How much "extra" range should an EV have?

@charlesoverbeck Yes, if you don't periodically discharge Lithium ION batteries down to 0% the Battery Management Unit can over time start losing capacity TEMPORARILY.

For example, when my own 7.5-year-old 26k-mile BEV currently shows 11% on its gauge, its OBD shows 18%, & with MY car that 18% is still usable capacity, with the car driving until OBD hits 0%, well past 0% on the car's gauge.

Also, the BMS can be reset by taking the car to 0% on OBD by drive until OBD is 1%, then parking by a charger with everything turned on until the motor shuts itself off.

@jesthorbjorn Yes, from what I've read at BatteryUniversity.com & PushEVs.com going to 0% is bad, however every EV's software prevents that.

Buffer sizes differ though, as they also do at the top end. For example my own BEV charges to 4.1V even though 100% is 4.2V, & it shuts off the motor so you can't drive it below 3.1V even though 0% is really 3.0V

Those 0.1V buffers at each end may not seem like much, until you notice that 1.0V is the ENTIRE usable range from "0%" to "100%" on the car's gauge. Apparently it's not linear, & 4.1V is about 85%, & that's as high as it allows it to be charged.

Also, while it IS apparently better to take a Li-ion down to 20% than it is to take it up to 80%, going to 0% (the OEM buffer limit) is much worse than taking it to 85 or 90%.

In my opinion, range for three hours of driving is enough for an EV, as long as there are enough chargers in your area. I have a 12 mile round trip commute to work. My wife has a 40 mile round trip commute to work. An average week, we go no more than 125 miles a day. In a month we may have one day with more than 200 miles to travel. In a year we may have a day with 500 miles of travel. I don't think I've ever travelled more than 1000 miles in a day by car.

I've reserved the 400 mile version, but would probably have been just fine with the 250 mile version. Unless we forget to charge, I don't think we'll make more than one trip a year where we'll have to charge on the way, and even if we did, it wouldn't be much of a problem. We have a DCFC about every 50 miles along major roads where I live. I have to go more than 500 miles from home to get to a location remote enough to be more than 100 miles between DCFC:s.

I'm usually in no hurry, so I don't mind stopping to charge somewhere along the way on long trips.

120 miles round trip, 60 miles one way. The 400 mile aptera will cover you comfortably with range to spare in any condition.

@Vince La Luz Ya, no kidding: On another thread I just did a double-take on my own example of charging speed. From just a standard wall outlet Aptera will only take 3 hours to recharge a US-daily-avg 40 mile commute which takes EIGHT hours to recharge in any other EV.

Whoa! Even with only one sub-standard 15A garage outlet, you & your spouse could arrive home at 6pm, plug in the Aptera, then at 9pm switch the plug to the Tesla, & by around 5am both cars are ready for another daily 40 miles!

@Vince La Luz I gave a bad example. Here's a better one:

I drove my friend's hot dark charcoal 500e in 113F for an hour on the freeway (high heat current), then a few miles in stop-&-go (low cooling airflow), parked in baking noon sun & plugged straight into L2. The fan came on for a minute, & then went silent. It didn't even need to activate the A/C (which can chill the coolant below ambient).

Granted, that's only L2, but I've heard Teslas making more noise than that on L2 even when it's 20 degrees cooler. My point is that just because Teslas crank up their cooling systems for half an hour of 72kW or whatever doesn't mean an Aptera can't handle its own 50kW limit for 12 minutes to gain the same amount of range. Especially if they use the A/C system to dissipate some of the heat.

@Vince La Luz Teslas may be a rare case. I too have heard them making noise, even on L2, presumably cooling. Yet when I plug my Fiat in, at most only the fan makes a bit of noise, & never for more then a minute before cycling either off or so low that it's silent even with the hood open.

I suspect that every slight variation in battery chemistry & construction makes a difference in how much heat they create when charging:

- Tesla batteries may be optimized for the best acceleration & range for their size & weight, at the expense of cooling requirements.

- My Fiat battery seems to produce very little heat, staying no more than 2 degrees above ambient just with coolant flowing through the radiator (water pump running) & no fan, even when it's 90F out.

@Ken Kobayashi "a car whose EPA range is 3x greater than your normal daily use" sounds perfect. It would have about 120 miles range for the average American.

