, so it is a 11kW wallbox, not a 11kWh wallbox.

 

[Waterstoney]

T

Yes, I have 3 phase power supply, but a 11kW wallbox can only deliver 3.6kW per phase (11/3=3.66).
To get 7.4kW on a single phase, you need a 22kW wallbox (which needs 3x32A wiring which I do not have). But I wouldn't get that anyway, since the car maxes out at 6.6kW.

So no, I haven't dialed down or limited anything. 3.6kW is simply the maximum speed a SR model can reach on a 11kW wallbox.

And no, the charging speed is not the same between SR and LR. SR is limited to 6.6kW single phase. LR can do 11kW three phase charging (although I had read somewhere that some newer LR models are also limited to 6.6kW single phase now).

Also, pet peeve of mine: kW is power (momentary), kWh is energy/capacity (1kWh = 1kW for an hour). People keep mixing those up, but they're not the same at all. A wallbox has a power rating, so it is a 11kW wallbox, not a 11kWh wallbox.

Thanks for pointing out my mistake with unit of power. I updated the unit.

So only 6.6 kW is usable for single phase charging for ZS. I would need 20 kW charger for getting full 3 times the charging speed. Thanks for the tip.

Most UK household only have single phase. I would expect charger dealers advertising single phase charger unit for reducing price and cost.

 

[Gadget Geek]

Yes, I have 3 phase power supply, but a 11kW wallbox can only deliver 3.6kW per phase (11/3=3.66).
To get 7.4kW on a single phase, you need a 22kW wallbox (which needs 3x32A wiring which I do not have). But I wouldn't get that anyway, since the car maxes out at 6.6kW.

So no, I haven't dialed down or limited anything. 3.6kW is simply the maximum speed a SR model can reach on a 11kW wallbox.

And no, the charging speed is not the same between SR and LR. SR is limited to 6.6kW single phase. LR can do 11kW three phase charging (although I had read somewhere that some newer LR models are also limited to 6.6kW single phase now).

Also, pet peeve of mine: kW is power (momentary), kWh is energy/capacity (1kWh = 1kW for an hour). People keep mixing those up, but they're not the same at all. A wallbox has a power rating, so it is a 11kW wallbox, not a 11kWh wallbox.

I always use the analogy of a bucket. kWh is the capacity of the bucket, kW is how fast the water is pouring in.

 

[drmcw]

T

Thanks for pointing out my mistake with unit of power. I updated the unit.

So only 6.6 kW is usable for single phase charging for ZS. I would need 20 kW charger for getting full 3 times the charging speed. Thanks for the tip.

Most UK household only have single phase. I would expect charger dealers advertising single phase charger unit for reducing price and cost.

Look at aserraric's location; it's not the same as yours. In the UK the ZS doesn't support 3 phase charging, just single phase, but will charge at 7kW. If you get a single phase charger in the UK it will allow you to charge at these sort of speeds. It's well worth doing, in fact I'd go as far as to say that you should do it and the granny charger should be used only in an emergency.

 

[Waterstoney]

I am looking for 7kW untethered low profile charger in UK. Podpoint is my front runner on 11 June 2023.
- cost less: gbp890 include installing
- use 1.5w: cost gbp7 per year
- low profile

Here are some more details:
PodPoint solo 3 home gbp890 330x290x112 2.5w

EON gbp1029 460x315x135

Rolec Zura gbp1350 410x260x157 7.5w

QUBEV 330x200x132 10w

Hive gbp939 370x240x130

Wallbox from Halfords gbp1545 198x210x99

Is there any interesting features that I should have?

 

[Bodgerx]

I have the previous gen Podpoint Solo Home 2. 7kw.

Works well with both my previous Ioniq and current ZS.

Has WiFi and an app that shows charge history where you can configure your £/kWh rate (with timings) etc.

These things a pretty straightforward really. In fact if anything I'd like them to be simpler and have the car do the times charges and the fancy stuff. Dummer the better IMO.

 

[Waterstoney]

These things a pretty straightforward really. In fact if anything I'd like them to be simpler and have the car do the times charges and the fancy stuff. Dummer the better IMO.

@Bodgerx: I agree that the dummer the better. Dum charger wasting less energy.

I repeated charging my efficient test with char.gy in UK. 5kW char.gy is actuallt more efficient than 3 pin 2.4kW ICCB charger. 5.37kWh was consumed from char.gy in one hour. 4.94kW power was recieved by ZS LR according to iSmart. That was 92% efficiency on char.gy comparing with 89.6% on 3 pin ICCB charger. Removing 10m extention between TPLink energy monitor and ICCB charger improved efficiency by 3% comparing result in my prevous post.

- 5 kW charger could save GBP50 on efficiency for 12k miles comparing with 3 pin ICCB charger.

- 10W power consumption by wallbox costs GBP30 per year @34p/kWh. 0.5W
TPLink energy monitor only cost GBP1.5 per year.

- 7kW wallbox charges 3x faster than 3 pin ICCB. This is not an advantage to me only driving 4000 miles a year.

- Safty could be main concern of house electrical circuit. I am still to justify why I shall pay for wallbox cost of about GBP1000. I carried out some tests for more evidence to support purchasing.

* Voltage drop check with load.
8.5kW electric shower bring voltage down by 3v at consumer unit with 100A feed. It is about the same power as EV charging wallbox.

3kW kettle brings voltage down by 3 to 5v at socket depends on time. It bring 2v down at consumer unit. It is similar to 3 pin ICCB charger.

3kW kettle brings voltage down by 11v with 2 extentions with length of 12 meters. 6v voltage drop on 2 extentions sockets. I am surprised to find out that about 100W of heat is generated on electric wiring.

Charging ZS LR brings voltage down by 8v with two extention leads. 2nd extention is just for a spare socket for voltage measurement using multimetre.
I am not electrician. I feel it looks normal with the voltage drop: 2v for house power supply, 2v on wall socket, 4v on extention.

* Thermo checking is requied on all sockets in house they could be part of ring circuit.

I am using TPLink ernegy monitor as my smart power control. It consume 0.5W power. Temperature rises 10°C higher when it is not charging. Temperature of TPLink energy monitor rises 20°C higher when ICCB is charging at 10A.

Temperatue rises 10°C on socket when ICCB charger is used for hours. Sockets temperatue also rise 1 to 2 °C for those on circuit to consumer unit. Plug generates more heat than hard wiring.

I could not conclude that 3 pin ICCB charging is not good enough for normal charging. I feel wall box is marginal better. I would like to hear what you think.

 

[aserraric]

I wouldn't worry too much about power consumed by the wallbox. 10W of power usage there is negligible next to the approx. 400W power used by the car.

If I could charge at 7kW instead of 3.6kW, I absolutely would. However, I'm not willing to spend several thousand € to get my house wiring up to that, because that would take forever to recoup.