John, I think that would be a lot of fun to experiment with. Some of your numbers are a bit off. For example, 100 whrs/mile is on the light side, unless you are riding less than 40 mph most of the time, or have a light setup. I'd figure more like 120 for 45 mph avg. riding.
And, as for the generator output, if it's going into your charger, than the charger will be about 85% efficient. So, a 3500 watt generator running for 1/2 hour through your charger could put 1487.5 whrs back into the battery pack, or add about 12.4 miles. Not bad. It'd be nice if the generator only kicks on at 80% DOD, so it wouldn't be used often, but than it can't replace charge fast enough to add much extra range. Here's an idea, I have for comparison. Couldn't you just buy a 125-250cc maxi scooter which gets 70-80 mpg? You could somehow mount a swingarm PM motor, and some batteries in saddle bags for a short electric range. After the electricity is used up, than you will get 70-80 mpg for as fast and as far as you like. The electric range could be used for those routine home/work/grocerty store trips every day, and if you need to go further, than just start the ICE. Actually I'm considering doing a "conversion" on a car like this, while keeping all of the stock ICE components. Anway, sorry this is kind of OT. Regards, Andrew in NM On Tue, Apr 1, 2008 at 9:56 PM, John Fisher <[EMAIL PROTECTED]> wrote: > Andrew I want to challenge this, but in a nice way, in order to get to a > better answer. > > so correct my estimates where wrong: > > my assumptions: > a light vehicle in the motorcycle class > a driving cycle that includes moderate hills, stop and go, some flat > sections of 40-50 mph, but no mountain passes or freeways > a goal for greeness that states 75 mpg is pretty darn good. > about an hour of range, say 30 miles > ability to limp home on the genset alone > try to cut battery pack roughly in half by using genset > > so, the generator would start running when the pack is down to some > chargeable figure like 80% > say ithe vehicle uses 100 Whrs/mile at 72V, thats only 3 Kwh to do 30 > miles > did I do this right? > I checked the evalbum and folks seem to have 30-60 amphours in the lead > packs- on the high side, say 30 usable AH at 72 V would be something > like 2.1 Kwh > so lets say 4Kwh to do the 30 mile loop. > > if i did this calc right, a 3Kw generator ought to be able to nearly > double your range, and a 3kw generator would be able to use a 5 or 6 hp > ICE. > commercial 3500 watt gensets use something like a half-gallon per hour I > believe ( check this) with pretty darn crude engines. > > Now I know you can't fit a standard 3500 watt generator on your bike, > but stick with me. I have more space, and that generator is lazily > packaged. The Honda or Yamaha ones are not only far better, they are > much smaller ( but pricey I grant). So if I did the math right a 3Kw > genset would be practical. > > whaddya think? > > J > > > > Andrew Wowk wrote: > > The most practical application for this (120v AC generator to charger on > > board) is as an emergency range extender in my opinion. ... > > > > As a parallel hybrid (using the generator regularly), this doesn't > really > > make much sense. That's because, it'll require a very large and > expensive > > generator to help much. > >
