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.

Cursitor Doom wrote:

Anyone care to do the maths?

Assume 20 minute laptime to achieve average speed of 118mph as reported
elsewhere (spherical cows and all that) your 120kW is right assuming the
horsepower is right, so about 40 kWh per lap, allow 75% efficiency from
meter to tyre maybe, manx rates seem to be 16.75p/unit plus VAT
(presumably 5% same as here) so about £7 per fill-up ...

On Thursday, 11 June 2015 22:11:59 UTC+1, Cursitor Doom wrote:
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?

Depends on which breaker was tripping.

Assuming lots of things like a steady sustained load and a breaker tripping exactly on rated current,

32 Amp socket ring circuit = 7.680 kW load at 240 volt.

7.680 kW for 8 hours overnight charge = 61 kWh

61 kWh @ say 12p / kWh (depends on electricity tariff) = £7.30

Unless I've misplaced a decimal point somewhere.

Owain

On Thu, 11 Jun 2015 22:39:10 +0100, Andy Burns wrote:

Cursitor Doom wrote:

Anyone care to do the maths?

Assume 20 minute laptime to achieve average speed of 118mph as reported
elsewhere (spherical cows and all that) your 120kW is right assuming the
horsepower is right, so about 40 kWh per lap, allow 75% efficiency from
meter to tyre maybe, manx rates seem to be 16.75p/unit plus VAT
(presumably 5% same as here) so about £7 per fill-up ...

Thanks for that, Andy. Not that it makes any difference to speak of but
Manx juice costs 16.01p /unit and VAT is the same. I'll inform him
accordingly.

Tim Streater wrote:

Cursitor Doom wrote:

capable of putting out 160bhp for 37.75 miles

160HP is 120kW, near enough (the distance is irrelevant).

Irrelevant to the power, but not the energy ...

On Thu, 11 Jun 2015 21:10:41 +0000 (UTC), Cursitor Doom wrote:

A pal of mine is hosting one of the TT Zero teams for this year's
competition.

Surely there is some compensation payment involved in the agreement
for them being hosted by your pal?

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 ...

Electricty is billed by the energy consumed (kWHr) not the power (kW
or bhp).

So how long does that 37.75 mile lap take 'em to do? google 23'22"

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

Lets find a fag packet and make some gross assumptions.

160 bhp is 160 * 0.745 = 119.2 kW

Use energy at that power level for 23'22" (0.39 hrs) it would be
46.48 kWhr. 50% effcient? Call it 100 kWhr of energy @ 15p/unit = 15
squid per charge cycle.

How many charge cycles were there?

--
Cheers
Dave.

On 11/06/2015 22:10, 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.

1 hp = ~750W, so that sounds about right.

What makes you think its unrealistic? With the right battery technology
you can suck amps out of them at a ferocious rate.

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.

The power out tells you nothing much of any use directly. Ideally we
need to know the energy density of the battery pack for an accurate answer.

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).

ok a wild stab in the dark: (figures could be out by a significant margin!(

Well let's say the bike is competitive, and it can lap in 20 mins. If it
were running at full power for say 50% of the lap (don't know if these
things have any energy capture from regen breaking?) That would give a
total energy output of say 120 * 0.5 * 20/60 = ~20kWh

That would suggest a battery capacity of something in the order of 30kWh

(by comparison the latest Nissan Leaf boasts a 24kWh battery) - so that
may be a bit of an over estimate for something that fits into a bike
(unless it has a side car for the battery!).

Still 24kWh would equate to anything from five to ten quid a charge
depending on how efficient the charging process is.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Thu, 11 Jun 2015 22:44:19 +0100, Andy Burns wrote:

Tim Streater wrote:

Cursitor Doom wrote:

capable of putting out 160bhp for 37.75 miles

160HP is 120kW, near enough (the distance is irrelevant).

Irrelevant to the power, but not the energy ...

Sorry, Andy. I did mean to include the 20 minutes bit but fortunately you
had the nous to fill that blank in. Unlike some people.

