Charging Discrepancy

[TD1273]

Let's say you charge to 80% but I've noticed that my chargepoint at home shows that the car recieved 45kwh to charge it to 80 % but the Ford app shows it that only took 40kwh to charge it to 80% so has anyone else noticed this discrepancy and if so which one do you believe is right if either.

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[Mach-Lee]

45 kWh = energy from the wall (ChargePoint)
40 kWh = energy into the pack (FordPass)

40/45 = 89% charging efficiency

Charging is not 100% efficient. ChargePoint measures the total energy from the wall, while FordPass only measures the energy going into the pack after charging losses.

 

[geftsnowball]

Chargepoint gave you 45kWh - charging loss = 40kWh delivered to your vehicle.

Basically not all of the energy delivered can be stored in the battery (due to losses in the delivery process).

 

[ADDZ71]

I find that the efficiency changes depending on a number of factors but the biggest I think is amperage/power delivery rate. More heat is generated at higher amperages creating greater losses. If the time to receive a charge is not critical I suggest charging at a lower rate. For example, I have my Chargepoint Flex set at 32A rather than the 40 or 48 it is capable of.

 

[Benny’66]

I find that the efficiency changes depending on a number of factors but the biggest I think is amperage/power delivery rate. More heat is generated at higher amperages creating greater losses. If the time to receive a charge is not critical I suggest charging at a lower rate. For example, I have my Chargepoint Flex set at 32A rather than the 40 or 48 it is capable of.

Have you ever collected data on this? Since my home charging is always overnight, I may make this change as well on my CP Home Flex. I predominantly charge at work now (so efficiency isn’t as important), but if I can save a few bucks at home, why not. This mornings work charge was Autel delivered 30.05 kWh and car accepted 27 kWh. So about the same 90% the OP saw.

Of course it is 26deg out this morning so that has an affect.

 

[ADDZ71]

Have you ever collected data on this? Since my home charging is always overnight, I may make this change as well on my CP Home Flex. I predominantly charge at work now (so efficiency isn’t as important), but if I can save a few bucks at home, why not. This mornings work charge was Autel delivered 30.05 kWh and car accepted 27 kWh. So about the same 90% the OP saw.

Of course it is 26deg out this morning so that has an affect.

I just use Thermodynamics as my guide. The cooling fans come on at anything above 32A in summer weather suggesting that the inverter is generating excessive heat.

 

[RickMachE]

I just use Thermodynamics as my guide. The cooling fans come on at anything above 32A in summer weather suggesting that the inverter is generating excessive heat.

In the heat of summer, in Texas, maybe. In most places, rarely. In winter, unlikely.

 

[RickMachE]

Have you ever collected data on this? Since my home charging is always overnight, I may make this change as well on my CP Home Flex. I predominantly charge at work now (so efficiency isn’t as important), but if I can save a few bucks at home, why not. This mornings work charge was Autel delivered 30.05 kWh and car accepted 27 kWh. So about the same 90% the OP saw.

Of course it is 26deg out this morning so that has an affect.

Let's do the math. Your 11% loss (stated above) charging the car from 20 to 90% on a ER, with 15 cents per kWh, as compared to a 15% loss.

91 x 70% = 63.7kW / .89 = 71.6kW x 15 cents = $10.74
91 x 70% = 63.7kW / .85 = 74.9kW x 15 cents = $11.24

Net POSSIBLE savings = 50 cents

If you did this once a week, you'd save $26 a year. I have mine set on 32amps, rarely do I raise it to 48amps.

 

[Benny’66]

Let's do the math. Your 11% loss (stated above) charging the car from 20 to 90% on a ER, with 15 cents per kWh, as compared to a 15% loss.

91 x 70% = 63.7kW / .89 = 71.6kW x 15 cents = $10.74
91 x 70% = 63.7kW / .85 = 74.9kW x 15 cents = $11.24

Net POSSIBLE savings = 50 cents

If you did this once a week, you'd save $26 a year. I have mine set on 32amps, rarely do I raise it to 48amps.

Hmmmmm, not sure the annual savings is worth forgetting to change the amps up when in need that little extra speed on a Friday night. Thanks for the calcs though.

 

[AKgrampy]

I just use Thermodynamics as my guide. The cooling fans come on at anything above 32A in summer weather suggesting that the inverter is generating excessive heat.

I believe there are more losses in the charger and ancillary equipment during charging in the car than in the cable so less time charging results in less losses. I charge at 32 amps myself just to keep the cable, etc from warming up as much. I did compare the efficiencies after I dropped down to 32 amps from 38 amps and the efficiency was slightly better at 38 amps. (At least to the best of my measurement abilities)

 

[ADDZ71]

I believe there are more losses in the charger and ancillary equipment during charging in the car than in the cable so less time charging results in less losses. I charge at 32 amps myself just to keep the cable, etc from warming up as much. I did compare the efficiencies after I dropped down to 32 amps from 38 amps and the efficiency was slightly better at 38 amps. (At least to the best of my measurement abilities)

yeah that makes sense. probably a balancing act of higher current generating more heat versus heat loss in the cable. It is likely a balancing act and probably more effort to resolve which is the best than to just choose what works for the user. Probably something to consider for me since from a $/cents perspective I should charge really fast for a shorter period when my ToU rate is the lowest. The offset is that I rarely need to get a full battery so if it takes more than a day to recover it probably is not that big a deal. Most of my battery depletion occurs randomnly rather than every day.

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