DC/Level 3 Charging to 100%: What is your comfort level?

Usually in Quebec, Canada, for road trip and vacance, we have enough DC Fast charger along the road, so I didn't charge over 80%. Lost of time, money and battery capacity over time.

For that kind of usage, I change my current limit of L2 charging from 80% to 100 % and revert it back afterward.

 

Cars automatically slow everything down after 80% anyway so, in effect, charging to 100% on DCFC shouldn't be much different from slow charging to the same level. That's certainly been my understanding.

 

Not completely. Charging on DCFC has the side effect on heating way more the battery than L2 charging. Battery degradation will be faster if used often. Heat kill battery.

 

Yes, I know that DCFC overall is seen as less battery-friendly with heating being the culprit but I believe the question was essentially is 100% of charge derived by DCFC worse than charging to 100% at lower powered stations. I don't recall ever seeing any evidence that there's a difference.

 

As mentioned the added cost and time as the Kona manages DC charging after 80% plus the battery degradation issue make this an “only if necessary” occurrence for me. I haven’t ever gone to 100% in two years of ownership but may need to in a few weeks when on a road trip to Wyoming

 

By "comfort level" I assume you're referring to being kind to the battery? I'm waiting for a new battery so am not allowed to charge over 90% but once replaced I would have no concerns charging to 100% DC or AC if I was starting off on a trip or had the time to top-up that much during a trip.

It's the "time at 100%" that should be minimised, don't worry about the process of getting there, especially on AC, or 25 and 50kW DC. But I'd avoid higher the charge rates if it was not inconvenient to do that because they may exceed "1C" of the cell capacity which is 180 amps.

Same applies to being under 20%, don't leave it there overnight if you don't have to.

 

I only fast charge on the road, therefore drive right after. 100% with no reservation.

 

Reading the Owners Manual states the, time, to 80% plus "can be charged to 100%" on both DC 100kW and 50kW. (see chart Charge Time Information on page 1-17 owners manual). But it warns the use of DC charging should be "minimized" to prolong battery life. So I think DC charging to 80% or 100% is irrelevant, its the act of DC charging, period, that damages the high voltage battery.


(From the Owners Manual, DC Charge page 1-28)
DC fast charging (also known as Level
3 charging) provides high power DC
current directly to the EV battery. DC
charging stations are capable of charging
the EV battery to 80% in less than 75
minutes under normal conditions.
While DC charging is very fast
compared to AC charging, prolonged
and continuous use of DC fast charging
may reduce the long term life of the
EV battery. Usage of a DC fast charger
should be minimized when possible in
order to help prolong the life of the EV
battery.

 

The Owners manual recommends storing for extended periods of time at 100% battery level. Kind of makes sense to AC charge everyday to 100% is not harmful at all. But what is harmful is leaving high voltage battery below 20% over time.

(Owners Manual, High Voltage Battery (lithium-ion polymer) page 1-8)

If the vehicle will not be used for
an extended amount of time, it is
recommended to fully charge the
vehicle to 100% before storing, and
then charge the vehicle periodically
(approximately every 3 months)
to prevent the EV battery from
discharging completely.
• AC charge is recommended to keep
the high voltage battery in optimal
condition.
Avoid storing the vehicle with a low
battery SOC % (e.g. below 20%).
Storing the vehicle with the EV battery
capacity at a low SOC may damage
the battery over time.

 

Not driving and having vehicle in a too hot or cold will degrade battery.

(owners manual from page 1-7)

• The charge amount of the high
voltage battery may gradually
decrease when the vehicle is not
being driven.
• The battery capacity of the high
voltage battery may decrease when
the vehicle is stored in high/low
temperatures.

 

Good luck on that trip. Wyoming, like the Dakotas, is way short on DCFC charging opportunities.

 

I have never investigated this but I am wondering. If the vehicle has active battery systems (heating/cooling) is it not utilized during charging to protect the battery?

 

I see lots of opinions here, but that is all. Need an expert to weight in on this. Right now, just follow the manual directions.

 

I'm not an expert but I trust this site, which say the "usable capacity" of the Mustang Mach-e with Extended Range (what I have) is 91 kWh. But the *total capacity* is 98.8 kWh.
https://insideevs.com/news/537347/mustang-mach-e-range-battery/

Which means the car isn't even allowed to charge to 100%. Ford is accounting for the exact concerns expressed here.

I charge to 80% at home (ie, almost always), and to 100% on road trips just to have one less hassle to think about. No ill effects noticed, road trips (up and down the West coast) have been easy and fun.

 

The number one reason to Fast Charge Level 3 to 80% is cost. Above 80% charging slows down and costs. You can get anywhere across Canada or up and down the west coast of the USA easily. There are always plenty of stations available. I use plugshare for planning stops and over time have found favorite places to charge. That said, according to Battery University you can charge daily (say for a commute) 250 xs a year. That would be 1000 xs every four years. Say you drove for 16 years, fast charging daily, from 25% to 100%, you would still have 80% of your battery range. Personally, I do most of my charging at Level 1, overnight in ~12 to 13 hour shots, or 60-80%. This would pretty much keep me within the orange line. So when I travel long distance, I D/C fast charge without worry, but to 80% due to cost after 80%. With good planning, I can travel about anywhere with no problem. BTW most people get a new vehicle every 5 to 6 years. Your EV battery is the least of your worries. Personally, I plan to keep mine for 20 years, depending on how new technology speeds up the charging time.