Linearity in Range vs Battery SoC%?

[Mach-Lee]

Also, I know that in the Powerboost, the hybrid algorithm keeps our battery's reported SoC% between ~40% at the low end, and 60% as the cutoff where ICE won't charge it anymore, and regen braking charging stops around 70%. Basically it keeps the battery always 40-70%! So Ford intentionally keeps it in that band to extend the life. In watches/phones, the IC's used for charging algorithms are really good about using all kinds of conditions to not overwear or kill the Li-ion cells when up near 100% or down around 0%, but I know NOTHING about how EV's do it.

The big difference between a hybrid and a BEV is the hybrid will cycle the pack way more times, so capacity retention becomes much more important in a hybrid. A cycle is one complete drain and recharge. If you drive 200 miles a hybrid, that could cycle the pack 10 times, whereas a BEV would only be one cycle. Typical lithium battery life is about 500-1000 cycles, which means the battery in a hybrid might wear out in only 20,000 miles if protection measures aren't taken. Therefore you see a 40-70% limit programmed into it so the pack will last 100,000+ miles. If you kept your BEV between 40-70% the battery would last forever, but it wouldn't be practical due to the short range available. Therefore it's okay to go further into the pack and still have it last 100,000 miles since the pack is much larger. If you want to make 100,000 miles for sure, keep it between 10-90% 99% of the time. If you want more like 200,000 miles keep it between 20-80% 99% of the time.

Charge limits are all about how long the pack needs to last before replacement. It's a balance between having range and preserving the pack. Using the entire battery (100% to single digits) on a regular basis will degrade the pack quickly, you'll probably be below 80% health before you hit 100,000 miles. 70% is the threshold for warranty replacement, but most people will be sick of the poor energy delivery long before that. At 70% health the car will accelerate much more slowly than when it was new, so you really want to make sure your battery stays above 85% health for normal performance while you own it.

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[daemonic3]

The big difference between a hybrid and a BEV is the hybrid will cycle the pack way more times, so capacity retention becomes much more important in a hybrid. A cycle is one complete drain and recharge. If you drive 200 miles a hybrid, that could cycle the pack 10 times, whereas a BEV would only be one cycle. Typical lithium battery life is about 500-1000 cycles, which means the battery in a hybrid might wear out in only 20,000 miles if protection measures aren't taken. Therefore you see a 40-70% limit programmed into it so the pack will last 100,000+ miles. If you kept your BEV between 40-70% the battery would last forever, but it wouldn't be practical due to the short range available. Therefore it's okay to go further into the pack and still have it last 100,000 miles since the pack is much larger. If you want to make 100,000 miles for sure, keep it between 10-90% 99% of the time. If you want more like 200,000 miles keep it between 20-80% 99% of the time.

Charge limits are all about how long the pack needs to last before replacement. It's a balance between having range and preserving the pack. Using the entire battery (100% to single digits) on a regular basis will degrade the pack quickly, you'll probably be below 80% health before you hit 100,000 miles. 70% is the threshold for warranty replacement, but most people will be sick of the poor energy delivery long before that. At 70% health the car will accelerate much more slowly than when it was new, so you really want to make sure your battery stays above 85% health for normal performance while you own it.

Great points, excellent info, thanks a bunch!

 

[SnBGC]

If we can do 100% down to 0%, the full range is absolutely not a problem (~300mi or even ~260mi). I see a LOT of things written about only cycling the battery from 20-80% to keep it healthy. So right away we are cutting down the range big time, if you adhere or believe those recommendations. So I just wanted to hear from owners if the USEABLE portion of the battery is realistic for what I may need the car for (and not stopping for any DC fast charging on a time sensitive commute).

Forgive me as my expertise is on the micro scale (smart watches, batteries, chargers, regulators, processors, sensors and consumption thereof) and I feel like I've been cramming for a test studying everything I can for this upcoming leap into EV's. I'll get there!!

Also, I know that in the Powerboost, the hybrid algorithm keeps our battery's reported SoC% between ~40% at the low end, and 60% as the cutoff where ICE won't charge it anymore, and regen braking charging stops around 70%. Basically it keeps the battery always 40-70%! So Ford intentionally keeps it in that band to extend the life. In watches/phones, the IC's used for charging algorithms are really good about using all kinds of conditions to not overwear or kill the Li-ion cells when up near 100% or down around 0%, but I know NOTHING about how EV's do it.

