abasile said:
GRA said:
The other approach, which GM is apparently using in the Bolt (and I've been somewhat surprised no one else has yet) is to always leave some space in the battery for regen, above the maximum charge from the wall.
That won't really solve the mountain descent problem, as we see regen limitations due to the cold and/or long descents even when the battery is well below full charge, even at 50% charge and below.
It will, however, enable everyday drivers to charge to "full" without worrying about a lack of regen or leaving the battery at a high state of charge. A more transparent way to accomplish this is to charge to 80% or 90% by default, and require the driver to enable a "range mode" to access the top of the battery. Many will prefer the more transparent approach (which Tesla Motors employs, I believe).
Delayed reply, due to being up in the Yosemite backcountry from Saturday evening until yesterday on an annual trip (since 1980): http://www.sfgate.com/travel/article/Yosemite-Cozy-Ostrander-Hut-worth-the-work-3229654.php#photo-2372264
https://www.google.com/search?q=ostrander+hut+images&rlz=1CASMAD_enUS677US677&biw=1280&bih=689&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwie8fjWw83KAhVI6GMKHb_qBl8QsAQIGw#imgrc=QLGGpG_ia2DDlM%3A
Done correctly, i.e. with battery heating, I think it will handle cold weather regen limitations (there shouldn't be any - you should always be able to charge to exactly the same capacity in kWh, controlled by the BMS) and mountain descents. I think that issue is primarily restricted to cars like the LEAF that lack battery heating.
You need to have enough extra capacity on tap to handle some or all mountain descents; how much is appropriate will likely be a source of differentiation between manufacturers and/or models, as the more excess capacity you hold for regen, the more expensive the battery. The people who live in Flatland won't need as much as those who regularly make the descent from Lake Tahoe to the Bay Area, or Vail to Denver. Maybe it will be an option, sort of like a tow package. Those who know they'll need it will choose to pay extra.
Re the use of 'range charge', I don't think that's the way to go for the mass market, which is always lowest common denominator. It's too geeky, and requires knowledge of which conditions are appropriate for its use. Considering that even here, where the average person is far more interested in the technical details, we regularly get questions from both newbies and even some long-time members that could easily be answered by consulting the owner's manual, it's pretty clear that the average person just isn't willing to devote any time/energy to learning specific operating information.
IMO, anything intended for mass market acceptance has to be usable by the brain-dead, requiring the absolute minimum of special knowledge. I was flabbergasted to learn that a friend of mine, who grew up driving backhoes and concrete mixers with manual transmissions, had no idea that the '3', '2' and '1' settings on the transmission selector in his 4Runner could be used to provide compression braking for hill descents - he'd never used anything other than 'D'. I expect that 'L' and the extra regen button in the 2016 Volt and similar cars would go largely unused by the mass market, at least until a whole generation of users has grown up with them. This argues for one-pedal implementation (all regen on the accelerator, brake pedal only for friction brakes) ala' Tesla/BMW, but I think the feel of that is just too weird, for now at least, for mass market customers who typically make their buying decision based only on a short test drive; it will turn them off. Those of us who prefer more control over the car's functions will want to be given as many driver-customizable options as possible (at a minimum, I want several levels of regen varying from none to max, akin to the gears in my manual transmission).
So, I think that we need the options for those of us who are more interested in getting the most out of our vehicles, but as much of the full functionality as possible should be included without any need to change settings or learn anything more than how to turn the car on, make it move forwards or backwards, and how to plug it in.
