On Tue, Feb 15, 2011 at 8:59 PM, Isaac Marino Bavaresco wrote: > Em 15/2/2011 18:04, Olin Lathrop escreveu: >> Yigit Turgut wrote: >>> If you assume the start point is at sea level then you >>> should be right with your numbers 4 - 5 km's. >> OK, let's take this at face value. =A0Let's say the car weighed about 1 = ton, >> which is light for a car. =A0That's 2000 pounds, or about 9000 Newtons. = =A0If >> you take a 9000N car on a trip and it ends up 5000m higher at the end, 4= 5MJ >> had to have been expended somewhere somehow. =A0This has nothing to do w= ith >> how curvey or not the path was, how long it took, or what exactly propel= led >> the car. =A0This is simply looking at resulting potential energy alone. >> >> Now let's look at a car battery. =A0Let's be generous and say it is rate= d for >> 100 A-h, which means it can put out 100A at 12V for 3600 seconds. =A0Tha= t's >> 4.3MJ, or less than 1/10 of the absolute minimum it would take to move t= he >> car up 5000m. =A04 such batteries simply can't do that, and that's assum= ing >> the entire energy of the battery can be converted to potential energy of= the >> car. =A0In reality there will be wind resistance (you said average speed= was >> about 80km/h =3D 50 miles/h, so wind resistance is a factor), other sour= ces of >> friction, and of course inefficiency in converting the battery energy to >> motion. >> >> Clearly something is wrong somewhere. > > > The site says that the 4 batteries are 150Ah for a total of 25.92MJ, > which is more than half the necessary energy. But still not enough. It also says the car is only 470kg, so 4600N, hence only 23MJ required in potential energy. So providing you can extract all that energy from the batteries with 100% efficient motors, and not too many other losses it is possible ;) The bigger problem is that the claim is a minimum speed of 70km/h - even if it was all done at that speed it would take 8.57 minutes or 514 seconds to cover the 10km, hence 44kW required power just against gravity, yet only 1.6kW of motors. Of course if we look at motor power, then consider that for a bicycle, 400W will get you close to 50km/h. Given almost all the power there is against wind resistance and that power required to overcome wind resistance goes with the cube of the speed, then 1600W would only get you close to 80km/h for a bicycle frontal area/Cd - now that car would appear to have a lot more than a bicycle worth of frontal area. Chris --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .