Hello, my first comment I think, hope I do it right! On Solar, some things need clarifying:
1. Area and angle of car-mounted collectors. Yes, at 90 degrees to sun is best, but at 45 degrees you will still get near 70% energy. That is perhaps a useful cut-off point to avoid expense and weight (and drag?) of panels with low output. I like to use square meters which give about 11 square feet per square meter. A small car we are designing has about 1.5 square meters of usable collector mounting, maximum 2 square meters or 22 square feet. 2. There is NOT no energy on vertical panels, as there is always indirect radiation. Sometimes this is the major solar energy available (England in winter....) I studied this one time, don't remember the exact details but they are available. But it is lower. 3. If the solar panels create ANY appreciable drag chances are high they will add more to your daily power consumption than they give. Dumb idea. 4. Maximum solar energy is considered to be about one kilowatt per square meter at noon. Affordable panels appear to be near 20% efficiency. So we can get about 200 watts per hour of full sun per square meter. Different areas have solar radiations than can be rated in equivalent noon-time hours of sun per day. For example here in Costa Rica it is near 5 hours equivalent per day year round. So a panel that can put out about 200 watts per square meter will put out about 200 watts x 5 hours = 1000 watt hours per day. If you can get 2 square meters on your car you can have 2 kilowatt hours per day to charge your batteries. 4. I REPEAT, to CHARGE YOUR BATTERIES. Having batteries on board and unless you drive your car ALL day long (!) it is silly to calculate how fast you can go ONLY from the power from the cells at the moment. Store that power! 6. Lets use a Nissan Leaf as an example. IF we say a usable 80 miles per charge for the 24 kwh pack to 80% discharge, then we are using about 20 kwh to go 80 miles. That is about 250 watt hours per mile. If we can get the above 2 kilowatt hours per day (optimistic because I did not include battery losses) then you will get about 8 miles per day of "free" driving from the solar panels. If you can have a lighter and smaller car maybe you can get 175 watt hours per mile? That would give 11.4 miles. Or if 150 watt hours then 13.3 miles. 7. So it would seem that you can get maybe an average of eight to twelve miles per day from roof-mounted solar panels. Do the math to see if it is worth the effort and expense. It likely will be only in some special cases. BUT if your trips are short, commercial power not reliable, and you can park it in the sun..... it could be a very satisfying experience. Jesse Blenn -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150330/447795ae/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)
