Charge past 100%? (In theory)

[mikeinet]

Does anyone else get the impression that the car will actually charge past what Ford shows as 100%?

scenario today (but also a few other times too)
-normally charge car to 85% at home
-set car to precondition (plugged in)
-went on ~14mi drive
-saw at least 10-15% drop in battery charge (don’t exactly remember). FordPass shows used 4.3kWh
-destination had an L2 charge. Plugged in for giggles (why not get free power if I have to pay for parking anyway…) — forgot that I didn’t set it to charge to 85% as a new location
-come back to battery at 100% approx 3hr later. Did NOT precondition or remote start prior to coming back
-drive home… and only use like 2% battery - FordPass says 3.5kWH (this journey 9.9mi)

Seems kinda weird… no?

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[SpaceEVDriver]

There are several conversations about this.
https://www.macheforum.com/site/thr...100-not-just-my-88-kwh-useable-battery.15125/

The reality is that the capacity of the battery is dependent on several factors, the two main ones being the temperature of the battery and the discharge rate.

For example, if your battery is cold, it will be able to hold fewer kWh. If you discharge it too quickly, you would have access to fewer kWh.

The battery is not like a gas tank where it has a specific, well-defined volume. The number advertised is based on a specific temperature and discharge rate.

However, it's more likely that your driving style used less energy than you're used to, including extra regen.

 

[mikeinet]

Not sure about driving style... was literally same drive (mostly highway, no traffic, same speed)

Temperature... I could get around that. It was warmer in the afternoon.

Thanks for that other thread.

Wish we could see like actual charge, not a calculated %... just variation always makes me raise eyebrows with trust

 

[SpaceEVDriver]

Not sure about driving style... was literally same drive (mostly highway, no traffic, same speed)

Temperature... I could get around that.

I just figure Ford would show a different % or something, just seems weird

When the battery is warm, there's also less internal resistance, so it costs fewer kWh to push the energy to the motors.

 

[Nklem]

Ford uses an algorithm to calc displayed battery percentage. Here is a graph of a recent trip. Displayed (D) vs real state of charge.

 

[mikeinet]

When the battery is warm, there's also less internal resistance, so it costs fewer kWh to push the energy to the motors.

How long does it take the battery to cool?

Car had sat unused for ~18hrs... drove for 30min... parked for 3hrs... then drove 30min home

 

[mikeinet]

Ford uses an algorithm to calc displayed battery percentage. Here is a graph of a recent trip. Displayed (D) vs real state of charge.

Which one is displayed on the screen?

 

[Dylancch]

The car is either pre heating or top balancing

 

[SpaceEVDriver]

How long does it take the battery to cool?

Car had sat unused for ~18hrs... drove for 30min... parked for 3hrs... then drove 30min home

That doesn't seem like the battery was much warmer on the way back.
What was the environmental temperature difference between your trip out and your return?
What was the elevation profile?

 

[Mach1E]

Not sure about driving style... was literally same drive (mostly highway, no traffic, same speed)

Temperature... I could get around that. It was warmer in the afternoon.

Thanks for that other thread.

Wish we could see like actual charge, not a calculated %... just variation always makes me raise eyebrows with trust

Actual charge would probably make people confused and angry.

We would have daily threads on “why won’t my battery charge past 87%?, it’s only 10 degrees out.”

And if they used KWh instead of %, it would confuse people even more.

Just think of 100% as the “current maximum,” and just know it’s a moving target based on a lot of factors.

FWIW, every cell phone you’ve owned charges the same way.

 

[SpaceEVDriver]

Actual charge would probably make people confused and angry.

We would have daily threads on “why won’t my battery charge past 87%?, it’s only 10 degrees out.”

And if they used KWh instead of %, it would confuse people even more.

Just think of 100% as the “current maximum,” and just know it’s a moving target based on a lot of factors.

FWIW, every cell phone you’ve owned charges the same way.

Very much this. They have to publish a size to allow comparisons with other vehicles. The size chosen is kWh because it's a not-terrible metric of chemical potential energy stored in the battery.

And they have to give us some numbers to allow us to estimate when we have to stop to recharge.

 

[SpaceEVDriver]

Also, nobody discusses the fact that the density of gasoline is temperature-dependent and changes by about 8-10% from about -15 C to 40 C, which means the energy content of a gallon of gasoline also changes by about 8-10% through that same temperature range. If you fill a half-full tank when it's hot out, your full tank will not actually contain as much chemical potential energy as it would if you filled it from half to full in the winter.

(The underground storage tanks tend to keep their fuel at approximately a constant temperature throughout the year.)

 

[mkhuffman]

Which one is displayed on the screen?

SOCD is SOC Displayed. So that is the one you see on the dash.

Get an OBDII scanner and the Car Scanner app and you can track all the data you could ever want to know about your car.

 

[SnBGC]

Not sure about driving style... was literally same drive (mostly highway, no traffic, same speed)

Temperature... I could get around that. It was warmer in the afternoon.

Thanks for that other thread.

Wish we could see like actual charge, not a calculated %... just variation always makes me raise eyebrows with trust

Nobody can see actual charge since we are talking about electrons. Best the car can do is estimate the percentage based on several variables. It isn't exact. This is why we see small variances day to day. If you drive enough, then you can work out the averages.

 

[AKgrampy]

Also, nobody discusses the fact that the density of gasoline is temperature-dependent and changes by about 8-10% from about -15 C to 40 C, which means the energy content of a gallon of gasoline also changes by about 8-10% through that same temperature range. If you fill a half-full tank when it's hot out, your full tank will not actually contain as much chemical potential energy as it would if you filled it from half to full in the winter.

(The underground storage tanks tend to keep their fuel at approximately a constant temperature throughout the year.)

We did on a regular basis! Fricken crews would fill up rigs at end of shift at -20F and then park indoors. Come in next day to a diesel spill!

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