• need fast charging time high density battery packs are a boosting field. i think it is in the right direction of future transportations. the main concern is about the time taken to charge the batt-back. last week LOTUS GT introduced it's 700 horse-power Electric Vehicle which charges up in just 10 minutes for a 200 mile run! this will be challenge for all high density automobile battery designers

  zakir.ak 08/05/2008 Posts:6 Avg Rating:

  • Re: need fast charging time When they quote a mileage run, say 200 miles, does that mean without a radio, air conditioner or headlights on? If so, what reasonable reduction can you assume with any or all of these items in play?

    dasein 08/05/2008 Posts:1 Avg Rating:

  • Re: need fast charging time A short charging time means high current. One way to achieve this is by discharging a charged EESU into an empty one.  But notice that the resultant two EESUs will come to equilibrium holding 1/2 of the original charge in each unit.  Hence to have the uncharged  EESU come to equilibrium at 350 volts it is necessary for the precharged EESU to be charged at a higher voltage.  If we assume there is no loss in energy in the charging process (a false assumption) then we need to equate energy before and after the equilibrium state.  If V is the larger voltage of the 'charger' and v is the equalibrium voltage of the two units and noting that the energy in a capacitor with capacitance C is 1/2 C v^2 then we must have 1/2 CV^2 = 1/2 Cv^2 + 1/2 Cv^2 or V^2 = 2v^2 or V ~ 1.4v For v=350 volts we find the 'chargers' voltage must be equal to or greater than V = 490 volts As long as that voltage is much smaller than the breakdown voltage of the unit all is well. I just thought one should realize that the 'home charging unit' must operate at 490 volts in order for the car's unit to operate at 350 volts.

    DGDanforth 08/05/2008 Posts:1 Avg Rating:

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