On Thu, 11 Jun 2015 22:15:07 +0000 (UTC), Cursitor Doom wrote:

Are the bikes *really* pushing out 160bhp *all* that time?

You've never seen a TT race, clearly. ;-)

No but I know enough about motorsport to know that the GO and STOP
controls are digital, just two states full on or off.

Only on the open to the public roads around here, which reminds me I
must get the dashcam out of the car and see what it caught of a bike
hurtling around a RH bend (for them) at not much more than 30 deg up
from the horizontal. If I'd been a second or so earlier his head
would have been pretty much inline with my headlight...

How many charge cycles were there?

Not known - yet. However, we can now deduce it from the 7 quid per
charge figure by subtracting the units used this time from a normal bill
from the same period last year. AOTBE of course.

Does your pal use any electricity for space heating and is the
billing period monthly or quarterly. Space heating can be very
seasonal, if this time last year just happened to be cold it could
mask the energy given to the bikes.

My workings would be worst case, others more realistic but if you
have the bike spec and get the maximum battery capacity. You'd get
simpler maths and a better guide to how much energy is likely to have
been used.

battery_capacity kWHr * number_of_charges = nominal_energy

Effciency guesstimate at 80% in (but probably better) 80% out
(probably worse due to the high discharge rates). Two lots of 80%
gives an overall effciency of 64%, call it 60%.

total_energy_input = (nominal_energy / 60) * 100

total_cost = energy_input * p/kWhr

--
Cheers
Dave.