On 12/06/2015 06:55, harry wrote:
On Thursday, June 11, 2015 at 10:11:59 PM UTC+1, Cursitor Doom wrote:
Hi all,

A pal of mine is hosting one of the TT Zero teams for this year's
competition. This is a race for the newish category of zero-emission
electric bikes. They're developing very rapidly currently and are at
present capable of putting out 160bhp for 37.75 miles (one lap) at least
(on a good day anyway). Some online calculator I've tried states this is
equal to about 120kW but that seems like an awful lot to me and surely
cannot be right. I was just wondering what sort of electric bill he can
expect (after they've gone home, obviously). They made several overnight
charge-ups during testing and he said his breakers were repeatedly
tripping out. Anyone care to do the maths? You'll have to allow for
efficiency as well, of course, since the 160bhp is the power OUT. I'll
pass on the result when I see him again tomorrow (assuming it's not too
horrible, that is, as he has a heart condition).

cheers, cd.

Ball park figures.
I have an electric car.

Almost...

The battery size is 16Kwh (weighs almost a ton)and is far bigger than any bike.

Shows how crap in comparison the technology is in your car must be
then... the whole bike is less than 300kg and has a 14kWh[1] battery.

[1] note the proper use of units - it seems some round here don't
understand energy or power!

This will take me about 80 miles.
So a bike is likely to have around a quarter of this (let's say).

Yes that's a realistic assumption for a bike designed to lap a race
course that is nearly 40 miles long - NOT!

So a bike is likely to need say 4 Kwh per charge.
So each charge up would cost around £0.75

Battery chargers come in various sizes, if they had fast chargers than maybe his breakers would trip.

My car has a slow charger (2.2Kw) and would take 8 hours from complete depletion.


--
Cheers,

John.

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