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Can all-electric vehicles take charge?

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graduatesoftware
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re: Can all-electric vehicles take charge?
graduatesoftware   11/24/2009 2:49:18 AM
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Absolutely. Charging rate is most definitely a concern for all-electric vehicles, but it is not an insurmountable problem. Using a very rough (and conservative) figure of 1 kWh / mi, the amount of charge that must be restored after a 50 mile round-trip commute is 50 kWh. Dumping 5 kW (200V @ 25A) over 10 hours would recharge the batteries (for a cost of around $5). But let's look at the problem another way. We can certainly discharge the batteries at 50 mi/hr (a number of electric cars already demonstrate this). So we are consuming the 5 kWh in one hour's time without blowing anything up or melting anything down. Therefore (assuming the charge/discharge thermodynamics are the same), we ought to be able to put the charge back into the batteries over the same period of time without risking overheating the batteries, wires, controllers, etc. To do so, however, will likely require some changes to the electric service in your home. Instead of 200V x 25A x 10h, you would need 200V x 250A x 1h. Another thing to consider in this discussion are the battery technologies that have replaceable charge carriers (such as Zinc slurry in the Zinc-Air battery being developed by Revolt).

nexogen
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re: Can all-electric vehicles take charge?
nexogen   11/19/2009 7:45:38 AM
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Look, the problem isn't battery technology, the problem is, at the essence, the money based economy. We can have free energy and free food with the current technology, we can have them in abundance. With this, money would be obsolete. Automation can replace human labor. The only thing stopping this from happening is the money based system. This system is also promoting planned obsolecence and deliberate product inefficiency due to the consumption cycle needed to maintain it. It is also fooling us into beliving that we need oil and that batteries are inefficient. The system needs inefficiency and scarcity, it feeds on it. You need to give this a good solid thought and realize the implications.

AlexKovnat
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re: Can all-electric vehicles take charge?
AlexKovnat   11/16/2009 1:39:18 PM
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Whether tomorrow's road going citizenry goes about their daily business in a hybrid-electric or a pure electric car, I would say the most urgent need right now is for us to work out the technical problems with lithium ion batteries. Where I work, there's a guy who's administering a development program for lithium-air batteries, and there has also been talk of lithium-sulfur batteries. Let us hope at least one of these concepts succeeds. There is another research need I'd like to point out: Fuel cells. Fuel cells are all right if you don't mind their fussy fuel appetites, which at this moment can be met only by hydrogen. I'd rather not have to deal with H2. There is the possibility of using methanol in fuel cells directly, without a technically difficult reforming step. But even if you want to use a reformer, methanol is easier to reform into hydrogen than gasoline. Researchers should look into the matter of whether you need chemical-grade methanol for a direct methanol fuel cell to work, as opposed to CH3OH with higher alcohols or other impurities that might be present with non-chemical grade methanol. Will non-chemical grade CH3OH be substantially more difficult to reform, or use directly in a fuel cell? If this issue can be worked out, and if researchers can work out the problem of producing methanol via direct oxidation of methane (i.e. 2CH4 + O2 --> 2CH3OH, as opposed to CO + 2H2 --> CH3OH synthesis), I think fuel cell-electric vehicles would be a viable option. And all the more so, if you use first-rate lithium ion batteries for load leveling.

BicycleBill
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re: Can all-electric vehicles take charge?
BicycleBill   11/13/2009 3:44:55 PM
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Have to disagree, you also have to look at it in terms of work being done, and the prime mover. Othewise, why use a larger hp motor when a smaller one will do?

ump
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re: Can all-electric vehicles take charge?
ump   11/12/2009 9:19:20 PM
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It is just wrong headed to use the motor's size to gage the needed battery's capacity or recharge energy. It's the energy required to overcome resistance to moving the vehicle (wind, tires etc.) vs. time that determines the bulk of battery recharge energy (in a perfect world). It's the acceleration/deceleration rates and vehicle weight that will relate to the motor's size. Further, much of the energy used to accelerate can be recoved by deceleration. So, even for a back of the envelope reality check, the battery recharge time does not relate to the HP size of the drive motor.

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