EDIT: I can appreciate the "hard to follow" comment ? When I initially read it back, I was thinking anyone making it to the end without their head exploding deserves a medal!

At 75 mph, you can expect around 25 miles per 10% (assuming extended range battery pack). If you leave your home at 100% displayed then you should arrive in the bay area with 45% charge. While driving around in the bay area, you can expect around 30 miles per 10% real world.

Public L2 charging speeds can vary depending on how they are wired so just make sure you have about 65% state of charge before heading back. That should work fine.

You can charge to 100% prior to your long trips without ANY concern. Don't let the internet charge police convince you otherwise.

Enjoy your MME, whichever model you decide.

 

[Tom L]

In my opinion the only reason for AWD is performance, but I am sure others will disagree. The MME is not a high riding vehicle so it isn't like you will take it in deep snow anyway. And people have been driving RWD vehicles in the snow forever. The most important factor in bad weather is good tires.

I like mkhuffman’s take on this. I have a CR1 ER RWD and have no regrets about the RWD. I drive the speed limit and reliably get 340 miles at 100% both on the GOM and odometer.

 

[AZBill]

Yes it’s linear. The longest you should plan on doing is 100% to 10%, which is 90% of the battery. That would be about 200 miles at 75 mph.

You’re not going to be able to do 132 miles there and back without stopping to charge.

In the winter figure more like 140 miles before stopping to charge.

My RWD Route 1 easily gets 300 miles at 75mph, so 270 for 90%. That trip would not need a charging stop.

 

[devmach-e]

There are plenty of DC Fast Chargers in the downtown San Jose area, and along your path back to Sacramento. The MME will be able to handle it without a problem, even including a side trip to Santa Cruz. Santa Cruz also has DC Fast chargers, but they appear to be slower 50 kW ones.

 

[SnBGC]

There are plenty of DC Fast Chargers in the downtown San Jose area, and along your path back to Sacramento. The MME will be able to handle it without a problem, even including a side trip to Santa Cruz. Santa Cruz also has DC Fast chargers, but they appear to be slower 50 kW ones.

It sounded to me that the OP will spend several days in the bay area. If staying at a hotel, then select one with L2 and the car will be fully charged every morning. Easy peasy. I think any MME will meet the OPs needs provided they have easy overnight access to L2. If not, then public or workplace L2 and then L3 as a last resort. Lots of options IMO.... ?

 

[Mach-Lee]

My RWD Route 1 easily gets 300 miles at 75mph, so 270 for 90%. That trip would not need a charging stop.

That just seems impossible unless you are driving in traffic slowing you down below 75 MPH or going downhill. At 75 I'd imagine you get around 2.8 mi/kWh so your real range will be around 250 miles tops.

 

[daemonic3]

It sounded to me that the OP will spend several days in the bay area. If staying at a hotel, then select one with L2 and the car will be fully charged every morning. Easy peasy. I think any MME will meet the OPs needs provided they have easy overnight access to L2. If not, then public or workplace L2 and then L3 as a last resort. Lots of options IMO.... ?

Correct. My old schedule was drive Sunday 10pm, stay at condo, drive back Wed 10pm (unless I had meetings with India) or early Thurs at 6am. All were 2hrs during non-traffic time.

Our condo association has permission to use the Kaiser chargers (L2 7.2kW Semapoint) overnight as long as we move it by 7:30am.

Overall, not worried at all about being stranded, but about adding time to my commute to charge. I intentionally pick off-peak drive times to keep it at ~2hrs.

The Santa Cruz stuff will be occasional and ad-hoc. Will be fun to try to wing it, and maybe plan a restaurant near a DC fast charger (looks like there's a Whole Foods with 50kW as someone pointed out) and see how college is treating my kid.

 

[silverelan]

That just seems impossible unless you are driving in traffic slowing you down below 75 MPH or going downhill. At 75 I'd imagine you get around 2.8 mi/kWh so your real range will be around 250 miles tops.

Kyle on Out of Spec says he gets 300 miles on I-70 in the CA Rt1.

 

[devmach-e]

That just seems impossible unless you are driving in traffic slowing you down below 75 MPH or going downhill. At 75 I'd imagine you get around 2.8 mi/kWh so your real range will be around 250 miles tops.

