Glossary
Electric vehicle terms
file: REDSTICK/car/glossary_ev.htmlEquations
Energy = Force x Distance // ref/link: FxDequalsE.html Force = Mass x Acceleration HP(force_lbs,v_mph) = force_lbs x v_mph / 375 //brant pg 152 top watts(force_lbs,v_mph) = force_lbs x v_mph x 1.99 // 1.99=745.7w/hp / 375 HP(torque_ft_lbs,rpm) = torque_ft_lbs x rpm / 5252 Joules(force_lbs, miles) = // energy = (force_lbs * 4.448) x (miles x 1609 m/mile) = (N) x ( meters ) // force times distance. == force_lbs x miles x (1609/4.448=7157) rpmWheel(mph,diaInches) = (mph * 5280 / 60) / (2Pi x diaInches / 12) mph x 5280 x 12 mph x 168 = ------------------------ = ------------ 2Pi x diaInches x 60 diaInches overallGearRatio = rpmWheel(evDesiredMph,diaInches) / motorBestRpm torqueWheel = torqueMotor / overallGearRatio x overall Drivetrain eff watt-hours(force_lbs, miles) = Joules(force_lbs,miles)/3600 = force_lbs x miles x 7157/3600 = force_lbs x miles x 1.99 // 1.9885 watts(force_lbs,v_mph) = force_lbs x v_mph x 746watts/HP / 375 = force_lbs x v_mph x 1.99 Weight = Mass x GravitationalConstant // Mass is 'slugs', Wt is lbs GravitationalConstant = 32.2 ft/sec_squared = 9.81 Meters/sec_squaredNumbers, conversion factors, related crap...
1 amp = 6.24 x 10^18th electrons/second 1 BTU = 1060 Joules. 1 gallon of gas = 12500 BTUs = 130 megaJoules, or 36.1 kwh 1 gallon of gas = 33433.9 watt-hours // ref? dif than 36.1 kwh/gal... 1 horsepower = 745.7 watts = 550lb lifted 1 ft in 1 sec = 550 ft-lb/sec = 550 lb, ft/sec ... = 37.5 lb force at 10mph // or 385 lb force at 1 mph etc. 1 Joule = 1 watt-second = 1 Newton-meter, (Energy) = 10E7 ergs = .239 calories = kwh/3600000 = wh/3600 = 0.737 ft-lbs force 1 kw / sq meter = incident solar energy. 1 kwh = 3400 BTUs 1 mi = 1609 meters; 25mpg = 5000 BTUs / mile 1 mph = 1609 meters / hr = 1609m/3600sec=0.447 // .447 ^ 2 is .1997 1 mph = 88 ft/sec 1 Newton = 1kg * 9.81 = 21.58 lbs 1 newton = .2248 lbs of force // => 1 force_lb = 4.448 N, google 1 rho = 2 x .646 wikipedia.org/wiki/Drag_%28Physics%29 1 sq meter = sq_ft * 0.0932 1 watt = 1 Joules/sec = volts * amps = Newtons * meters/sec 1 watt-hour = 3600 Joules walking burns 1/8 kwh per mile. whpm=125 ! 2.0 volt cell reads 1.75 volts when it's at 80% discharge ==================================================================== $0.085 per kwh (quote from tech writer on web. US average. 2006/7?) $0.10 Ed Ring used this value in 2005. might have been a purposefully high approximation. $0.12 / kwh: current cost of electricity in Calif (?) ==================================================================== typ values used for efficiencies: 90% charging efficiency, LA battery 90% motor efficiency in an EV. this proportion gets to traction. 35% ICE efficiency on gasoline. 42% eff for hydrogen system converting electricity to E motor input. vs 90% ====================================================================
Lithium batteries, and some other non-Lead Acid batteries, can be easily destroyed if charged too quickly or too much. Some battery types need all batteries within the pack to be equally charged. All these constraints are serious enough to warrant special charging apparatus known as a BMS.
The blog at evconvert Eve discusses which battery types might need BMS.
1 BTU = 1060 Joules. 1 kwh = 3400 BTUs 1 gallon of gas = 12500 BTUs 25mpg is 5000 BTUs / mile
I've read that you'll get 1.5 x cycles out of a battery if you discharge it to 50% rather than 80%. From the evconvert/eve blog/news.
Gorilla says that a 2.0 volt cell reads 1.75 volts when it's at 80% discharge. A 12v battery is composed of 6 such cells, an 8v battery has 4 cells.
typ values used for efficiencies: 90% charging efficiency. a lead-acid battery gives back 90% of what you put in. 90% motor efficiency in an EV. this proportion gets to traction. 35% ICE efficiency on gasoline. 42% eff for hydrogen system converting electricity to E motor input. vs 90% see PV Photovoltaic, solar cells...
