Thinking about road trips where we often sleep at night, suppose we could charge a portable pack in the room where we sleep? Then plug it into the Aptera in the morning to provide some extra milage during the day. What would be a good weight/power balance?
I think the portable carry-on battery would need to be 50 lbs. (22 kg) or less so it can be easily handled. I did what you suggest with a battery assist trike I used for my commute years ago. Had two 25 lb. lead acid batteries that I lugged into my office during the day after my morning commute. I needed fresh batteries for my 20 mile ride home as most of it was up steep hills where I lived in Seattle.
I was thinking about that for daily Aptera use by people with no home plug, such as apartments with street or lot parking. Aptera would only need 40Lb of battery to take it the US average 40-mile daily drive.
40 miles times 10Lb/kWh, divided by 10mi/kWh. (all from their latest specs)
I have been reading the Q&A on the Aptera Wefunder site. Just saw this topic addressed by Chris Anthony. Here is the actual text in the Q&A as it is about 10 pages deep:
Gary OLIVER
Sep 11 2019
Can you make the battery pack behind the seat into a "Suitcase" I can bring in to my apartment (or someone else's) and charge overnight. How much range could you fit in such a "suitcase" size removable battery pack.
Chris Anthony CEO FOUNDER Sep 11 2019 Interesting idea Gary. Though it wouldn't be the module behind the seats as that is actually under the vehicle and would be hard to access. And there has been some ideas bounced around the EV world for this. Mostly, the ideas describe a small battery pack that you can carry around as you've suggested. With a 2KWh battery "briefcase" you could get 20 miles of charge back into the Aptera. Though, it would probably be easier to stop for lunch at a place with EV charging to top off when needed. The Aptera should have plenty of range for most but in special circumstances a battery "briefcase" might make good sense. Thanks!
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The back seat is folded forward. The battery is pulled out of the back seat via rails, the battery has fold-out wheels and a pull-out handle for better transport, the battery has a socket for connection to the household power supply. Due to the high weight, it would be useful if only half a battery module can be removed.
I personally, don't see much use in a removable portion of the battery. Only small scooter currently use that technology. What one doesn't realize is the complexity of the thermo-regulation system. Tesla uses glycol and BMW uses 1234 air conditioning refrigerant. One also would need a BMS system to balance out the cells from the new recharged pack to the rest of the vehicles battery. The emergency portable generators (batteries) that are pictured above are not meant to fully charge a car, but to give it several mile range to get to a charge station. It also puts energy evenly into all battery cells in a balanced fashion. Of course the thermo-regualtion is intact. Just my two-cents, but it's open for discussion.
The "much use" is for the great many people with no plug where they park at home or work.
Aptera's extreme efficiency which has now allowed solar to be viable, also now makes a plug-in module viable for daily use. Kind of like a small scooter, since its power use is not much more than that. The convection cooling which Aptera is considering would be virtually mandatory to make it practical with no coolant liquid.
Yes, Aptera's solar charging is sufficient IF your commute is short enough AND your assigned parking isn't underground AND it isn't shaded AND it's not too cloudy AND you don't live too far north.
Yes, IF you have time you can stop at a public charger IF there's one currently available near your route.
Someone suggested it SHOULD be required for every parking space everywhere to have a 120V outlet, but that would take a while to implement.
@kiteboarder. I am curious on how you are planning to cool this portable battery by convection if the car has no coolant or air vents? They are talking about cooling the car through the shell of the car and utilizing its vast surface area. But coolant whether it be ducted air or liquid would need to be circulated between the battery and the car surface. I am curious how you would balance the portable battery with the rest of the battery pack? Not disagreeing with you...just trying to understand better.
Heat shouldn't be an issue for a portable pack, with A/C at home/work: Even with 7-year-old technology, my EV's batteries generate very little heat even sealed in a case, doing a full recharge in only 4 hours.
A portable pack would only generate about half as much heat for a full recharge in 8 hours of work or sleep.
I, too, am a little bit curious how THEY are planning to "just convection cool to save weight." in the car, although eGolf apparently does that with no significant degradation. What gives non-liquid cooling a bad reputation are phones & laptops which not only have NO cooling, but also have degradation-inducing small buffers at their top & bottom charge limits AND are much more likely to have harsher full discharge-to-dead cycles.
Reportedly all those factors also apply to the 1st-gen Leaf. Subsequent higher-capacity models got increasingly bigger buffers & shallower daily discharge but still apparently sealed in a heat-retaining case.
I believe the issue with imbalance is mostly that it reduces pack lifespan, much like rapid charging, or driving/braking harder. So it's a user choice, but it's nice to HAVE the option of a portable pack, much like it's nice to have the option of high-current charging, acceleration & regen. Still, it might be possible to make the cells balance while driving, maybe by taking motive power from higher cells, & putting regen power into lower ones.
My Fiat BEV's pack only balances when charged to 100.0%. Some after-market home L2s stop short of that on some Fiats, yet one user with that setup just reported a slight issue after over a year.
Or, solving both issues at once: Portable packs could BE "portable generators (batteries) that are pictured above ... to give it several mile range to get to" home/work & back.
Keep in mind that this is a much more viable option in an Aptera since it gets 60% more miles from the same amount of power, compared to any current EV.