More expensive to drip charge via a 3 pin plug at approx 2kw than using a pod point for example at 7kw?

[LewChappers]

Does anybody know if it is more expensive to drip charge via a 3 pin plug at approx 2kw than using a pod point for example at 7kw. Obviously I am aware the 3 pin is slower, but in regards to cost what works out more ??

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[daveo4EV]

charge rate (speed) rarely affect billing rate

you are trying to fill a bath tub (your battery)
your bath tub holds 83.4 gallons of water
you pay for the water based on the units of "gallons" you use
you do not pay based on how "fast" you fill the tub.

you are typically billed by the kilo-watt-hour (kWh) - not the rate (kW) that you fill the battery.

the battery hold's the same number of kWh's - regardless of how fast (kW) you fill the battery

any variance in billing rate is likely due different levels of efficiencies due to slightly different electrical overhead at different charge rates, but typically these are statistically insignificant.

your Taycan battery holds 83.4 kwh's - if you are paying by the kWh it doesn't matter how fast/slow it takes to provide the 83.4 kWh's.

 

[W1NGE]

Does anybody know if it is more expensive to drip charge via a 3 pin plug at approx 2kw than using a pod point for example at 7kw. Obviously I am aware the 3 pin is slower, but in regards to cost what works out more ??

It will be the same - standard daily standing charge for your electrical supply plus the kWh charge (36p or so). You are not charged on how much you can use at once but how much you use per kWh.

 

[f1eng]

Does anybody know if it is more expensive to drip charge via a 3 pin plug at approx 2kw than using a pod point for example at 7kw. Obviously I am aware the 3 pin is slower, but in regards to cost what works out more ??

Depends only on the cost per kWh of your contract.
If you have one of those EV contracts giving cheap units in the middle of the night a 7kW unit will reduce the time it takes to charge the car cheaply by charging more during the cheap period.

 

[LewChappers]

To give you an idea our electric cost per day is £7. With the car charged in using a 3pin plug from midnight till midnight(so a full day), these codes rise to £28. So that’s an extra £21 for one day and the charge is minimal.

 

[JAGMAN]

I have noticed very high billing with slow charging. My theory is that there is so much overhead consumption that very little battery charging occurs.

I recently moved into a new house and am awaiting a fast charge installation. My electric bills are far higher as I charge at 120v and 1600 watts. I think the water pumps and other auxiliary systems that run during charging are consuming as much power as charging. On average it take 4 days to charge from 35 to 80%.

 

[W1NGE]

I have noticed very high billing with slow charging. My theory is that there is so much overhead consumption that very little battery charging occurs.

I recently moved into a new house and am awaiting a fast charge installation. My electric bills are far higher as I charge at 120v and 1600 watts. I think the water pumps and other auxiliary systems that run during charging are consuming as much power as charging. On average it take 4 days to charge from 35 to 80%.

Do you have variable charge rates for electricity depending on the time of day?

 

[f1eng]

I will check when I get home but I was surprised to see, when I checked it out before holiday, that with the 13A plug charger the screen on the Taycan showed charging at 2.2 kW, I has expected more, so I tried the one from the Toyota PHEV and it showed the same.
The Toyota has no charging display but measuring its consumption whilst charging the Toyota gave 2.6kW.
I will try measuring input and output when I get home next Sunday, I have the kit.
Maybe there is a 400w overhead.

I did notice on our 7kW charger the reported consumption of the charger was 7.2 kW but the car reported 6.6 kW charging, so there could be an overhead of 600W there too so both quite lossy IMO.
It works out between 10% (7kW charger) and 20% (13A plug) of the power fed to the car is not charging the battery but presumably being used for something else.

It seems high I will check a bit more once I get home but anyway on that basis the 13A plug solution is more expensive than a 7kW charger due to higher losses over the charging period.

I had not expected this much.

 

[W1NGE]

I will check when I get home but I was surprised to see, when I checked it out before holiday, that with the 13A plug charger the screen on the Taycan showed charging at 2.2 kW, I has expected more, so I tried the one from the Toyota PHEV and it showed the same.
The Toyota has no charging display but measuring its consumption whilst charging the Toyota gave 2.6kW.
I will try measuring input and output when I get home next Sunday, I have the kit.
Maybe there is a 400w overhead.

I did notice on our 7kW charger the reported consumption of the charger was 7.2 kW but the car reported 6.6 kW charging, so there could be an overhead of 600W there too so both quite lossy IMO.
It works out between 10% (7kW charger) and 20% (13A plug) of the power fed to the car is not charging the battery but presumably being used for something else.

It seems high I will check a bit more once I get home but anyway on that basis the 13A plug solution is more expensive than a 7kW charger due to higher losses over the charging period.

I had not expected this much.

Cabling could be restricting.

 

[Gnasher]

I will check when I get home but I was surprised to see, when I checked it out before holiday, that with the 13A plug charger the screen on the Taycan showed charging at 2.2 kW, I has expected more, so I tried the one from the Toyota PHEV and it showed the same.
The Toyota has no charging display but measuring its consumption whilst charging the Toyota gave 2.6kW.
I will try measuring input and output when I get home next Sunday, I have the kit.
Maybe there is a 400w overhead.

