Charging times with Ford Mobile Charger

[RickLightning]

Just looking at at data from a public charge last night and thought the data would be relevant.

Data From Charge Point:

• Charger rating 6.6kW
• Charge time 1.5 hr
• Actual power delivered to the truck Plug. 8.81 kWh (charger never delivered more than 6.1 kW)

Weather 50 deg F, no wind.

Data from Ford app.

• Energy added to the ER battery 6% (85% to 91%) = 7.86kWh
• Distance added - 17 miles
• Calculated mi/kwh based on this charge - 2.16 (really good for me as I do love me some torque)
• Ford did not record the 16 mile Trip to this charger so I cannot verify efficiency.

Charging efficiency - 7.86/8.81 = 89.2% or 10.8% lost between charger and battery.

Let me show you how I can screw with your numbers.

1) Ford app math is lacking. Let's screw with it. 84.46% to 91.44% = 6.98kWh. Or wait, is it 85.44% to 90.46 = 5.02kWh?

2) Miles are estimated only, and are usually way overstated.

3) Efficiency calculations could be 7.86/8.81 for the 10.8% loss, or 5.02/8.81 for a 43% loss, or 20.8% loss.

4) But that's not all... When it's cold out, the battery can't accept as much juice. So, while it displays 91%, in reality it might be say 87%. So you can't use anything but the relative difference, and as I've shown that's worth crap too.

5) But wait, there's more... Some of the charging is lost to heat the battery too.

6) Lastly, if you blast the heat while charging, you have to take that into account also. Could be 4 - 6 kWhs...

If you look in the Ford app, it will show the kWh added when you're in the session, which then disappears after (big failing).

Here's some rough rules of thumb:

- DC fast charging is 7 to 10% loss
- Level 2 charging is around 15 - 20% loss

Severe heat, or cold, drives these numbers up.

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[GoodSam]

So the 50A circuit breaker to charge with (limiting the FCSP to 40A) has nothing to do with power back to the house. What is the wire size for the 9.6KW DC (direct current) feeding the inverter? Just sized like AC for 240V, 40A, #8awg? Wiring diagram:

Sorry if this diagram shows twice, tried to remove jpg.

 

[TaxmanHog]

So the 50A circuit breaker to charge with (limiting the FCSP to 40A) has nothing to do with power back to the house. What is the wire size for the 9.6KW DC (direct current) feeding the inverter? Just sized like AC for 240V, 40A, #8awg? Wiring diagram:

Sorry if this diagram shows twice, tried to remove jpg.

The DC circuit is isolated from the AC circuit, 8g 34amps at nominal pack voltage ~350-400VDC

 

[ericpullen]

Just as a data point, here is a charging session right before the cold spell, charging from 30% to 90% in 4.5 hours with my FCSP running at the full 80A it is capable of.

 

[Beans]

I know many feel 80 amps is overkill but I’m glad I wired the full 100 amps. There have been times I get home late and want to ”fill up” quickly for another trip and charging at 80 amps is great. I normally charge to 80%, thinking that’s best for the battery long term. Yesterday had a longer trip planned and hit charge to 100% when I woke up. Went from 80% to 100% in two hours, minimizing the time sitting at 100%.

 

[RickLightning]

I know many feel 80 amps is overkill but I’m glad I wired the full 100 amps. There have been times I get home late and want to ”fill up” quickly for another trip and charging at 80 amps is great. I normally charge to 80%, thinking that’s best for the battery long term. Yesterday had a longer trip planned and hit charge to 100% when I woke up. Went from 80% to 100% in two hours, minimizing the time sitting at 100%.

Ford recommends 90%, or "less than 100%" for everyday use. You should always charge to 100% for a trip where you need the range. Whether it sits at 100% for 2 hours, or 12 hours, is totally irrelevant though.

 

[Tony Burgh]

I know many feel 80 amps is overkill but I’m glad I wired the full 100 amps. There have been times I get home late and want to ”fill up” quickly for another trip and charging at 80 amps is great. I normally charge to 80%, thinking that’s best for the battery long term. Yesterday had a longer trip planned and hit charge to 100% when I woke up. Went from 80% to 100% in two hours, minimizing the time sitting at 100%.

During weather with subzero nights I set FCP to 24 amps. Insight shows several low wattage charges through the night for 9am departure.
But for charging to 100% quickly, the full 80 amps is great.

 

[Beans]

Whether it sits at 100% for 2 hours, or 12 hours, is totally irrelevant though.

Most of the info I read says length at 100% is a bigger concern than charging to 100%

 

[RickLightning]

Most of the info I read says length at 100% is a bigger concern than charging to 100%

Show me a scientific study that says that hours matter. They don't. Even a few days doesn't matter.

 

[Beans]

Show me a scientific study that says that hours matter. They don't. Even a few days doesn't matter.

Here you go.

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/154859/Woody_Maxwell_Thesis.pdf?sequence=1

“Lunz et al. show that battery lifetime can be increased by reducing the target SoC to lower values, or by minimizing rest periods at high SoC. Therefore, battery charging should occur immediately before departure [69]. Because standby times dominate battery operation, there is a large opportunity to increase battery lifetime by adjusting the time and frequency of charging (smart charging).”

 

[RickLightning]

Referenced study is from a decade ago with different technology, and still says nothing about hours. In addition, you cannot charge to 100% because Ford has locked out a piece of the battery.

People should not obsess about their batteries. I charge from 7pm to 11am. If I go on a trip, I bump the target to 100%, which gets hit probably 9 to 10 hours before departure. Doing that a dozen times a year, versus timing it to be at 100% as I leave, is not a difference that anyone is ever going to see, or even measure. If it was, Ford would have departure at 100% as a feature, which they do not.

 

[khatch]

Looks like I've gained 35 kWh in just over 29 hours so far.

 

[RickLightning]

Looks like I've gained 35 kWh in just over 29 hours so far.

Using 120v, that would make sense. With 240v, you have a problem. Check the chargers lights.

 

[khatch]

Using 120v, that would make sense. With 240v, you have a problem. Check the chargers lights.

It is 120v. That's all I've got at this point.

 

[RickLightning]

It is 120v. That's all I've got at this point.

Then that's what you get.

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