That's really the question: Does the charging curve hold peak kW longer, or taper rather quickly? Ford's "45 minutes for a 10-80% charge" suggests a quick taper to get the numbers to fit. 39 minutes would be a more gradual taper, as you suggest.I've been giving this topic of charge speed a lot of thought lately. I'm a numbers person so I ran some numbers and possible charging curves scenarios. The one that matches best with the Ford facts and other similar packs is below.
I used a smooth curve, not one that steps down drastically.
At a 10% state of charge, the MME will be able to add 61 miles (3.4m/kWh) in 8.5-9 minutes, not 10. This on a "150kW charger". It will be a little faster on the 350kW charger as it pushes more amps. I think this is an everyday charging speed not the perfect 150+kW speed in perfect conditions. On those days I think the 150kW charge speed will last 5-9 minutes. On those perfect days, I would expect to get 76 miles in ten minutes. (warm pack, warm air, perfect juice coming out of a 350kW charger. The local power quality is very important for peak speeds. With a hot or cold pack or hot/cold air, charging will be slower.
At 10% state of charge, the MME will be able to add 150 miles in 25 minutes. (10%-60%) I then, I believe it will be another 14 minutes to get to 80% (39 minutes total), as the curve flattens out. The extra 20 minutes Ford quoted from 60-80% would require the charging speed to drop quickly to 52kWh which is possible but does not match the charging profile of packs similar to that of the MME's. If this was the case though, most people will just stop charging at about 60% while the charging is still in the 80-85kW speed.
*All the mileage numbers assume 3.4 miles per kWh. We will see what the EPA says soon. All these are also based on the 88kWh pack, using 88kWh as 100%.
These are my predictions.
If the Mach-e held 150 kW all the way to the 80% SOC point like the e-tron, it would do a 10-80% charge in 25 minutes. And Ford would be screaming it from the rafters.The charge time to 80% that I'd like to see Ford beat is Audi e-tron. That's about 30mins or so and it would be about on par with Tesla Model 3/Y.
Maybe, maybe not. I just know that 45 mins is too damn slow. 39 minutes is obviously better but e-tron's 30 mins should be the goal. It's doable on 400v systems but Ford has to be willing to open it up to let the charge rate zip along.If the Mach-e held 150 kW all the way to the 80% SOC point like the e-tron, it would do a 10-80% charge in 25 minutes. And Ford would be screaming it from the rafters.
What folks are failing to understand here is that the Mach E is designed to be a mass market car, the E-Tron is not. A mass market vehicle has to have some sacrifices. Don't forget we are comparing two completely different priced vehicles.Maybe, maybe not. I just know that 45 mins is too damn slow. 39 minutes is obviously better but e-tron's 30 mins should be the goal. It's doable on 400v systems but Ford has to be willing to open it up to let the charge rate zip along.
I'm not sure I follow. How is the Audi e-tron not a mass market vehicle?What folks are failing to understand here is that the Mach E is designed to be a mass market car, the E-Tron is not. A mass market vehicle has to have some sacrifices. Don't forget we are comparing two completely different priced vehicles.
Oh I absolutely agree that it's too slow for most mainstream consumers' tastes. And thus will keep BEV penetration in check until they can greatly improve that at a more affordable price.I just know that 45 mins is too damn slow
Lots of good points. I'll throw in another factor... road trips are usually high speed highway driving. Mileage can easily drop 20% in a BEV at high speed. To stop and recharge at the 60% SOC point (i.e. drive in the 10-60% window), that's half the overall range (135 on the 270 mile AWD ER Mach-e). Then subtract 20% for high speed, and we're down to 108 miles.One of the reasons I was running the numbers is that I wanted to see the time difference between charging to 80% versus just 60% (and stopping sooner), as compared to the time it takes to exit the hwy, plug-in, pee, etc., and get back on to the hwy.
The six-minute difference (see above) between a car that holds ~80kW and one the falls to ~50kW between 60-80%, is probably about the amount of time you lose by exiting, parking, plugging in, unplugging, and getting back on the hwy for a charger that's located right at an on/off-ramp.
So it's about the same amount of time but currently, it will cost more to stay and charge at a slower rate using EA (and most others) that charge you by the minute. However, if you have to drive a mile, navigate a busy parking lot and a bunch of stoplights then you can see that it will be better to continue charging to a high enough state of charge so you can skip to a charger or two and continue to one that is further down the road and less of a detour.
My first EV road trip was 1100 miles all done on level 2 charging from LA to Seattle. My current tolerance is one, maybe two stops before I get to my destination.
Yes, and add to the frequent stopping you have to go by where the charger is placed along your route. EA stations try to be about 70 miles apart. So do you go 70 or 140 miles?Lots of good points. I'll throw in another factor... road trips are usually high speed highway driving. Mileage can easily drop 20% in a BEV at high speed. To stop and recharge at the 60% SOC point (i.e. drive in the 10-60% window), that's half the overall range (135 on the 270 mile AWD ER Mach-e). Then subtract 20% for high speed, and we're down to 108 miles.
That's gonna be a pretty low leg-limit for a lot of people's tastes.
I think the 70 vs 140 mile conundrum is a short-term problem as more DC chargers and especially HPCs come online. That's not to dismiss the concern entirely, I'm just saying it's likely not a permanent state.Yes, and add to the frequent stopping you have to go by where the charger is placed along your route. EA stations try to be about 70 miles apart. So do you go 70 or 140 miles?
And don't forget, there are often EVgo, ChargePoint, etc. between the EA stations. Unlike Tesla, we're not limited to a single supplier (or slow-speed kludges like CHAdeMO adapters).I think the 70 vs 140 mile conundrum is a short-term problem as more DC chargers and especially HPCs come online. That's not to dismiss the concern entirely, I'm just saying it's likely not a permanent state.