Dynamo math

"sothach" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

On the subject of lighting and stuff, I was trying to figure out how
much my lighting costs me to operate. According to my sums, it's
something like 4kCals per hour, based on the SON dynamo having 65%
efficiency and running a 3W lamp - can that be right? That's about two
peanuts: very cheap power.

Can you tell the difference with the light on vs light off? It's tiny, so
yes, your sums are probably right.

cheers,
clive

In news:[email hidden],
sothach <[email hidden]> typed:

Quoted message said:

On the subject of lighting and stuff, I was trying to figure out how
much my lighting costs me to operate. According to my sums, it's
something like 4kCals per hour, based on the SON dynamo having 65%
efficiency and running a 3W lamp - can that be right? That's about two
peanuts: very cheap power.

That would be if you where 100% efficient.

--

Geoff

sothach said:

On the subject of lighting and stuff, I was trying to figure out how
much my lighting costs me to operate. According to my sums, it's
something like 4kCals per hour, based on the SON dynamo having 65%
efficiency and running a 3W lamp - can that be right? That's about two
peanuts: very cheap power.

You should probably factor in the depreciation on your SON unit.

--
Dave...

dkahn400 said:

sothach said:

On the subject of lighting and stuff, I was trying to figure out how
much my lighting costs me to operate. According to my sums, it's
something like 4kCals per hour, based on the SON dynamo having 65%
efficiency and running a 3W lamp - can that be right? That's about two
peanuts: very cheap power.

You should probably factor in the depreciation on your SON unit.

Come to that, your own depreciation >🙂

sothach said:

On the subject of lighting and stuff, I was trying to figure out how
much my lighting costs me to operate. According to my sums, it's
something like 4kCals per hour, based on the SON dynamo having 65%
efficiency and running a 3W lamp - can that be right? That's about two
peanuts: very cheap power.

That's not cheap power.
Mains electricity is about 10p per kilowatt-hour, so a 3W light would
cost 0.03 p/hour to run.
Say a bag of peanuts is 50p for 100 nuts, that's 0.5p/nut, so 1p to run
your dynamo.
So peanut power is about 30 times as expensive as the mains.

POHB said:

sothach said:

On the subject of lighting and stuff, I was trying to figure out how
much my lighting costs me to operate. According to my sums, it's
something like 4kCals per hour, based on the SON dynamo having 65%
efficiency and running a 3W lamp - can that be right? That's about two
peanuts: very cheap power.

That's not cheap power.
Mains electricity is about 10p per kilowatt-hour, so a 3W light would
cost 0.03 p/hour to run.
Say a bag of peanuts is 50p for 100 nuts, that's 0.5p/nut, so 1p to run
your dynamo.
So peanut power is about 30 times as expensive as the mains.

A cyclist would need an awfuly long lead. The cost of the flex should
be factored in. What about power loss in the long lead? Public
liability insurance against trip hazard?

Quoted message said:

A cyclist would need an awfuly long lead. The cost of the flex should
be factored in. What about power loss in the long lead? Public
liability insurance against trip hazard?

You could say the same for peanut stalks. Fortunately you can detach
peanuts from the plant and put them into a portable container, the same
as you can with mains power.