My own drive is a bit shorter than that, but, I'd like to order a 125-mile Aptera.

The half-size battery would also make it lighter, for even better efficiency, braking, cornering, & acceleration 😈.

I am NOT kidding. I love efficiency & hate waste. I don't want to pay for six times as much battery as I need, & then have to drag it around with me every single day, just to avoid renting or flying for long trips. 3x what I need would be quite sufficient. I've gone over 5.5 years now with that & it's fine even without DC charging or even home L2.

My opinion: Worst-case usage scenario is forgetting to plug it in one day, and both days hot or cold enough to require AC/heat full blast. Which means the car should have enough range to cover 2 days of normal use, even with AC/heat on. So I think a car whose EPA range is 3x greater than your normal daily use should do it. And don't pretend you'll never forget to plug it in. It's always possible to get distracted when you get home - talking to family, unloading stuff from your car, etc.

@bcjankowitz Aptera's sustained discharge rate is approximated on line 16 of this chart (click here).

Having been reminded of that chart, I see that our estimates of 5-times-power for a crazy 25% grade 😲 should be more like 34.5kW, but that's still WELL below the no-cooling-airflow limit of charging 50kW DC.

Climbing that hill even with a 60mph tailwind should be fine.

The chart's 6.9kW x 5 = 34.5kW.

Thx

I guess we have a good testing location with all the CA traffic for stop and go?

Here in southern AZ I can provide them , outside my door:

👉heat and

👉high speed interstates

While offering an EV charger in the garage to top off their range.

👉Need mountains? We got them too

( only ~10,000’)

So…“Come on down Aptera !”😉

I an sure they have a plan

The skin cooling has issues when stopped (no fan) and should work quite well at highway speeds. With the light weight and high efficiency climbing steep grades at high speeds on the highway should be no problem. Heat production in the motors and batteries should be 10-20 times less than an ICE car. The main problem with the skin cooling will be in situations where ICE cars run their fans (stop and go traffic on very hot days) and that will affect the HVAC more than the motors.

this begs the question:

What is the sustained discharge rate of the Aptera?

@993cc That's right: 0.500kWh/mi x 60mi/h = 30kW discharge rate (just no "per hour" at the end). That's based on Tesla using 5 times the energy climbing that hill.

However this may lower Aptera's usage: Power to climb a hill is directly proportional to mass. Half the weight, half the engergy/heat. Same goes for power to slow the descent, as in heat from regen current.

Aptera weighs 1800-2200Lb.

Tesla 3 weighs about 3552Lb (1.61 to 1.97 TIMES as much).

I do agree that the Aptera needs t be able to handle extremes.

My middle daughter is currently in Montana and in the past was bouncing between Alaska and Wyoming. One of the big reasons I initially was drawn to the Aptera was that the range would bridge the lack of charging stations in Montana but if its incapable of handling the terrain that's a huge strike against it. The mountain pass between Idaho and Wyoming is not Pikes Peak but needs to be navigable.

This is something that I'd like to have quantified by Aptera cause this is a huge show stopper for me if the Aptera can't handle.

I agree that the skin cooling might be the limiting factor for charge and discharge rates. I'm a bit curious to know about what conditions or situations that drove the high drain numbers you encountered? I currently have a Kona EV and have only paid attention to the average usage of about 3.9 mi/KWh and I'm definitely concerned too. The average numbers may suffice because of the time it takes for the drain to cause heat but only MAY.

IF with a 600 or 1,000 mile Aptera you're not doing top ups while driving because after 450 miles you're depleted yourself, even though the car isn't:

You stop & plug into 50kW DC & in under an hour your day's drive is fully replenished while you have a relaxing meal & you could even keep driving for a while before stopping to sleep.

For top-ups which you may want in a 250 to 400 mile Aptera, fast charging takes about 21 to 34 minutes respectively to go from 10% to 80%. It can never take two hours, since it would be fully charged from dead way before that.

@Joshua Rosen I agree, up until your comment about fast charging: Aptera's 50kW DC rate is equivalent to about 125kW for any other EV, since it adds about 500 miles per hour (8.33 miles per MINUTE).

As you note, "with the Aptera 600 mile version you shouldn't have to fast charge at all", so there's no reason to "fix the fast charging speed on the larger battery".