On Thu, 11 Jun 2015 22:54:14 +0100, Dave Liquorice wrote:

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

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

[...]
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.

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.
The battery size is 16Kwh (weighs almost a ton)and is far bigger than any bike.
This will take me about 80 miles.
So a bike is likely to have around a quarter of this (let's say).
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.

On Thursday, June 11, 2015 at 10:56:46 PM UTC+1, John Rumm wrote:
On 11/06/2015 22:10, 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.

1 hp = ~750W, so that sounds about right.

What makes you think its unrealistic? With the right battery technology
you can suck amps out of them at a ferocious rate.

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.

The power out tells you nothing much of any use directly. Ideally we
need to know the energy density of the battery pack for an accurate answer.

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).

ok a wild stab in the dark: (figures could be out by a significant margin!(

Well let's say the bike is competitive, and it can lap in 20 mins. If it
were running at full power for say 50% of the lap (don't know if these
things have any energy capture from regen breaking?) That would give a
total energy output of say 120 * 0.5 * 20/60 = ~20kWh

That would suggest a battery capacity of something in the order of 30kWh

(by comparison the latest Nissan Leaf boasts a 24kWh battery) - so that
may be a bit of an over estimate for something that fits into a bike
(unless it has a side car for the battery!).

Still 24kWh would equate to anything from five to ten quid a charge
depending on how efficient the charging process is.

Drivel.
All is down to battery size.
Which we can only guess.
Tripping is down to how big/fast the battery charger is.
Again we can only guess.
Nothing else is relevant.

On Thursday, June 11, 2015 at 10:44:21 PM UTC+1, Andy Burns wrote:
Tim Streater wrote:

Cursitor Doom wrote:

capable of putting out 160bhp for 37.75 miles

160HP is 120kW, near enough (the distance is irrelevant).

Irrelevant to the power, but not the energy ...

A lot of people here don't know the difference between power and energy.
Bad education.

harry wrote:

I have an electric car.
The battery size is 16Kwh (weighs almost a ton)and is far bigger than any bike.

The TTzero bikes are limited to 300kg

This will take me about 80 miles.

I presume the bike is designed to run out of juice as soon after it
crosses the line as is possible.

http://www.autoblog.com/2015/04/03/mugen-reveals-shinden-yon-electric-superbike

So a bike is likely to have around a quarter of this (let's say).
So a bike is likely to need say 4 Kwh per charge.
So each charge up would cost around £0.75

You seem to be thinking about a toy scooter, not something that did this
last year ...

https://youtu.be/vlxZs2-gICc

On 12/06/2015 06:55, harry wrote:

Ball park figures.
I have an electric car.
The battery size is 16Kwh (weighs almost a ton)and is far bigger than any bike.

Are you sure its not a milk float?
The whole bike with a 14kWHr battery is a quarter of a ton.

This will take me about 80 miles.

The bike does 120 miles.

dennis@home wrote:

This will take me about 80 miles.

The bike does 120 miles.

It's a single 37¾ mile lap, the superbikes refuel every other lap, how
many years before the electric bikes can do two 130mph laps on a charge?

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.

On Thu, 11 Jun 2015 22:55:48 -0700, harry wrote:

I have an electric car.

Do you, Harry? I don't think you've mentioned it before.

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

The battery in Harry's i-MIEV is actually 200kg, and the car is a ton and
a half.

Anyway, how did he escape from my bozobin?

Dave Liquorice wrote:

My workings would be worst case, others more realistic

With one predictable exception, maybe they could have a TT triple-A
class for harry?

wrote:

32 Amp socket ring circuit = 7.680 kW

You'd hope they'd be a bit more prepared (e.g. temporary 32A commando
plug on a cooker or shower circuit) rather than two 13A plugs with
welders fuses on a Y cable ;-)

7.680 kW for 8 hours overnight charge = 61 kWh
61 kWh @ say 12p / kWh (depends on electricity tariff) = £7.30

Nice that calculating from a different direction comes to a similar
estimate.

