low charging rate

[Deleted member 2439]

4.2 was the average for the last 200 miles or so whilst using some of Mark H techniques to achieve a better miles/kW. I won't be driving that efficiently now the temperature has dropped. My overall average from new is 3.9 over 1800 miles.

3.9 is pretty good IMHO ?

 

[Mark Holmes]

4.2 was the average for the last 200 miles or so whilst using some of Mark H techniques to achieve a better miles/kW. I won't be driving that efficiently now the temperature has dropped. My overall average from new is 3.9 over 1800 miles.

Don’t blame you me neither....roll on the warmer weather. ?

 

[Kithmo]

Hi, my point is being missed.

Tesco’s charger are 7kW chargers, not 7kWh chargers.
A kW is not the same thing as a kWh. That is the point I’m making, which, from an engineering or energy perspective is a key distinction.
A kW is a unit of power, a kWh is a unit of energy. I agree with the numerical aspect of your comments, but disagree with the units being quoted - for the reasons explained.

It’s a simple and innocent enough error, but on an EV forum we need to be getting these things correct - it’s the sort of error akin to people talking about their broadband speeds in MegaBytes per second - WRONG, it’s megabits per second.
My motivation here is not to tease, simply to point out that electrical engineering terms are being incorrectly applied.

Cheers - Rob

I still don't see the point you're making, the charger puts 7 kW of power out, so for every hour I'm connected I get 7 kWh of energy, so what's the difference between calling it a 7kW and a 7 kWh charger ?

 

[Deleted member 2439]

The power output of 7kW will only be an energy output of 7kWh if used for EXACTLY an hour, not 59m 59s, or 1h 0m 4s. These are engineering terms and as such should be applied correctly. If you are happy to continue using the terms incorrectly then that‘s fine - I’m simply pointing out an innocent error - which is analogous to saying that “I was driving at a speed of 60 miles”, when of course the speed would be 60 mph. I suppose it’s natural that such terms will become confused as they move from special use into everyday parlance. Exactly the same issue applies in the world of solar PV - with constant mixups of these same terms. Don’t take my word for it - there’s plenty of reference material out there:

kW and kWh Explained - Understand & Convert Between Power and Energy

 

[Kithmo]

The power output of 7kW will only be an energy output of 7kWh if used for EXACTLY an hour, not 59m 59s, or 1h 0m 4s. These are engineering terms and as such should be applied correctly. If you are happy to continue using the terms incorrectly then that‘s fine - I’m simply pointing out an innocent error - which is analogous to saying that “I was driving at a speed of 60 miles”, when of course the speed would be 60 mph. I suppose it’s natural that such terms will become confused as they move from special use into everyday parlance. Exactly the same issue applies in the world of solar PV - with constant mixups of these same terms. Don’t take my word for it - there’s plenty of reference material out there:

kW and kWh Explained - Understand & Convert Between Power and Energy

Having slept on it, the penny has finally dropped. Can I call it a 7kWh/h charger then

 

[Deleted member 2439]

Having slept on it, the penny has finally dropped. Can I call it a 7kWh/h charger then

View attachment 974

Hi,

Of course - however, you will see that the h above and below the line actually cancel each other out - leaving kW ! ?

The analogy with speed, distance & time is a good one - have a ponder on that. Speed = power (kW), Distance = energy (kWh), time is the same in both analogies.

All the best - Rob

 

[Taliano2]

Hi, my ZS EV is 6 months old and I have done 15000 miles already, ( I am a minicab driver)and I did my first service on 29/12/2020. My car have fill updates done during this time, 3 applied during the service day.My car reach 100% on a 7kw charger,but on the GOM ( range display) only shows 154 miles, don't give 163 miles as when is new, when turning the weather on, go to 132 miles range with full charge.
Fill day a go, I used CCS rapid charge and my car stay connected for 37 minutes, and the battery only charge 3.6 kwh with temperature of 3 degrees, the battery was 25%,the after 37 minutes, whent to 34%. Next day, I charge on an 7kw and the car get fully charged in 5 hours.