"doctor who" <[EMAIL PROTECTED]> wrote: > > My point is that when you wrap a EV around a tree or have a serious accident > there is the potential for a Hazmat situation (drip or no drip it's still > acid and hydrogen),
You only really have to worry about hydrogen buildup while charging, and then only if your ventilation is inadequate. Most modern batteries have a catalyst grid in their tops that recombines the majority of the oxygen and hydrogen before it escapes the battery case. > electrocution or electrical fire. Those are the real worries with EV's. > Whereas compressed air > is just that. Sweep up the pieces and go. Even if the pieces are 3 blocks away. > I'm still looking for some life span studies on batteries as compared to > compressed air. The folks over at Home Power Magazine can help you there. In home power stations old fashioned wet cell lead acid batteries if properly maintained last 10 years, and many last 20. In one of their experimental installations they're testing some wet cell nicads, and I remember reading that they had one cell which was 50 (fifty!) years old and still producing its rated capacity. > I cannot believe that the manufacture, maintenance and > disposal cost for batteries is lower than that of compressed air systems. Disposal cost is a nonissue. There are recyclers out there that will pay you for your old batteries. They won't pay you _much_, but the lead and plastic in the batteries are valuable. > If > so I better go replace my pnuematic jackhammer with one of those battery > operated rigs. Nah. When it comes to impact force pneumatics beat everything else except explosives. That's why jackhammers and impact drills were some of the first uses for industrial compressed air systems. > So what exactly is the volt/amp conversion to psi? My ratchet wrench at > 60psi is far more efficient than my 3/8" cordless 18volt drill. I doubt that, but don't have any figures to argue with. But be careful about demanding too much torque from one of those little ratchet wrenches. It's just a little turbine and little gears. If you demand too much torque out of them you'll wear out the gears. In the shop environment, where the air tools really shine is in safety. Since they don't throw any sparks they're a lot less likely to start fires, particularly when you have flamable fumes around. Also, you don't have to have extension cords around, just hoses, which are less likely to break. As an added bonus, hoses don't suffer from the same kind of power losses with length that extension cords do. An important consideration if your worksite is a hundred feet away from your nearest source of power. > So I am > assuming since it takes far less energy [electric energy utilized by the > compressor] from the pnuematic ratchet wrench to do the same amount of > torqued turning. This is based on similar RPM's/torque ranges. The same amount of torqued turning will take the same amount of energy at the tool tip. Any more or less energy will be taken up in internal losses, not just in the tool, but in whatever powers it. > It takes > approximatly an hours worth of energy to recharge the battery for an hours > usage. At a couple of hundred milliamps on the AC side. > While it is low voltage DC, alot of energy is wasted off as heat. Not as much as you might think. Cooling off hot compressed air wastes a lot more. > The > compressor takes five minutes of AC voltage to charge the tank for the same > amount of usage. At about 20~30 amps. An hour at an amp, or 15 minutes for 20 amps. You do the math. > Granted its low pressure compressor but even using a > 4500psi tank regulated down I can go all day on one tank. 4500 psi is not low pressure. > My battery tools > do not compare. Then either get more batteries, or bigger batteries. > By weight my air tools are much lighter than my equivilantly powered > electric tools (battery weight included). Are you including the weight of the tank in the weight of your air tools? > So if I apply the eqivilant > weights to a vehicle one could figure that a compressed air vehicle would > weigh signifigantly less than a high torque electric motor, battery bay and > the 4 miles of heavy gauge copper wire. Electric vehicles need the extra > power of batteries to propulse the added weight. Where do you get that 4 mile figure? Granted my direct experience with EV's is limited to golf carts, but I never saw anything like that much wire in them. I can't imagine that larger EV's take much more heavy guage wire than the golf carts, given its purpose. Granted we are talking an order of magnitude difference in the power required. Even reading the parts lists of some of the electric Rabbit conversions I didn't see anywhere near that length of wire. > On another note what is to stop someone from adding a generator/alternator > to one of the drag wheels to power a high efficiency compressor? As long as > you dont exceed the maximum recovery rate of the compressor, your station > refills could be limited to the occasional pressure top off for those heavy > loads. The words "perpetual motion" come to mind. > EV's compared to dino burners are signifigant improvement over belching out > clouds of thick black carbon. However they are no where near as clean as a > bicycle. (Since we are comparing apples and oranges). That depends on the rider's flatulence. ;-) > While EV's are an > improvement over the combustion engine they just are not practical for > anything over a trip to the grocery store or errands. They were never intended to be. Since something like 98% of car trips are of 50 miles or less that is the intended mission profile of electric vehicles. > You will never see a > practical EV long haul tractor trailer. No, but Oshkosh Diesel is already producing a hybrid heavy truck that gets something like 30% better fuel mileage than its conventional counterpart. All because the diesel-electric drive