Qs about batteries for a VERY light car-- 580 lb w/o batteries
I have a British sports car from the 'microcar' era-- a 1959 Berkeley SE 328 (yes, the size of the orig. motor-- 328 cc; Google 'Berkeley 328' or 392 in google pics-- you'll note that it's very aerodynamic, an ideal small project. They came with an 18 hp 2-stroke motorcycle motor, and were only capable of about 65mph. This model weighed under 700 pounds from the factory, so, stripped of the ic motorcycle engine, the transmission and gas tank, my project will start at about 550 lb-- plus batteries, bms, and motor/controller. I obtained a Berk previously converted to electric in the late 90s for competition; it beat all comers in autocross, and won a 7-day EV road event one year. So I'm aiming to get it back on the road, but the old batteries and bms are long gone. I got the car with a new 144v Solectria AC motor (yeah, note: AC, not DC) and Solectria controller-- part of the purchase deal. My goals are moderate speed (v short burst to 65, a short cruise at 55-60, maybe 20 mi, or longer cruise at 45-50), moderate acceleration (no showing off), and a range of 60 or so, assuming its not running wide open -- more like 40 mph average for the trip. I feel there's no way could I load up this little car withlead-acids. In a note from L H in MN, L says he thinks that 60 mph in a Berkeley probably only takes 5 HP. 1 HP is roughly 1 KW. So the 144v pack needs to supply 5000w/144v = 35 amps. Peak power needed to accelerate and climb hills at moderate speeds will be about 3 times this or 100a at 144v. Roughly, he says, I'll probably use about 0.2 KWH per mile. A 20-mile range thus takes 0.2 x 20 = 4 KWH, and a 60-mile range takes 12 KWH at constant speed on level ground; double for hilly driving or frequent stop-n-go. As the KWH and pack voltage tell the needed amp-hour capacity of the pack, his estimate then calls for 12 KWH /144v = 83 amp-hours. So I feel OK about using 100 a-h cells-- and more might be hard to fit into so small a car. He notes that for a 144v pack, I'll need 45 cells. Each cell weighs 7.5 lbs, or 8 lbs with hardware, so I'll have a 45 x 8 = 360 lbs pack, plus BMS. Final weight with me driving: not much over 1000 lb! SO, my Qs: If this were your project and you were opting for lightweight batteries, what chemistry would you chose-- I gather there are two different Lithium chemistries (Li and Li-Fe, I guess- or suggest any other chemistry readers can steer me to-- which sounds unlikely). I'm prepared to put upwards of 5 grand into the batteries and batt. management. If lithium it is (which type?), then further: What Brand? I've heard a lot of bad things about Thundersky, and although I'm told CALB is better, one veteran of EVs has told me CALB is good for power, but not for range (not sure of the physics of that). So the big questions are: what chemistry, and what brand of battery seems to have a superior record? And THEN: does that brand also offer a batt. management system that is reliable? If not what BMS yould you buy? Any and all information and opinions welcome! Thanks, Chris in Northern VA -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20130902/f8d28f6b/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