10% to 80% on the 400-mile will take about 34 minutes. I don't consider that "ridiculously long". About 21 minutes for the 250-mile.

Update to earlier post to clarify what I'm hearing so far...

Range losses from design specs for real daily use:

- 40% less than spec to stay within 20-80% state-of-charge for battery longevity

- 50% less than spec to stay within 30-80% state-of-charge for MAXIMUM battery longevity

Seasonal:

- up to 40% for cold temps and resistive heating (until 2nd production model includes heat pump)

- up to 10% for lots of rain

- High range hit for steep assents, minimized if combined with comparable descents

- Negligible (?) hit for A/C, especially vs. windows down for this design?

Much thanks for everyone's inputs. Paints a clearer picture of what's realistic from each range spec

The other factor that I don't see others have mentioned is how much you want to constrain your SOC (state of charge) range of use in order to extend the life of your traction battery.

While manufacturers seem to be getting away from this, early assertions of EV range were based on going from 100% to 0% SOC; a sure way to kill a battery way before its time. It is not clear where Aptera is in this regard, but I'm inclined to think that they are claiming the extreme value.😐 Of course those are pretty huge range values so...

My understanding is that a standard charge cycle for cycle life testing is from 100% to 20%, and then back to 100%. If the warranted cycle life of the battery pack is good enough for you, then you will want to assume 20% less range than the absolute maximum range that may be asserted and use that for your practical range.

Even then, more than 80% of that standard cycle life battery wear occurs between 100 and 80% SOC and also between 20 and 30% SOC so theoretically you could coax a battery pack into lasting something like 5 times as many charge cycles as advertised if you kept that SOC in that 50% (30%-80%) mid-range.

The 40% hit for a resistance heater is good to know. That would be a fringe concern for many, but a real concern especially where this will be someone's only ride...

Range losses are roughly:

40% for lots of heat

10% for lots of rain

High hit for steep assents, minimized if combined with comparable descents

Negligible (?) hit for A/C, especially vs. windows down for this design?

You lose about 10-20% of the range in the rain, 40% in the winter if there is a resistance heater, less if it has a heat pump (they hope to have a heat pump but I wouldn't be surprised if the early vehicles have a resistance heater. Climbing a mountain uses a tremendous amount of energy on the way up but if the regen is strong you will get a lot of that back on the way down so the range hit for altitude changes is much smaller than you would guess but you do have to figure in the energy to get to the top of the mountain. For daily driving assume that you'll charge to 80% but for long trips make that 90%, 100% should only be used if there is no alternative. These are Tesla rules because they expose most of the battery to the user. Audi hides huge top and bottom buffers so you can charge an Audi to 100% because that's equivalent to 90% on a Tesla. How much buffer Aptera will use is an unknown at this point but I'd guess they will be much more Tesla like than Audi like.

If you want to see what can happen on a steep mountain I've attached a picture of my energy screen from last Saturday. I went over the Lincoln Gap in Vermont. The Lincoln Gap is supposed to be the steepest road in America, 25 degree grade with lots of hairpin turns. It's a lot of fun in an EV because regen braking puts the energy back into the battery rather then setting your brakes on fire as you would with an ICEV.

Everyone has their own needs..... I never owned an EV, I read the articles out there on the Mfg posted EPA ranges and independent ( like Edmonds) testing on EV ranges, joined EV clubs to pick the brains of those EV experiences.... and "Expect" because of my range hit choice (AWD, 60 kWH and Off Road kit (although still not sure what all is in that yet) that 40 k WH would be a sweet spot( I believe Steve or Chris mention that might be the most common size ordered?), but I too have high speed interstates and some elevation ahead planned with cross country treks. I never drive more than 500 miles a day now, so.. 60kWH seems like "my EV range choice sweet spot". Free solar charge range is "icing on the cake".

This might all make better sense to me when Aptera gets at least to their Gamma development vehicles and maybe validates some of the above.

So I said to myself...SELF.... Stay Calm.... No commitment until order time. Reservations are changeable and refundable. There will be many production vehicles on the road before yours starts. Isn't there a 1000 mi/ 7day return deal too? SWEET!

I might rent an EV to get some experience as my son's EV is thousands of miles away. But he is a great resource too, with his now third EV experiences!