Doubled My Battery Energy (by simply warming up battery)

[Mach-Lee]

Left my car parked outside in -23ºF conditions. Battery showing about 20 kWh available at 49%. Later today, I had plugged it in, charged it to 50%, and set a departure time (which warms up the battery). This time I had 41 kWh available, which means I doubled my energy! This is because cold batteries lose their energy capacity. By simply warming up the battery, you can get WAY more energy out of them. Plug your car in when it's cold!

FYI, you can only get the battery up to 55ºF if you are charged to your target %, are plugged into a Level 2 charger 240V/>28A, and set a departure time. The battery will rapidly cool off once you start driving, so you want maximum temp to start a long trip in the cold.

The app is Car Scanner BTW.

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[matwlev]

Really good info! I'd be interested in knowing how much just charging the battery on a level 2 charger warms it up. Also, how much of a difference does it make if my charger is set 48A, 40A, 32A, or lower? Like, is there any benefit to slower charing speeds because they keep the battery warm?

 

[Montievans]

I agree to an extent but hasn’t your external temperature increased by almost 30 degrees! That will make a big difference. You need to do this exercise with the same outside temp

 

[Mr.GVAK]

Really good info! I'd be interested in knowing how much just charging the battery on a level 2 charger warms it up. Also, how much of a difference does it make if my charger is set 48A, 40A, 32A, or lower? Like, is there any benefit to slower charing speeds because they keep the battery warm?

I don’t believe the L2 charge rate makes a significant difference. What really matters is setting a departure time, since that preconditions the battery and also warms or cools the cabin.

 

[ryannix123]

I'll have to try that. Right now, it's -5 where I'm at and I've seen a roughly 44% reduction in range.

Heat pumps in general add about 10% more winter range compared to resistive heating alone. My 2022 Mach-E Premium does have a heat pump, but it's an earlier design that's less effective in extreme cold (e.g., below ~20°F), where it often falls back to less-efficient resistive heating.

 

[MadMatt]

Do you think the SoH % is affected by the average temp the battery is always at? (When charged to 100%).

My 14month old LFP with about 30k on the odo (18k miles) is showing 93% state of health (about 70kwh compared to 76kwh when it was brand new). A bit lower than I had hoped at this point. I know LFP’s have a sharper initial health drop and then stabilize for the majority of its life however I was wishing something closer to 95% at this point.

anyway, all to say my battery rarely gets over 20c. I know from experience LFP’s are happiest at 30c. I wonder if the battery was able to spend more time at a higher temp it would affect the health %.

to your point, I have noticed the same thing. My Mach was left outside all day while skiing and even though it got a bit of a charge the reported available KWh was wayyy lower than it should of been with a Bat temp around -5c.

 

[dalola]

Really good info! I'd be interested in knowing how much just charging the battery on a level 2 charger warms it up. Also, how much of a difference does it make if my charger is set 48A, 40A, 32A, or lower? Like, is there any benefit to slower charing speeds because they keep the battery warm?

Not sure about that... I would guess the opposite might be true, but it's likely fractional. The biggest issue with lower amp charging is, it won't warm the battery if you are below 28A, if I understand correctly. I charge at 16A, but I'm also in a heated garage, so not a huge concern for me.

 

[Snakebitten]

A 2022 Mach-E had a heat pump?

I thought that was a 2025 option

 

[sglewiswl]

So what is my 2021 Mach-E standard battery doing here? And to be the bastard step-child this is on a L1 charger.

 

[luckie]

I'll have to try that. Right now, it's -5 where I'm at and I've seen a roughly 44% reduction in range.

Heat pumps in general add about 10% more winter range compared to resistive heating alone. My 2022 Mach-E Premium does have a heat pump, but it's an earlier design that's less effective in extreme cold (e.g., below ~20°F), where it often falls back to less-efficient resistive heating.

Umm, the Mach-E made by Ford did not have a heat pump in 2021, 2022, 2023, & 2024 vehicles; it first arrived in the 2025 model year (and it's easy to tell since the frunk is tiny in cars with a heat pump). I"m guessing you mis-typed "does have" instead of what you intended to be "does not have".

 

[ryannix123]

Umm, the Mach-E made by Ford did not have a heat pump in 2021, 2022, 2023, & 2024 vehicles; it first arrived in the 2025 model year (and it's easy to tell since the frunk is tiny in cars with a heat pump). I"m guessing you mis-typed "does have" instead of what you intended to be "does not have".

No, I actually did think it had a heat pump, but I'm mistaken. It's Tesla's that have had a heat pump since 2021, not MMEs.

 

[Mach-Lee]

I agree to an extent but hasn’t your external temperature increased by almost 30 degrees! That will make a big difference. You need to do this exercise with the same outside temp

I pulled the car into my garage to plug it in and heat the battery, that’s why. But the energy parameter is related to the battery temperature, not the external temperature. If I back the car out into the cold after heating it the kWh would be the same because the battery would still be warm.

 

[Billyk24]

Setting a departure time will heat the battery to 55f? Or is it 59f? I believe it can hit 59f but that also depends upon the garage temperature. Note how cold your garage is/was as a referenced inthe post. Or is it higher if you are level 2 charging while approaching a set departure time?

 

[933233311602]

and set a departure time.

How does this compare to simply starting the car, while plugged-in, prior to driving it?

How much time before driving is needed to make a difference?

How effective is setting a departure-time for every morning, without knowing exactly when the car may driven? Does the battery retain conditioned heat for ... just minutes ... hours ... ? Edit: you answered this one before.

 

[Mach-Lee]

How does this compare to simply starting the car, while plugged-in, prior to driving it?

How much time before driving is needed to make a difference?

Just leaving it plugged in will leave the battery temp around 0ºC, so the energy increase would be proportional. Maybe 1.5x instead of double.

For the full effect, I would say you need to set the departure time at least an hour in advance. Because in some cases it takes more than an hour to heat everything up. If you set it sooner, like a half hour in advance, you will only get minimal battery heating.

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