On 11/06/15 22:10, 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

Why. Its correct. Its about what a small windmill puts out in a force 9
gale.


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?

60A trip at 240v is around 144kW... 10 hours at that rate would be 1440
units or at 10p a unit 144 quid give or take.


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.



--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

On 2015-06-12, harry wrote:

On Thursday, June 11, 2015 at 10:44:21 PM UTC+1, Andy Burns wrote:
Tim Streater wrote:

Cursitor Doom wrote:

capable of putting out 160bhp for 37.75 miles

160HP is 120kW, near enough (the distance is irrelevant).

Irrelevant to the power, but not the energy ...

A lot of people here don't know the difference between power and energy.
Bad education.

It's just a matter of time...

On Friday, 12 June 2015 09:37:43 UTC+1, Andy Burns wrote:
32 Amp socket ring circuit = 7.680 kW
You'd hope they'd be a bit more prepared (e.g. temporary 32A commando
plug on a cooker or shower circuit) rather than two 13A plugs with
welders fuses on a Y cable ;-)

They could have had multiple bikes (or chargers, if the battery pack splits into sections for charging) on multiple plugs.

Owain

In article ,
harry wrote:
I have an electric car. The battery size is 16Kwh (weighs almost a
ton)and is far bigger than any bike. This will take me about 80 miles.
So a bike is likely to have around a quarter of this (let's say). So a
bike is likely to need say 4 Kwh per charge.

There is a big difference in energy needed between pootling around at 20
mph and racing.

Unless you thing an F1 petrol car gives better MPG than a Mini, because
it's lighter.

--
*You can't trust atoms - they make up everything.
Dave Plowman London SW
To e-mail, change noise into sound.

On 12/06/2015 06:59, harry wrote:
On Thursday, June 11, 2015 at 10:56:46 PM UTC+1, John Rumm wrote:
On 11/06/2015 22:10, 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.

1 hp = ~750W, so that sounds about right.

What makes you think its unrealistic? With the right battery technology
you can suck amps out of them at a ferocious rate.

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.

The power out tells you nothing much of any use directly. Ideally we
need to know the energy density of the battery pack for an accurate answer.

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).

ok a wild stab in the dark: (figures could be out by a significant margin!(

Well let's say the bike is competitive, and it can lap in 20 mins. If it
were running at full power for say 50% of the lap (don't know if these
things have any energy capture from regen breaking?) That would give a
total energy output of say 120 * 0.5 * 20/60 = ~20kWh

That would suggest a battery capacity of something in the order of 30kWh

(by comparison the latest Nissan Leaf boasts a 24kWh battery) - so that
may be a bit of an over estimate for something that fits into a bike
(unless it has a side car for the battery!).

Still 24kWh would equate to anything from five to ten quid a charge
depending on how efficient the charging process is.

Drivel.

Is this a comprehension problem of yours, or just your normal lack of
technical nous?

All is down to battery size.

Which part of "Ideally we need to know the energy density of the battery
pack for an accurate answer" did you not understand?

Which we can only guess.

Which I and others did - as it turns out, I guessed at about double the
actual value, but since it turns out the continuous power rating of the
motor is only 70kW, rather than 120kW, it was actually not a bad guess.

Tripping is down to how big/fast the battery charger is.

I made no mention of "tripping"... perhaps those pills you have been
popping are having that effect on you?

Again we can only guess.

Which part of "ok a wild stab in the dark: (figures could be out by a
significant margin!)" did you not understand?

Nothing else is relevant.

This is why you have such a poor grasp of engineering harry.

You will note that a number of people here managed to take what limited
data were available, and arrive at an estimated answer to a question
from first principles and some educated guesswork. The answers were all
relatively close, as well. Meanwhile you sit there scratching your arse,
spluttering "drivel" as if that is a relevant contribution to a discussion!

