Mississippi Cooling the battery before charging

[dbrown310]

According to the manual...

...you should allow the battery to cool before charging.
Unfortunately, Ford doesn't provide any guidance on the length of time you should wait.
How long would you recommend waiting for the batteries to cool before plugging in?

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[macchiaz-o]

According to the manual...

...you should allow the battery to cool before charging.
Unfortunately, Ford doesn't provide any guidance on the length of time you should wait.
How long would you recommend waiting for the batteries to cool before plugging in?

Don't wait. Just plug in when you get home.

If you're on a time of use plan, set the vehicle to charge during the hours where you pay the lowest rates... The car will sit and cool down, while plugged in, and will start charging on the schedule you set.

 

[RickMachE]

That assumes you don't park it during the off-peak hours. Our peak is 11am - 7 pm M-F, so we can drive it in the early morning and arrive home at 10AM and begin charging.

And, driving on the highway and using DC chargers allows no cooling time. Ford knows this. They design the vehicle for it.

Relax, and drive your car. If you live in a very hot climate, then maybe make adjustments to the charging schedule.

And remember, Ford's goal is to significant beat their warranty promise of 70% battery capacity in 8 years / 100,000 miles. I don't expect to keep the Mach-E that long due to ever changing technology including range improvements.

 

[John_C]

According to the manual...

...you should allow the battery to cool before charging.
Unfortunately, Ford doesn't provide any guidance on the length of time you should wait.
How long would you recommend waiting for the batteries to cool before plugging in?

I've been poking around on the internet for some information about EV battery degradation for a while now -- ever since I took delivery on my Mach E in March. The best thing I've seen is this article from Electrek, which is a great online newsletter covering the EV industry.

This is the relevant part of the article:
---
A persistent concern among some EV drivers is the long-term health of the battery. All batteries lose some storage capacity over time. But how might that degradation affect your driving range a few years down the line? To help answer that question, we can now look to Geotab, a leading telematics-fleet-management company with access to a lot of EVs. Lo and behold, the losses are minor.

Geotab created its so-called EV Battery Degradation Tool by pulling data directly from the 6,300 EVs from its fleets. What’s super-cool is the interactive nature of the tool, allowing users to drill down to 21 specific electric models.

You can use the tool to slice and dice the data for yourself.

In June 2018, Geotab acquired FleetCarma, a forerunner in providing technology support the use of EVs in fleets.

Here’s a quick rundown of what the data revealed:

• If current degradation rates are maintained, the vast majority of batteries will outlast the usable life of the vehicle.
• The average decline in energy storage is 2.3% per year. For a 150-mile EV, you’re likely to lose 17 miles of accessible range after five years.
• EV batteries decline in a non-linear fashion. There’s an early drop, but the rate of decline slows down in subsequent years.
• Liquid-cooled batteries decline slower than air-cooled packs. Geotab saw that a 2015 Tesla Model S with liquid cooling had an average annual degradation rate of 2.3%, compared to an air-cooled 2015 Nissan Leaf’s rate of 4.2%.
• Battery-powered vehicles that have bigger state-of-charge buffers fare better. In other words, some carmakers use a smaller percentage of the battery’s capacity, which reduces usable range. But the conservative approach slows down the degradation rate, most notably in early versions of the Chevrolet Volt plug-in hybrid.
• Higher vehicle use does not necessarily equal higher battery degradation.
• Vehicles driven in hot temperatures show a faster decline in battery health.
• The use of DC fast-chargers speeds up the process of degradation, but there’s not much difference in battery health based on frequent use of Level 1 versus Level 2 charging. Losses that happen with frequent DC charging are made worse in hot climates.

---

Here's a link to the full article. The comments section has some interesting feedback on the long-term decline in charging speeds as well:

https://electrek.co/2019/12/14/8-lessons-about-ev-battery-health-from-6300-electric-cars/

In hot weather I'm trying to use my Level 1 Ford home charger more now and high-speed DC charging less (which is too bad, because there's a great multi-port Electrify America depot about 10 minutes from my house). And here in Northern California we had a lot of hot weather this summer.

Like @RickMachE I'm trying not to worry about this too much because I expect to change models not too far from now as the technology improves. But it's still a good question ...

Right now I'm one very happy camper with my 2021 ...

 

[raitchison]

Liquid-cooled batteries decline slower than air-cooled packs. Geotab saw that a 2015 Tesla Model S with liquid cooling had an average annual degradation rate of 2.3%, compared to an air-cooled 2015 Nissan Leaf’s rate of 4.2%.

Not all liquid cooled batteries are created equal, and just having a liquid cooling system doesn't help you much if your car's BMS is loath to use it because the automaker didn't want to hear complaints from customers of "lost range" when parked on a hot day.

I'm new to the Mach-E world but I've had a Bolt since early 2018, the Bolt has a capable battery cooling system, that the BMS only dares to use under an extremely limited set of circumstances. I've recorded battery temperatures as high as 37C (~99F) without the car doing anything to cool it.

The use of DC fast-chargers speeds up the process of degradation, but there’s not much difference in battery health based on frequent use of Level 1 versus Level 2 charging. Losses that happen with frequent DC charging are made worse in hot climates.

It's likely that most of the harm from DCFC use is due to the heat that fast charging induces in the battery, with cars that are smart enough to pre-cool the battery as you are approaching a charging stop (or in theory, cars that trust their drivers enough to allow them to initiate battery cooling manually) able to do better here. Again with my Bolt (my only point of reference) the battery cooling will kick in as soon as you plug into any charger (so long as the battery is above ~27C and you leave the car turned on) but the best it can do is keep up with the heat generated by DCFC. So a common scenario has you immediately start tapering the charge (which tops out at ~55kW under the most ideal situations) while the battery cooling system works to maintain a battery temp in the 33C-35C range.

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