I set my charger at 10A 2.3KW last night to charge my Tesla EV to 80%.

This morning the charger indicated it has taken 10.22Kwh but the car indicated up 8 kwh.

Does this mean I have lost 2 kwh? Should I try another charger?

I paid 2500B for this charger:

22 minutes ago, Thailand J said:

I set my charger at 10A 2.3KW last night to charge my Tesla EV to 80%.

This morning the charger indicated it has taken 10.22Kwh but the car indicated up 8 kwh.

Does this mean I have lost 2 kwh? Should I try another charger?

I paid 2500B for this charger:

That's apparently normal, as I paid attention one time, charging @ 7.4kWh

Car took about 38kWh

PEA meter stated about 44kWh used.

Charger being the only think on the grid, as house was on solar.

Sounds normal. Charging with a 7KW wall charger typically results in a charging efficiency of approx 90% give or take a few percent...that is, only approx 90% ending up in the battery. Why is this?

It's primarily because of the power efficiency loss in the EV "onboard charger (OBC)" where the AC power being fed to it from the external charger (an external charger is not really a charger but a safety device...a fancy switch/circuit breaker to assist/monitor the charging process).

Converting AC to DC power "in the OBC" is where most of power loss occurs and then some more in the cable between the external safety device and EV, also some heating in the battery, and cooling of the OBC with the EV's radiator fan motor. But the majority occurs in the EV's OBC as electronic AC to DC rectification process occurs. It's just like how your phone's USB charger can get very warm when charging your phone's battery as that charger converts AC voltage to a much lower DC voltage....that heating (power loss) is from the rectification and step-down of the higher AC voltage. This EV charging process adds up to around 10% loss in charging efficiency with a wall charger....you end up with around 90% (give or take a little). And with a "granny" charger that typically comes free with the EV and has a max charge rate of around 8 to 10amp or 2K the charging efficiency is only around 85%.

You are probably thinking with a 10% power loss then 10.22KW going in results an approx 1KW loss or 9KW reaching the battery so my EV should report it gained 9KW instead of 8KW. However, depending on how your EV "rounds and displays" the power gained/used combined with the accuracy of of the EV power measurement system could easily have resulted in an 8KW gain display.

You may have actually gained 8.99KW but if your EV power measurement system does not display "decimal point amounts" like 8.1, 8.9, etc) it would only show 8KW gained.

And remember the accuracy of measurement it not going to be more accurate than several percent which adds error to the power measurement gain/loss.. I wouldn't be surprised it you could have charged "just a little more"....like maybe 10.5KW going in then your EV display would have shown 9KW gained.

Yeap, charging efficiency, EV system rounding & display method, and accuracy of measurement (in the EV and wall charger) are all players in the measurement of the power gained/expended.

Edited 9 hours ago9 hr by Pib

Thanks for the above replies.

I will continue to use this charger at home over night.

Charging at Tesla super charger at Central Pattaya Beach took 20 minutes to top up from 20% to 80% but it can turn out to be super expensive. There are always sales some where in the mall. Last week I went out chrging my car but came home with a pair of new running shoes. Addidas IDAZERO EVO mark down from 5800B to 4080B, how can you resist?