Now we have more information (from Jonno's link) we actually know the
battery capacity is 14kWh and has a 5 hour standard charge time, or 1.5
hours with a fast charger. We also know the battery technology is LiPo
which has a very high charge efficiency - so the main cause of energy
loss in charging will be heat losses from the charger.

Its probably safe to assume the "standard" charger will be designed to
run from a socket and will limit itself to 3kW or 12.5A. The five hour
charge would thus consume 15kWh.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 12/06/2015 06:59, harry wrote:

Drivel.

Cheers
--
Syd

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.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Friday, June 12, 2015 at 7:13:28 AM UTC+1, Andy Burns wrote:
harry wrote:

I have an electric car.
The battery size is 16Kwh (weighs almost a ton)and is far bigger than any bike.

The TTzero bikes are limited to 300kg

This will take me about 80 miles.

I presume the bike is designed to run out of juice as soon after it
crosses the line as is possible.

http://www.autoblog.com/2015/04/03/mugen-reveals-shinden-yon-electric-superbike

So a bike is likely to have around a quarter of this (let's say).
So a bike is likely to need say 4 Kwh per charge.
So each charge up would cost around £0.75

You seem to be thinking about a toy scooter, not something that did this
last year ...

https://youtu.be/vlxZs2-gICc

Well there you go.
The bikes battery is 30% the size of mine. (16Kwh)
Ergo the energy capacity is around 16 x 30/100.
So it's around five or six Kwh capacity.
No other information needed, everything else is drivel.
So it'll cost £1.50 per charge if electricity costs £0.25/Kwh

On 12/06/2015 08:17, Andy Burns wrote:
dennis@home wrote:

This will take me about 80 miles.

The bike does 120 miles.

It's a single 37¾ mile lap, the superbikes refuel every other lap, how
many years before the electric bikes can do two 130mph laps on a charge?


It does 120 miles at UK legal speeds unlike harry's milk float..

On Thu, 11 Jun 2015 23:10:24 -0700, harry wrote:

A lot of people here don't know the difference between power and energy.
Bad education.

Too true, m8. BTW, did I ever tell you about that time I went on a diet
and lost 7.5 horsepower?

On Fri, 12 Jun 2015 09:08:50 +0100, Dave Liquorice wrote:

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

??
Is this some kind of fancy, metaphysical, existential, hypotheticising
you're indulging in here?

On Fri, 12 Jun 2015 09:40:02 +0100, The Natural Philosopher wrote:

60A trip at 240v is around 144kW... 10 hours at that rate would be 1440
units or at 10p a unit 144 quid give or take.

Sorry, where on earth did you get the 60A trip from??

Cursitor Doom wrote:

The Natural Philosopher wrote:

60A trip at 240v is around 144kW... 10 hours at that rate would be 1440
units or at 10p a unit 144 quid give or take.

Sorry, where on earth did you get the 60A trip from??

He traded it for a decimal point, 144kw my arse!

On 12/06/15 19:53, Andy Burns wrote:
Cursitor Doom wrote:

The Natural Philosopher wrote:

60A trip at 240v is around 144kW... 10 hours at that rate would be 1440
units or at 10p a unit 144 quid give or take.

Sorry, where on earth did you get the 60A trip from??

He traded it for a decimal point, 144kw my arse!

Ooops!

Got some kind of fever to day - sorry.

60A or 100A is generally what a house is rated at on a single phase




--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.

On Thu, 11 Jun 2015 23:10:24 -0700, harry wrote:

On Thursday, June 11, 2015 at 10:44:21 PM UTC+1, Andy Burns wrote:
Tim Streater wrote:

Cursitor Doom wrote:

capable of putting out 160bhp for 37.75 miles

160HP is 120kW, near enough (the distance is irrelevant).

Irrelevant to the power, but not the energy ...

A lot of people here don't know the difference between power and energy.
Bad education is a BBC3 comedy series.


