Anyone done a deep dive into real Level 2 charge efficiency?

[Zaptor]

I have nothing to add other than...

Bar Harbor! I spent my summers as a youth in Salisbury Cove

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[Nklem]

I have nothing to add other than...

Bar Harbor! I spent my summers as a youth in Salisbury Cove

Cool. I live 4.4 miles from Salisbury Cove. There are quite a few Lightnings on the island. At least 10 and probably more. A great Island vehicle…

 

[Newton]

Oh yeah, still loving ours. Even with 160ish range between charges we still stop more than we charge. I have learned that Wall*Mart restrooms - although not fancy - are much better than the rest area bathrooms around here, and light years above what I remember gas stations were like. One of the hidden benefits of an EV. I just wish that Costco was on the EV train, I'd actually buy stuff there.

 

[Adventureboy]

Last Saturday night I added 69kw to the truck and my Emporia measured 77kw consumed. Roughly 90% efficient running 32 amps. I'll run it again this weekend at 48amps and see where it lands, but I'd guess 90% efficiency will be pretty close for most L2 charging.

 

[Lytning]

Attached are results of a few representative home charge sessions with a Ford Charge Station Pro at 32 amps.

KW @ TED = KW measured by The Energy Detective TED 5000 energy monitor on charge circuit.
KW @ CSP = KW measured by Charge Station Pro as reported by FordPass app.
CHG EFFIC. = KW @ CSP divided by KW @ TED times 100.

Efficiencies are generally between 92% and 95%.

 

[Adventureboy]

Recently I had a charging session that showed that I added 40 kWh raising the SOC from 85% to 90%, that 40 kWH was clearly bogus, your shot is closer to reality though still optimistic 112/44.4 @ 2.52 MPK.

I've been tracking the Fordpass reported session kWh, with the FCSP records and my Emporia Vue2 energy monitor which exclusively tracks the 240vx80a feeds, comparing these measurements against the anticipated energy based on the delta of displayed SOC.

Awesome tracking. Do you always charge at the full 80 amps? Just curious if you see a difference in efficiency if you charge faster or slower.
If you have this in a spreadsheet, you can work out the efficiency (probably Fordpass KWH/FCSP KWH would give a pretty accurate efficiency).

I'm guessing you don't use Departure Times? That might affect efficiency pretty dramatically on cold days in Mass. A spot check suggests not since you are running around 91% on the few I checked.

 

[TaxmanHog]

Awesome tracking. Do you always charge at the full 80 amps? Just curious if you see a difference in efficiency if you charge faster or slower.
If you have this in a spreadsheet, you can work out the efficiency (probably Fordpass KWH/FCSP KWH would give a pretty accurate efficiency).

I'm guessing you don't use Departure Times? That might affect efficiency pretty dramatically on cold days in Mass. A spot check suggests not since you are running around 91% on the few I checked.

These data points are all at the 80 amp setting, the FCSP control app is so unpredictable with making amperage changes I hesitate to fool around, I could pull the cover and dial in but that's a PIA.

 

[Adventureboy]

These data points are all at the 80 amp setting, the FCSP control app is so unpredictable with making amperage changes I hesitate to fool around, I could pull the cover and dial in but that's a PIA.

I wouldn't worry about pulling the cover. I'm testing this weekend at 48 amps and will compare what I get at 32 amps and what you get at 80 amps. I suspect they will be pretty close to your 91% give or take a percent.

 

[OMO7]

Is there a charge rate that has an optimal efficiency?

My Emporia said I added 19.81 kWh while the FordPass history says +20kWh. I imagine that's rounding, but why aren't I seeing any loss?

 

[TaxmanHog]

My Emporia said I added 19.81 kWh while the FordPass history says +20kWh.

Are you using the Vue2 or is this the stats directly from the Emporia EVSE?

 

[OMO7]

Are you using the Vue2 or is this the stats directly from the Emporia EVSE?

EVSE

 

[TaxmanHog]

EVSE

Ok, good to know how your getting EVSE data.

The new charge session record now showing total kWh of energy dispensed is not reliable, I've seen grossly inaccurate data.

 

[chl]

Getting an accurate SOC in Li batteries is problematic, the voltage discharge curve is very flat. Therefore, small voltage changes are involved between say 90% and 100% SOC, and the smaller the voltage change the less accurate the estimate.

So knowing how many kWhrs actually went into the battery is difficult. And the Lightning is no Einstein.

Generally, EVSEs will lose between 5% and 10% during charing, mainly due to wire/conductor resistance/heat, then you have the AC to DC conversion system in the vehicle which will "waste" energy, then the battery itself has thermal and molecular losses.

As others said above, there are many factors that will contribute to energy loss/inefficiency during charging.

Be happy that it only cost about $5 to $10 of electricity vs the $ it would have cost to fill an ICE with gasoline.

You said your "ChargePoint Home, with utility grade metering, shows the truck actually took 47.3249 kWh" so accept that the battery probably got 90% of that energy. The on-board guesstimates are not going to be exact because of the difficulties involved in determining the SOC of Li batteries.

You didn't say where the metering was measured. So should we assuming it is being measured at or by the EVSE?

If you are measuring the kWhrs at the service, then you have to account for the resistance losses between the service and the EVSE due to the resistance per length of wire, the current it is carrying squared and the time involved (R x I x I x T).

I am an electrical engineer with a masters degree.

For further reading see: https://www.powertechsystems.eu/home/tech-corner/lithium-ion-state-of-charge-soc-measurement/

"...Lithium-ion batteries have a much flatter discharge curve, which means that over a wide operating range, the voltage at the battery terminals changes very slightly.

Lithium Iron Phosphate technology has the flattest discharge curve, which makes it very difficult to estimate SoC on a simple voltage measurement. Indeed, the voltage difference between two SoC values may be so small that it is not possible to estimate the state of charge with good precision..."

 

[Grumpy2]

,

 

[Nklem]

thanks for all the replies. I posted another thread yesterday as I used CarScanner Pro to monitor the truck and charger data points all day while I charged at work, and from the at work data, 91.4% charger efficiency. The issue from the other day had to be Fords battery kWh estimates are not the most accurate as reported. Great news!

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