Charging Wattage Difference

there are charging losses, but that is a big spread

 

The Toyota app is reporting what is going into the battery. The Chargepoint App is recording what is coming out of the wall. From the wall it is powering the charging circuitry (which includes converting the 240VAC to whatever DC is needed to charge the battery), running battery cooling fans (or powering battery heater, if needed), maintaining the charge of the 12v battery, and putting charge into the battery. That is why there is a difference.

 

I just installed the Toyota app today (App store says it was updated a week ago) and see totally impossible to explain values in the app when charging my new 2023 Prius Prime.

It is 90 degrees in my garage (South Florida) and Dr Prius shows charging at 3.7-4.3 amps dwelling at 4.0 Amps for pack voltages 265-285v then tapering off to (3.7,4.0, 3.7...) amps so call it 3.85A at 290v. This shows charging is happening at roughly 1.06 to 1.1 kW at the battery.

When I drove 21 miles in EV mode, the car reported "21 miles driven at 3.5 mi/kWh, SOC: 50% 5.5h to full charge."

21 miles at 3.5 mi/kWh works out to 6kWh expended. My new traction battery holds around 11kWh, so 50% SOC would say I used somewhere around 5.5kWh and have 5.5kWh left. The charging at roughly 1kW was estimated to take 5.5 hours - all seems good to this point.

Like I said, I installed the app today and discovered the charging history is available, except it shows charging took 5 hr 6 min ???, starting at 70% ??? with 3.090 kWh ???

If indeed the car was at 70%, I would indeed expect a number near 3kWh, but it was at 50% so I expect a number near 5.5kWh.

(I think charging at 4A 265v 1060W at the battery would be a minimum of 8.8A at 120v from the CCID/wall.)

There is something fishy about the charging reports from the Toyota app.

update - another charge finished:
- Drove 11.6 miles - car estimates 3h 30 min so that would be somewhere around 3kWh
- app shows the date as "Jul 7" but it is Jul 6 here EDT (UTC-4). It would indeed be July 7 UTC
- app shows correct 3h 5 min charge time
- app shows 1.648 kWh

I'm thinking the app is dividing the actual charge by a factor of 2 for some crazy reason and using the UTC date. No idea where it gets the starting SOC.

 

Trying to calculate what's expected and what's real world is a recipe for pain. If you want to start getting real world numbers put a kilawat meter between your EVSE charger cable and the wall plug.
8 Amp (max) , is what DrPrius shows my Prime charging at from 240 volt level 2 charging and around 3 Amp (max) and tapering ... when charging from 120 volt Level 1 Charging. ( ( Charging tapers slowly at the beginning and even faster at the end of full charge ) ) That ending drop off in charge rate has a lot of different names, but it is a well established charging process


Moreover. 100% SOC as reported by the Prime (cars gauges) is not 100% SOC of the traction packs total capacity. There is roughly somewhere between 10-20% total capacity buffer top and 10-20% buffer bottom that are not figured into the cars 100% to - - - SOC display.

To get even more detailed, discharge is not exactly linear when comparing SOC to voltage using the cars gauges..

The computations are not intuitive and trying to make them make sense using static math principals is difficult without getting all the processes included in the calculation(s).

 

Deleted - Wrong forum

 

Voltages do fluctuate, my home smart meter can show from 238 to 243 volts. Maybe 236. Not sure what the point is of that. Watts change?
I don’t use the Toyota app, can’t get anything from it, but Kia and other ev owners seem to have easy to see, abundant, accurate info at their fingertips.
I just wing it and charge and drive and that’s how it’s going to be.

 

it that a pun related to your username?

I've seen the northern instrumentation for the base on the rocks above Mavericks, just north of Half Moon Bay.