I did notice on our 7kW charger the reported consumption of the charger was 7.2 kW but the car reported 6.6 kW charging, so there could be an overhead of 600W there too so both quite lossy IMO.
It works out between 10% (7kW charger) and 20% (13A plug) of the power fed to the car is not charging the battery but presumably being used for something else.

It seems high I will check a bit more once I get home but anyway on that basis the 13A plug solution is more expensive than a 7kW charger due to higher losses over the charging period.

I had not expected this much.

Same.

I get 2.2kw from a granny plug so around 6 miles of charge per hour.

However, i have a fixed tariff at 16.8p per Kwh so it’s cheap (But slow!)

We had Surecharge lamppost chargers put in with the council which were 7kw and at 28p but they have shot up to 48p + 35p connection overnight which is more expensive than the Shell and IONITY options so won’t bother with those now and hope they go out of business at those prices !

 

[f1eng]

Cabling could be restricting.

It would be getting a bit hot if the resistance was enough to dissipate 400W, and it isn’t.
The cable for the 7kW charger does get warm, but not hot enough to explain 600W cable loss.
More likely to be something the car itself is using for “housekeeping”

I will do more checks when I get home but Ionity fast charge may end up being cheaper than home charging soon.

I an a bit disappointed to have missed out on cheap charging at home with the Taycan

 

[Gnasher]

It would be getting a bit hot if the resistance was enough to dissipate 400W, and it isn’t.
The cable for the 7kW charger does get warm, but not hot enough to explain 600W cable loss.
More likely to be something the car itself is using for “housekeeping”

I will do more checks when I get home but Ionity fast charge may end up being cheaper than home charging soon.

I an a bit disappointed to have missed out on cheap charging at home with the Taycan

I thinkif you got Solar you would luck in.
Friend of mine has this for his Tesla and calculated a 4 year pay back. On octopus tarrif so even charges the solar batteries overnight at 7.5p !

 

[f1eng]

I thinkif you got Solar you would luck in.
Friend of mine has this for his Tesla and calculated a 4 year pay back. On octopus tarrif so even charges the solar batteries overnight at 7.5p !

I have solar panels but they mainly run the house and hot water, if there is surplus it would help charge.
My solar system paid for itself in around 7 years just doing that.

 

[daveo4EV]

It would be getting a bit hot if the resistance was enough to dissipate 400W, and it isn’t.
The cable for the 7kW charger does get warm, but not hot enough to explain 600W cable loss.
More likely to be something the car itself is using for “housekeeping”

I will do more checks when I get home but Ionity fast charge may end up being cheaper than home charging soon.

I an a bit disappointed to have missed out on cheap charging at home with the Taycan

there are resistance losses and heat losses but mostly the "loss" from what I've been told is the overhead of AC/DC conversion inside the vehicle and the power losses from have the vehicle's systems "alive" and running any thermal conditioning system during the charging process…my Tesla's, Bolt, Taycan, Cayenne can all be "heard" to run thermal conditioning systems during the charging process depending on ambient conditions, battery temperature, and length of charging session and speed (kW) of the charging session - any power used to heat/cool the battery during the charging session is "lost" power and will show up in "overhead" in the charging session

a good solid 3-8 hour charging session with my Taycan in winter can raise the ambient temperature of my garage 2-6F vs normal - and after about an hour or so of charging you can visit the garage and hear and feel the waste heat being expelled in the front wheel wells…all this heat is power that did not land in the battery - and you can feel it i the garage temperature - and the kWh's on your meter.

i.e. why did it take 24 kWh to add 22 kWh to my battery? the answer is typically AC/DC conversion losses, and power overhead the car used unrelated to battery charging during the session - the car is "more awake" when charging than when sitting there doing nothing - so more power is used by just having certain systems "alive" during the charging session.

 

[daveo4EV]

Depends only on the cost per kWh of your contract.
If you have one of those EV contracts giving cheap units in the middle of the night a 7kW unit will reduce the time it takes to charge the car cheaply by charging more during the cheap period.

this is an excellent point - it could cost more to charge at slower rates if you have variable tarriff's during the charging session - in Northern California I have an 8 hour window every night (11 pm to 7 am) where my power is "cheaper" than other hours - it's best to "fit" my charging into that window to minimize electrical costs...

but the tariff is still "per kWh" - not based on draw-rate (kW) - and the number of kWh's is still a "bath tub" - so I'm charged on the number of kWh's I'm stuffing into the battery - but across any given charging session the cost of a single kWh can vary due to different tariff's at different times of day.

since I've been driving from 2011 charging at home seems to ahve a 5-10% overhead vs. kWh's I've shoved into the battery - if you "add" 10 kWh to a battery it seems to take 10.5-11.2 kwh of "billed" kWh's - this has been pretty consistent across all the EV's i've owned (and my friends confirm similar experience for their EV's).

you can rule-of-thumb charging overhead at about worse case 10% and you'll be right more often than not - i.e. adding 80 kWh of power to your Taycan will result in about 85-86 kwh of "meter" billings on your electrical bill that month - I'd love any data from outside North America if anyone has experience in this space.

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