The most efficient EV APU I know of was the "Long Ranger" trailer Alan Cocconi built for his Honda Civic hatchback EV about 2 decades ago. He used a (Kawasaki?) motorcycle engine.
http://www.evdl.org/docs/acp_lr.pdf I'm not sure the gadget advertised in the flyer linked above is the same as the one Cocconi actually used to drive his Honda EV all over the US. It says it generates 9kW and "extend[s the] range by 200 miles per 5 gallon tank of fuel." That would be 40mpg, but I recall reading that the one Cocconi actually used with his Honda, which AFAIK actually could keep up with the EV's energy use on the highway, got a real world highway mpg of 32. For direct comparison, a similar Honda Civic VX or HF hatchback of about the same vintage got real world highway mpg in the 48-56 range. I don't think I ever read anything about exhaust emissions from Cocconi's APU. Anyone know how regulated motorcycle emissions were in the mid-1990s? Cocconi was (presumably still is) a genius engineer. I don't know about your engineering background, but I know for sure that I personally could never cook up something even that efficient and reliable in my garage. Apparently building an APU isn't quite as simple as just chucking a genset in the back and plugging your EV's charger into it. We've had quite a few discussions of fueled APUs on the EVDL over the years, and I recall reading reports of burned-out gensets, chargers, even controllers. Be careful. Honestly, I think you'll get better results overall by just keeping an ICEV in the garage for long trips -- or renting one when you need it. Or you could just buy yourself a Chevrolet Volt. Be aware that the Volt's mpg in "charge sustaining" mode is decent but not all that impressive. EPA says 37mpg, and owners seem to get around 34-35. But if you're in it for the technical challenge, I guarantee that building and integrating your own fueled APU will give you plenty of that! David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)