system has less loss to friction than does the conventional drive system. > And I have yet to see any EV that > will drive straight thru from Virginia to Florida at highway speeds. And you likely never will. It isn't in their mission profile. But many of the EV's that I've seen have provisions for an auxiliary generator to be towed behind them that would turn them into hybrids for the duration of long trips. In practice, if they were produced in enough numbers, an EV owner could use his car normally as an EV for everyday use, and then rent an auxiliary generator for long trips. But then I suppose a compressed air vehicle could do the same thing with an auxiliary compressor. > I like > to get there without 8 hour layovers for the car to charge. I agree, wholeheartedly. > Compressed air technology has the advantage of substituting liquid gas for > compresssed gases for the purpose of increasing the ranges. What liquid gas did you have in mind? Most of the liquid gasses I know of either have to be stored under really high pressure, are flamable like propane, are noxious like ammonia, are really serious greenhouse gasses like HFC's, or have to be kept cryogenically cold. > EV's stay > relativly constant with the amount of charge they will contain and last time > I checked they still take several hours to gain a full range charge. True. > Another > advantage is the wasted energy from gas expansion is used to the cool the > vehilce. Not an advantage in winter. And in any event, that's heat uptake that replaces heat that was lost when the gas was compressed, and would be better spent running the engine. > Do they make EV's with AC? Yes, but at the cost of range. > Sure it takes energy to power the compressors. I'd love to see a high > compression plant powered by alternative energies. If that where to be the > case than IMHO the EV car theory would be put aside as the antiquated > technology it is. EV technology is no more antiquated than is compressed air technology. > While most EV'ers are responsible eco-minded folks as hybrids become common > place and EV's see higher implementation you will find more battery bays > sitting in trash piles on backroads, along with tires and other "valuable" > recyclable trash. Ultimatly the cost of getting rid of used batteries [will > rest on the consumer], and will send more to the dumps/landfills/trashpiles. I doubt that. If the demand for batteries increases then the value of the recyclable materials in them will go up. As it is right now a recycler will pay US$3-5 for an average car battery. The really big ones more than that. Multiply that by the size of an EV's battery bank and it's a couple of hundred. People might waste the price of a hamburger, but they aren't going to waste a couple of hundred dollars, particularly if it offsets the cost of a new battery bank. > It's human nature to be wastefull. Sad but true. > In my mind the most eco-friendly vehicle is one that does not create > hazardous waste in unfavourable conditions. Agreed. > (being your typical junkyard or > trashpile at the end of the vehicles usefull life, how many ppl are going to > pay to pull the batteries out before they junk these cars?) (They won't, they'll get paid to do it. Selling recyclable batteries is part of what junkyards do. In fact junkyards usually pay people for their junk cars, at which point they do everything they possibly can to make money from them. That's how those folks stay in business.) > There are ppl in > this country who pay for oil changes, you can forget about these folks > pulling a few hundred pounds of corroded batteries out so they can take it > to the retailer/recycler. They won't have to. The recycler will pay them. Or at least pick them up at no charge. In any event, the folks who pay for oil changes would more than likely be paying a shop to replace their battery bank, at which point disposal becomes the shop's problem. You can bet good green and black american money that the shop owner is going to do whatever makes him the most money, and that will probably be selling the removed spent batteries to a recycler. In fact, most of the shop owners I know would sell the batteries to a recycler and then refund the value of them to the customer. Customers like that sort of thing, and repeat business is more important that a quick buck. In any event, the next time you replace a car battery, and don't have an old battery to trade for it, see if you don't pay a core charge. Last time I bought a car battery without a trade-in I paid an US$8 core charge. Battery manufacturers like to get the old ones back so they have less expensive materials to make new ones with. > For me EV's just havent met my low impact standards yet. Regardless of > wether an air car cleans the air or not, if it has a nuetral enviromental > impact. It has one leg up on EV vehicles. _If_ it has a neutral environmental impact, which has not yet been established on either side of the argument. > In any case I havent seen solid > figures for the air car yet so I'm going to end my theoretical jousting on > that note. Agreed. End of joust. Good blows, well struck, sir. Now if someone will hurry up and invent a TARDIS... ;-> Alan Petrillo -- Aviation is more than a hobby. It is more than a job. It is more than a career. Aviation is a way of life. A second language for the world: www.esperanto.org Processor cycles are a terrible thing to waste. www.distributed.net ------------------------ Yahoo! Groups Sponsor ---------------------~--> Small business owners... Tell us what you think! http://promo2.yahoo.com/sbin/Yahoo!_BusinessNewsletter/survey.cgi http://us.click.yahoo.com/vO1FAB/txzCAA/ySSFAA/FGYolB/TM ---------------------------------------------------------------------~-> Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Please do NOT send "unsubscribe" messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