I’m averaging 3.3 mi/kWh doing 72 to 74 MPH. However, the GOM does usually state about 220 to 240 miles of range at 90% charge. I have a fair number of hills to traverse in my area.

 

[Mach-Lee]

Kyle on Out of Spec says he gets 300 miles on I-70 in the CA Rt1.

He got 287.4 mi at 69 MPH. Extrapolating, he would get about 260 miles at 75 MPH.

 

[tesla2mme]

I'm only about a week into researching, in the interest of making our next vehicle, fully electric. I currently have a F150 Powerboost and love it, but FULL EV is a wholly different animal!

There is so much information to absorb and answers are not always consistent and information scattered, so I'm going to ask this community with REAL experience directly. The Mach E would primarily be my wife's replacement car, so Level2 home charging (between say 25-75% limits) covers everything, plus our electric company gives overnight EV rate of 8.5c/kWh which is outstanding. Done deal, any Mach E will do.

Now for my concern and anxiety! If I have to commute once per week for a few days at a time to the bay area again (132 miles each way), it would only make sense for the Mach E to be my commute car (>90 eMPG hwy) versus my Powerboost (only 20-22 MPG hwy). Then I have multiple Level2 options once there as my condo association is allowed to use the Kaiser chargers across the street overnight (SemaConnect $1.35/hr) or at work during the day (10c/kWh, limit 3 hrs). Occasionally, I would love to head to Santa Cruz (another 40mi each way) to visit my daughter at college and make it back to San Jose in one trip. Or at some points get all the way from Sacramento to Santa Cruz (170mi) without stopping.

This leads me to anxiety about REALISTIC range! We've ruled out GT and AWD (<270mi) to maximize range, and have eyes on Premium ER RWD (~300mi). I believe these figures assume ENTIRE BATTERY from 100% to 0% and therefore are not realistic unless you want to send it to an early grave (or sell before it's too late!) due to deep cycling/topping.

So my technical question is: Is the battery performance normalized from 0% to 100% so that every % is a matched linear increment? True battery IV curves are non-linear and I don't know how the algorithm reports the SoC% (true, linearized, useable only?). If it is already linearized then realistic range is easy to calculate for desired limits such as 25-75% (50% of range rating) or 20-80% (60% of range rating). But if at the top of the reported SoC% range the increments tick down faster, then by definition that middle (say 25-75%) band gets MORE than half of the total range rating, which would be fantastic.

I hope I'm making sense? This could make or break our decision (we're ordering when it opens up Aug15) on AWD vs RWD because we don't want to cut it too close. I don't want to limp into my garage at 15% as I'd prefer to roll in above 20% w/out ever having to make a stop.

As someone who pays 26c/kWh at the BEST of times (2 AM or so...) I can't even believe there's anywhere with energy so cheap in California :O

 

[mkhuffman]

That just seems impossible unless you are driving in traffic slowing you down below 75 MPH or going downhill. At 75 I'd imagine you get around 2.8 mi/kWh so your real range will be around 250 miles tops.

^^^ I agree with this. Traffic congestion makes a huge difference.

Once every week or two I drive to DC and spend the night. It is 143 miles one way. I set the cruise for 80 but for a lot of the trip I am in heavy traffic. So my efficiency goes way up compared to steady, 80 mph driving.

I am willing to bet the OP will not have freely flowing traffic for his entire 132 mile commute. So getting 3 mi/kWh is very possible, and probably better is likely especially if he stays close to the speed limit. I don't see efficiency that high, of course, but he is looking at a ER RWD, which is more efficient than my car.

Edit: the last time I did the 143 mile drive to DC, I arrived with 40% SoCD. That is in a GT and going 80 mph whenever I could. But with lots of traffic, of course.

 

[AZBill]

That just seems impossible unless you are driving in traffic slowing you down below 75 MPH or going downhill. At 75 I'd imagine you get around 2.8 mi/kWh so your real range will be around 250 miles tops.

My last trip Phoenix to Tucson I got 3.5mi/kwh at 75mph (the speed limit here in AZ), slightly up hill (+1000ft). The Route 1 is only RWD and has more efficient wheels/tires, it makes a real difference in range.

I have done Phoenix to Grand Canyon and got 3.1 mi/kwh or 270 miles, going 75mph up a 6000ft climb.

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