Tail Lights And Range

[scottsim]

Lou,

I would think there is plenty of flexibility to make the 24mi commute...mine very similar, over Mt Konocti...there also may be options for a slightly larger battery pack from the hints seen here....

S

[KarenRei]

Originally Posted by Louv

I have a 24 mile drive, with a 2000 foot elevation change to get home from work.

I'm confused... why is this a problem? It has a 100 mile range at 55mph and you're worried about 48 miles with a zero net altitude change (up and down in-between)? Even if you drove 80mph the whole way, I doubt that'd be a problem at all. And this is assuming you can't charge at work...

[Louv]

Originally Posted by KarenRei

I'm confused... why is this a problem? It has a 100 mile range at 55mph and you're worried about 48 miles with a zero net altitude change (up and down in-between)? Even if you drove 80mph the whole way, I doubt that'd be a problem at all. And this is assuming you can't charge at work...

I haven't done the math, but it seems to be getting closer and closer to the edge.

- 2000 ft climb UP to the house at the end of the day. Not up and over, just up. Down to get to work... which will certainly help, but at that point I'm already charged up, so regen braking won't help.

- "up to 100 miles". When the batteries are new. When the batteries have a full charge. If I recharge every night, in a year or two the batteries will probably be at 80 percent original capacity. 500 charge cycles for LiIon = 80% capacity, if they were treated kindly during charging. What are the specs on the Bat Technology for the 'Tera?

- No, I probably won't be able to recharge at work. (I bet that at my last company, I'd have gotten an outside charger... my last CEO has recently been called the Neil Armstrong of Aptera... or something like that...)

- If I _just_ drive to and from work, fine, no problem. But what if I drive to lunch (I don't work for Google, so I have to go out and find my own food at lunch). What if I need to run an errand across town?

- I don't drive 55. It's rude if the rest of traffic is going 65-75. So, what's the range at 75 miles?

I'm not saying I can't live within the "up-to-100 mile" constraints, I'm just saying that if the vehicle becomes too much of a stress factor (i.e. constantly worrying if I can make it home at night) then I'll just drive a car instead. Or ride a motorcycle (one with 2 wheels! :-)

The first time the Aptera can't get me home after a day at work, and an errand or two, it gets sold.

[speculawyer]

Originally Posted by KarenRei

I just got a bit of information passed on to me, indirectly, from Aptera:

1) The 100 mile range is at 55 mph.

I was right.

[KarenRei]

- 2000 ft climb UP to the house at the end of the day. Not up and over, just up. Down to get to work... which will certainly help, but at that point I'm already charged up, so regen braking won't help.

Sure it will. 2000 feet is a potential energy change of something like 1 1/2 kWh. 24 miles of driving on flatland would be in the ballpark of 3kWh of energy consumption. So the other forces are greater. Now, I assume it's not a smooth even slope -- there will be some up and some down -- but overall, you should still arrive at work down some power. On the way back, you burn, again, in the ballpark of 3kWh, plus 1 1/2 kWh for the altitude change. Under half a pack for the return trip.

- "up to 100 miles". When the batteries are new. When the batteries have a full charge. If I recharge every night, in a year or two the batteries will probably be at 80 percent original capacity. 500 charge cycles for LiIon = 80% capacity, if they were treated kindly during charging.

Oh heavens no. You're thinking of traditional li-ion -- cell phone batteries, laptop batteries and such. Laptop batteries not even babied the way Tesla babies theirs (if you treat laptop batteries like they're each a delicate flower rather than just cramming them between a hot CPU and someone's lap and charging them to 100% every time, you can get 5 years out of them for 80% charge retention). But these are not laptop batteries, not an LiCoO2 cathode and a graphite anode. These are lithium iron phosphate -- LiP. The big downside to LiPs is that you have to sacrifice a lot of energy density (~100-110Wh/kg versus 160-180Wh/kg. In exchange, however, you get *far* superior longevity, faster charge/discharge capability, and much greater safety. The industry seems to expect at *least* 10 years of normal usage to 80% out of LiP packs.

- I don't drive 55. It's rude if the rest of traffic is going 65-75. So, what's the range at 75 miles?

We don't have a number from the company, but probably in the vicinity of 60 to 65mi. If you drive 75 mph the *whole way* -- i.e., never any side streets or anything, but freeway your door to your company's door. Also, the faster you go, the less altitude changes matter, since overcoming gravitational potential energy becomes a smaller percentage of your energy burn. Gravity is a fixed cost that doesn't change as your speed-related consumption changes.

I'm not saying I can't live within the "up-to-100 mile" constraints, I'm just saying that if the vehicle becomes too much of a stress factor (i.e. constantly worrying if I can make it home at night) then I'll just drive a car instead. Or ride a motorcycle (one with 2 wheels! :-)

And this is why Aptera needs to have an accurate range-simulating webapp Overall, I think you have the right feeling about how range decreases with speed, but I think you're way overestimating the impacts of gravity and aging. If this were PbA, you'd have a better argument against gravity due to Peukert's Law (the faster you draw current from PbA, the less total power you can draw), but that really doesn't apply to li-ion in any significant way. And they regen quite efficiently, too. Regen boosts the Tesla Roadster's range by about 40% in the city. I don't have their blog entry handy, but they once mentioned its regen efficiency... I think it was upper 60s/lower 70s *round trip* (i.e., counting the losses in propelling the vehicle, then the regen losses)

[Apt3448]

That is not the info I got tonight, see my post at
http://apteraforum.com/showthread.php?t=2224
-100 on the free way, with airco on, etc, more like 120 at 55.

[KarenRei]

Then we have conflicting sources. I'll try to get this cleared up.

[Apt3448]

Many of us were there and took a gazzilion pix. Anthony had a whole list of questions and interrogated Paul Wilbur on video, i'm sure he will post all that, with more answers and details, it was a great night. I think he got Paul Wilbur on tape about the range, too.
Oh, yes the windows will go down somehow, but when asked if they would open completely I got a non-committal response (Seems they are still working on that).

[Louv]

Thanks Karen.

OK, my comfort zone is returning.

me-> <-you

Thanks for the edumacation! I guess I stay in line!

[KarenRei]

Updates: Again, the person I'm talking to passed me along things that I'm allowed to mention:

1) "There will be a single battery option in the all electric."
2) Concerning range, it seems what Apt3448 was told is closer to accurate... I need to clarify still what I'm allowed to say here.