By Doug Korthof, Electric Vehicle Activist.
Batteries hold potential ENERGY, the ENERGY (oops, not "power") that will be used to do the work of turning the wheels of the EV. Energy is measured in joules, 3.6 million joules equals one kilo-Watt-hour ("kWh").
Naturally, we lay folks prefer kWh. "...each kWh of potential ENERGY held in the battery has the ability to run the motor...POWER used is determined by he accelerator pedal, it's the energy expended per unit time, which we perceive as the difficulty experienced by the motor in turning the wheels...".
The batteries hold ENERGY in kWh, while that energy is consumed by the POWER of the motor as rated in kilo-Watts ("kW"). One kWh can be sliced up by how many hours at what power level. In an EV, one kWh takes you 3 miles to 6 miles. That same ENERGY will run a 1500 Watt (1.5 kW) hair dryer 45 minutes. One kWh will also run a 2 kW power saw for a half hour. Each kWh on your electric bill will cost you from 5 cents up to 45 cents, depending on billing company and schedule.
A total 28 kWh of ENERGY held in the battery has the POWER to run a 28 kW motor for 1 hours under continuous load, basically, driving at least 80 miles.
This ENERGY is only expended against resistence, of course; when sitting in traffic with your foot on the brake, the electric energy is not used, it's only potential. You have to release the brake and deliver the kWh enegy at a kW power-level to the EV to drive it.
Energy and POWER are terms we use casually, but to a physicist, "power is energy per unit time". Electric energy held in a battery is a clearer concept than mechanical energy. It's like water held in a dam, "storing" a big bunch of potential ENERGY, but measured in "kWh" not foot-pounds.
kWh eliminates all the weirdness of volts, current flow, time, etc., because it's the bottom-line measure of work done. You can't play games with kWh, it's what the utility bills you for, it's the sum of "hours times amps times volts".
We have all this potential energy (kWh) stored in the battery, and we use it at the power-level (kW) we need to drive the EV.
Thus, we measure the raw kWh ENERGY (oops, almost said "power") that's stored in the batteries, and figure out the kW POWER, how fast it can do work by turning the wheels. How fast, in the dam analogy, the water can be released to turn the generator.
Sophisticated engineers talk about batteries in amp-hours ("A-H"), a term designed to baffle the unwashed. Using "A-H" masks the voltage, kWh, size, etc., and serves, IMO, no useful purpose except dissimulation...EXCEPT that it's useful in defusing some oillies. When the oillies say that a pack can't be split, or that a small pack would wear out sooner, that's the time to break out the A-H talk. If the pack is to be split, you just decrease the A-H rating. This involves making smaller plates on each cell in the battery. So to split a "105 A-H battery pack" into a 35 A-H battery pack is done at the manufacturing phase. You just decrease the rating.
Here's how to convert this usually deceptive-speak A-H to familiar kWh: Just multiply by Volts. Since Amps times Volts equals Watts,
WATTS = AMPS * VOLTSit's an easy conversion. Try to get people to use kWh, and ditch the A-H stuff.
WATT-HOURS = AMP-HOURS * VOLTS
Batteries are composed of cells; the A-H are a result of how big the plates in each cell is, so you can have gigantic batteries with huge A-H ratings that are of little use in an EV. You also have to consider, of course, WEIGHT and VOLUME. But let's leave that aside, for now, to look at these examples.
1. 6 volt battery, 167 A-H is (6*167) 1000 Watt-hours, or 1 kWh. 2. 12 volt battery, 83 A-H is 1000 Watt-hours, or 1 kWh. 3. 120 volt battery pack, 39 A-H is 5 kWh. 4. 288 volt battery pack, 105 A-H is 30 kWh. 5. 48 volt battery pack, 255 A-H is 12 kWh.
1. Typical 6v Golf-cart battery, weigh about 60 lbs. and used in conversions like the S-10.
2. Typical 12v Golf-cart battery, weighs about the same. Or, just series-mount two 6v for double the kWh and double the weight.