The term EV is applied to very different levels of electrically powered vehicles (each with an acronym I concocted...):
| Lead Acid | 60 w-hrs/kg. x 50%DOD x .57 |
| NiMh | 100 w-hrs/kg |
| Li-ion | 200 w-hrs/kg |
| Li-whatever MM uses | ____ wh/kg |
18.7 kwh LA, 60 AHrs, 312v, 1310 lbs. 3086 lbs total. 26.4 kwh NiMH, 77 AHrs, 343v, 1147 lbs, 2909 lbs total.See copy of EV-1 website
| - | SI | fps g |
|---|---|---|
| force | newtons | pounds force |
| density | kg/cu meter | slugs/cu ft |
| velocity | meters/sec | feet/sec |
| area | square meters | square feet |
A company in Huntington Beach, SoCal. They make small 3 battery "utility vehicles" and they sell plans for the Doran plans-built car.
I encountered an Ebay reference to these people on about Day2 of studying EVs. They were selling the molds to an EV for a large amount of money (100k?). I now (July08) see these same molds mentioned under Miscellaneous items on the Gorilla website.
They mention, and probably sell, a special charging connector (Anderson?)
I ordered the Doran plans from them 7/10/08. $53 thru Ebay & Paypal.
Apparently the main man is 'Rick' (Rick Doran!?).
on door sticker (?) can't exceed this when converting a car.
horsepower: 550lb lifted 1 ft in 1 sec = 550 ft-lb/sec = 550 lb, ft/sec ... "550 lbs 1ft/sec" = 746 watts // 745.7 W HP(force_lbs,v_mph) = force_lbs x v_mph / 375 //brant pg 152 top // "it takes 1 HP to move 37.5 lbs at 10mph" Brant p152 // i think this really says '1 HP pushes a 37.5 force at 10mph' (?)
760 lbs. Theoretically capable of 150 mph. Jamieson DuRette PO Box 426 Bel Air, MD 21014 indycyclebuilder@aol.com $75 for the plans. order 9/3/08 indycyclebuilder@aol.com photos I stole his web site
Joule = 1 watt-second = 1 Newton-meter, (Energy)
= 10E7 ergs = .239 calories = kwh/3600000 = wh/3600
= 0.737 ft-lbs force
// Joule(f,dist)
// uses 1 force_lb = 4.448 N bingo!
Joules(force_lbs, miles) =
= (force_lbs * 4.448) x (miles x 1609 m/mile)
= (N) x ( meters ) // force times distance.
== force_lbs x miles x (1609/4.448=7157)
1 gallon of gasoline contains the energy of 130 megaJoules, or 36.1 kwh
kilo-watt hour walking burns 1/8 kwh per mile. whpm=125 ! cost of electric energy. $0.085 per kwh (quote from tech writer on web. US average. 2006/7?) $0.10 Ed Ring used this value in 2005. might have been a purposefully high approximation. $0.12 / kwh: current cost of electricity in Calif (?) 1 gallon of gasoline contains the energy of 130 megaJoules, or 36.1 kwh.
Least Squared Error. See local info: link
These new(ish) batteries are still very expensive, perhaps 10x the equivalent
cost of Lead-Acid. But equivalent energy Li's weigh 3.3 time less, take less
room etc.
Actually, it would seem from the Transportation Research Board's paper that most tires today are striving for LRR so maybe the term is no longer used.
1 Newton= 1kg * 9.81 = 21.58 lbs google: 1 newton = .2248 lbs of force // => 1 force_lb = 4.448 N
Solar power 1 kw / sq meter incident energy. pointing at sun. having sun unobscured... 20% efficient?
If we use a system of units called fps gravitational this area is measured in sq.ft. If we use SI units this area must be in units of square meters.
A slug is a unit of mass. wt in lbs over 32.2 ft/sec_squared.
see sunnev.com
The stopwatch needed for measuring the decelerating forces on your car should be the type used by athletes. Swimmers, bike racers, runners have stopwatches which display "splits". You start the watch and press a button to show a split; the frozen time shown on the face of the watch is the time you pressed the Split button. The watch however is still running. Pressing the Split button again returns the display to showing the time since the race began.
For the deceleration study, you can start the timer at 60mph, read a split at 55, another split at 50, and so on.
You can borrow such a watch, rather than buying one. But be sure to practice with it before taking measurements in the moving car.
watt = Joules/sec = volts * amps = Newtons * meters/sec
// pg 3 of 4, physics of auto energy consumpt, Koon
watts(force_lbs,v_mph) = force_lbs x v_mph x 746watts/HP / 375
= force_lbs x v_mph x 2
watt-hour = 3600 Joules
gallon of gas=33433.9 watt-hours // ref? this is dif than 36.1 kwh/gal...
// derived fm horsepower(F,Dist). works in ev.c too
watt-hours(force_lbs, miles) = Joules(force_lbs,miles)/3600
= force_lbs x miles x 7157/3600
= force_lbs x miles x 1.98
// derived fm horsepower(F,Dist). works in ev.c too
whpm(force_lbs) = watt-hours(force_lbs, 1 miles) = Joules(force_lbs,miles)/3600
= force_lbs x miles x 7157/3600
= force_lbs x 1.98
1 gallon = 33434 watt-hours 1 gallon/mile = 33434 watt-hours/mile 1 mile/gallon = 1 / (33434 x whpm) = 1 / 33434 miles/wh