These URLs are about electric assist for bikes: you'll find various drive systems, from the minimalist to the bike that's on the verge of becoming an electric moped. The electric assist can make bike commuting a practical alternative for the not-so-athletic among us (that's me!). We'll also cover some ultra-lightweight EVs, which are not primarily human-powered. These are electric minicars, skateboards, scooters, etc. in which the primary usage mode is passive: the electric motor carries you along without your pedalling, pushing, rowing or whatever. But they are not traditional electrified cars.
When we think about bike activists and racers, the image that comes to most people's mind is the whippet-lean, nervy, agile 20-something-year-old male: all testosterone and muscle mass, clad in fetching high-tech costumery and strangely technical shoes (and a fierce scowl). But let's face it: people aren't all twenty-something, nor are we all equally athletic or energetic -- nor should we all have to be. Not everyone can make it up all their local hills, or spend all their time training so that one day they can!
And as Ken Kifer points out
Well, a major part of the problem is that they run the roads straight up the hills. Grades for a bike route uphill should not exceed 4 percent. Originally, auto roads wound around as they climbed the hills, but with more powerful engines, we are now just ignoring the grade. That creates a major problem for low-powered electric vehicles as well as for bicycles. Basically, we build a road network suitable only for cars and then say that cars are a necessity!
Many people think that rules out bike transport as a practical alternative for "the rest of us", but electric assisted bikes can make biking a practical local transit method for folks who are older than, or not quite so buff as, your average bike racer/triathlete. Trust me on this -- I'm old and fat and it works for me!
An EAV is an ultralight (2, 3, or 4 wheels) vehicle which is powered sometimes by human effort, other times assisted or wholly powered by an electrical motor drawing on batteries. The percentage of power derived from pedalling vs from the battery varies not only with the design, but with the rider's habits. You can make short lazy trips with no pedalling, or longer trips with lots of pedalling. An ULEV, as I said on the main page, is an ultralight vehicle which is intended for passive transport, i.e. you don't pedal.
When I say "ultralight" I of course refer to the vehicle before the batteries are installed :-) Any EAV is going to be heavy, heavy, heavy compared to a high-performance road bike or MTB. If you're going to have to carry it up 2 flights of stairs, think about that.
Another thing to think about is battery care. Both lead-acid and NiCad batteries have their quirks. Lead-acid packs should not be left in a discharged condition, whereas NiCads should be fully discharged before recharging. The most common source of disappointment with electric vehicles and toys is not taking proper care of the battery pack. So if you decide to use an EAV regularly, figure out how your battery charging regimen is going to fit in with your vehicle use pattern. Can you charge it as soon as you get to work? Can you charge it outdoors? Do you need to put more miles a day on it than you have recharging hours to top it up? Figure all this out before you invest!