3. Typical Optima Yellow-Top (now owned by Johnson Controls, GM supplier) pack of 10 12v batteries in series. They are rated 39 A- H, or .5 kWh each 12v module. 5 kWh for a pack of 10. In a "parallel-series" configuration you can double them up to get 78 A- H, 20 batteries in two parallel strings of 10 in series to run a low- performance motor without regenerative braking. This can achieve 10 kWh.
4. This is the Nickel Metal Hydride pack in the Toyota RAV4-EV, using "gen-III" technology that the Chevron-funded lawsuit penalized them for using when Chevron's JV cobasys won $30 million and a settlement from PEVE, which had been improving NiMh since it went into production in 1997. PEVE (Toyota and Panasonic) might have prevailed, at law, but may have stood no chance fighting the oillies in the real world. So they surrendered.
5. This is the 600 lb. battery backup for a typical solar PV system, either 4 12v gigantic golf cart batteries in series, or 16 6v golf cart batteries in parallel-series.
Now it's easy to see that the EV-95 NiMH is unique when compared to lead-acid. When you look at the weight, the comparison is even more enticing: the 24 EV-95 batteries (each composed of 10 1.2v cells) in the (nominally 288v) RAV4-EV weigh about 780 lbs., or about 26 lbs. per kWh.
The unique thing about NiMH is that it lasts so long; the three things that an EV needs are:
1. Adequate power to accelerate without help from an IC engine;
2. Deep cycling, so that it can use at least 25 kWh per cycle (about 100 miles per cycle);
3. Long cycle life, at least 1000, preferrably 2000, for a life of 100k to 200k miles on a pack.
Lithium is even more enticing from a weight, volume and power standpoint, but so far, the long cycle life has not been demonstrated. Perhaps it will.
WHY CHEVRON OIL IS A TRAITOR TO AMERICA
Using our ability to convert, let's assume that Chevron-cobasys ordered Toyota not to use NiMH on any plug-in cars, and not to use any NiMH battery greater than 10 A-H.
Now the original 288v NiMH battery pack in the Prius, if 10 A-H, contained no more than 10*288 or 2.88 kWh. But we now know that these batteries are limited to only cycle part of that range, or no more than 1 kWh. So effectively, not more than 3 miles of driving without using gasoline.
The need for plug-in cars transcends money or commercial interest. Lives are being lost fighting for oil, while treasure is expended in handouts to foreign dictators to support our oillies efforts.
In WWII, companies that held back vital resources or techniques, such as the Norton, Radar, armor-plate, jet technology, atomic power, etc., would be considered "fifth columnists" for the enemy. Wastrels and gold-bricks were exposed and punished by Harry S Truman, who was the most visible "dollar a year" man.
Now, Chevron Oil is making an economic argument, confused and incoherent, for why it is hogging control of the NiMH batteries, while GM is pretending that NiMH does not exist, and claims the success of the plug-in idea depends on Lithium batteries. Perhaps it does; but the fact that jet engines were not yet ready didn't stop Grumman from making a great propellor fighter.
If these two companies, GM and Chevron, were not traitors, they would release or develop the NiMH plug-in car, while waiting for Lithium.
We know, after all, that NiMH works, and is economically feasible, no more than 6.5 cents per mile in life-cycle battery cost.
Instead, these two TRAITORS, Chevron and GM, put their perceived economic interest, in selling more petroleum at higher prices, above the national interest, which is to reduce dependence on overseas oil imports and reduce vulnerable oil supply lines.
In WWII, kids went out and collected tin foil and cans, and people grew victory gardens; gas was rationed, and new tires were mostly for the military due to scarce rubber supply lines and the need to conserve petroleum for the war effort.
Now, Chevron and GM are selfishly squatting on a technology that is recognized as important to our military survival, and could be used to substitute for a signifcant part of our gasoline usage...but to the perceived detriment of Chevon's oil sales and GM's SUV sales, they think.
They are suckling on the milk of the freedom granted by Miss Liberty's bountiful embrace, using their freedom to destroy our future, that's what makes them TRAITORS.
Posted to Yahoo Groups Electric Cars for Sale March 24, 2007.
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