--
Johnny B Good

On Fri, 12 Jun 2015 22:02:36 +0000, Huge wrote:

On 2015-06-12, Cursitor Doom wrote:
On Fri, 12 Jun 2015 09:08:50 +0100, Dave Liquorice wrote:

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

??
Is this some kind of fancy, metaphysical, existential, hypotheticising
you're indulging in here?

Do you not know anything about motorsport?

Who asked you? I'm waiting for some clarification from Mr. Liquorice.

On Fri, 12 Jun 2015 09:40:02 +0100, The Natural Philosopher wrote:

On 11/06/15 22:10, 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

Why. Its correct. Its about what a small windmill puts out in a force 9
gale.


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?

60A trip at 240v is around 144kW... 10 hours at that rate would be 1440
units or at 10p a unit 144 quid give or take.


You cocked up the calculation with a misplaced decimal point. You
obviously meant 14.4KWH. The electricity cost is around 15p a unit (give
or take). If we use your calculations (corrected) and a more realistic
estimate of electricity costs, you'd have been suggesting a figure of
£21.60.

Guessing at about half a 20 litre tank of petrol per lap and estimating
the costs for an electric equivilent coming out at half of that or even
less, I'd estimate the figure may be closer to 6 quid a lap rather than
22 quid.

The highest energy density figure I've seen quoted for L-ion rechargables
(2011 figures) worked out to a mere 240WH per Kilogram. It seems you'd be
looking at 100Kg for a 24KWH's worth of energy storage. A 16KWH battery
would weigh in at about 67Kg.

The electric motors used are tiny compared to the ICE it replaces and a
box of electronics replaces the gearbox. ISTR efficiency figures for
these motors being around the 97% mark (it's simply a specialised
transducer of an energy type that's already in a useful form - no
converting heat energy into mechanical motion at a conversion efficiency
of around 25% or so).

Although battery weights of some 67 to 100 Kg seem a very high price to
pay compared to 18Kg of fuel plus a 2 or 3 Kg tank, the weight penalty is
largely offset by eliminating a heavy ICE and gearbox.

For a single lap time trial 'race' of the 37.75 mile TT course, the
battery weight is a manageable handicap. It's only when we consider
longer races that the ICE power trains win out big time (but even the ICE
powered bikes have to refuel every two laps).

--
Johnny B Good

In article ,
The Natural Philosopher wrote:
Got some kind of fever to day - sorry.

60A or 100A is generally what a house is rated at on a single phase

But doesn't have a 'trip' set at that. Usually a fuse.

--
*If at first you don't succeed, redefine success.

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 13 Jun 2015 09:25:40 +0000, Huge wrote:

On 2015-06-12, Cursitor Doom wrote:
On Fri, 12 Jun 2015 22:02:36 +0000, Huge wrote:

On 2015-06-12, Cursitor Doom wrote:
On Fri, 12 Jun 2015 09:08:50 +0100, Dave Liquorice wrote:

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

??
Is this some kind of fancy, metaphysical, existential,
hypotheticising you're indulging in here?

Do you not know anything about motorsport?

Who asked you?

In which case you should have emailed him, you patronising ****.

I'm most awfully sorry. I didn't realise we had some self-important, self-
appointed moderator here.

On 13/06/2015 10:25, Huge wrote:
On 2015-06-12, Cursitor Doom wrote:
On Fri, 12 Jun 2015 22:02:36 +0000, Huge wrote:

On 2015-06-12, Cursitor Doom wrote:
On Fri, 12 Jun 2015 09:08:50 +0100, Dave Liquorice wrote:

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

??
Is this some kind of fancy, metaphysical, existential, hypotheticising
you're indulging in here?

Do you not know anything about motorsport?

Who asked you?

In which case you should have emailed him, you patronising ****.

You're beginning to sound like Mr Liquorice's faggot.

On 12/06/2015 09:08, Dave Liquorice wrote:
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.

Sometimes there is a grey area in between the two. F1 starting is one
where any number of lights can be on, or even off, yellow flag is another.