John Ferrell earthlink.net> writes: > The cost of the Li batteries, their charging and maintenance are > likely to be the governing factor in the US. The battery pack alone > for an 11 pound model airplane is currently about $750 in the US. This > will yield about a 10 minute flight with a one hour recharge time. The > performance can exceed that of comparable alcohol fuel. I just did some reading and searching and was able to find the following: DD size cells (3.6V 35Ah) are a little under $40 each on: http://shopping.microbattery.com/s.nl/sc.2/category.636/mbcat.litcy/.f So a 2.5kWh battery (20 cells as above) would be about $800, without quantity rebate (I have good reason to believe that the price can be halved for reasonable quantity). This should be enough to give about 7 horse power peak (at 2C discharge = very conservative!), and run for at most an hour at half that spec (say 1.5 hp (~0.5C)). This should be enough to run a light (fiberglass etc) 'electric' car at maybe 25-35 km/h for two hours or ~50km. By scaling this up, for $4000 (200 cells) one would buy 25kWh of battery able to run 70 hp peak and 30+ hp for an hour at maybe 50km/h. That should convert your average not so small compact car (maybe as seen on CNN) into a lithium battery car for under $10k and provide enough range to drive to work and back for most short commutes (in town etc). The battery would be small and light enough that doubling its size (+$3000) would not be unthinkable. Nor would swapping it with a precharged one be unthinkable. 200 DD cells should weigh only about 40kg and be quite compact. If split into four banks anyone could change them by hand without lifting equipment. Some more imagined calculations: Assume two full charges (at night and while at work) are loaded and consumed per day = 50kWh per day. This would cost at 5 cents/kWh about $2.5/day. The battery life would be 1 year (~700 cycles), $4000/365 days about $11/day, plus power = $13.5/day. This for in town driving and commuting over a distance of about 2*50km = 100km/day. (the fiberglass car would only cost about $1.5/day). A small car can do 8-9l/100km or about a gallon per 50km, and that would be more than $6/100km at current prices (more outside the US where one pays well over $1/liter of fuel all the time, not just in times of crisis). So I would say that driving an electric vehicle cobbled together from parts bought at retail prices, would cost at most about 2 times as much than driving a gas powered vehicle costs now, and if the powers that be wake up and subsidise the lithium battery industry the way they tax and subsidise fuel, this may change rather fast. Also the initial investment is manageable for the 'garage guy' in most industrialised countries imho (I assume that the motor and controller cost is split over several years of use - can be ten or more - and thus contributes relatively little to the daily cost). There are several websites made by people who already did this (convert commercial cars to electric). But what would the legal status of such 'cobblings' be ? Is there an 'experimental vehicle' class ? Peter -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist