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Electric bikes

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  • 18-11-2008 11:55pm
    #1
    HBAMS
    Registered Users Posts: 287 ✭✭


    What Electric bikes would you recommened???


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    #2
    CheGuedara
    Registered Users Posts: 2,030 ✭✭✭CheGuedara


    I understand that the Giant ones are pretty good. Called the twist or twister or something.....


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    #3
    SharkWound
    Registered Users Posts: 22 ✭SharkWound


    there is an electric bike for sale on gumtree


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    #4
    Freewheeling Ed
    Closed Accounts Posts: 81 ✭✭Freewheeling Ed


    I have never used one, but I remember talking to a woman who had one, because she siad it was easier. But the impression I got from her, that when the battery ran out (was was regular) you end up pushing a really heavy lump of bike around.
    She put me off electrical bikes for ever.
    Have I the wrong end of the battery chager ???


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    #5
    Lumen
    Registered Users Posts: 31,049 ✭✭✭✭Lumen


    Freewheeling Ed wrote: »
    But the impression I got from her, that when the battery ran out (was was regular) you end up pushing a really heavy lump of bike around.

    Cars are a bit like that too. :P

    More seriously, I think electric bikes are a nice idea.

    Consider a bike with 100 18650 LiIon batteries secreted about it's frame. Each battery gives about 8WH for about 50g and $4.50, so that's 800WH of energy for $450 and 5kg of battery weight. Add another 5kg for powertrain, and you have a 20kg bike. With an 80kg rider, that's 100kg to shift.

    I'd want my electric bike to do maybe 1000m of climbing on a spin. I don't mind handling the air resistance, just not the climbing - I'd like to (say) climb up to Sally Gap at 30kph.

    Simple E=mgh gives 1 million joules of energy required at 100% efficiency. That's only 278WH.

    So my theoretical 20kg electric bike could handle 2800m of climbing at normal "flat" road speeds, before drivetrain losses.

    If such a bike exists, I'd buy one. Somehow, I fear that reality doesn't yet meet the theory.


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    #6
    72hundred
    Registered Users Posts: 1,333 ✭✭✭72hundred


    Lumen wrote: »
    I'd like to (say) climb up to Sally Gap at 30kph.

    Does that not just defeat the purpose of cycling :p? :rolleyes:


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    #7
    Ghost Rider
    Registered Users Posts: 1,883 ✭✭✭Ghost Rider


    Not if you live in the Sally Gap...
    72hundred wrote: »
    Does that not just defeat the purpose of cycling :p? :rolleyes:


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