Di2 battery not included?

Op 24-8-2012 17:09, Frank Krygowski schreef:
Lou Holtman wrote:

Of course not. He is the only guy I know that buys two exactly the same
bikes. That is the best back up system I know. He doesn't upgrade them
or whatever, just ride the **** out of them en when he thinks they are
worn (5-10 years) he just buys two new ones.

There was an old joke about a rich Texas oilman who would buy a new
Cadillac whenever the ashtray became full...



Hey, he does 12500 km on each bike every year.

LOu

On Friday, August 24, 2012 4:45:32 AM UTC+1, JoeRiel wrote:
Frank Krygowski writes:



Joe Riel wrote:

writes:



On 24/08/12 03:40, Andre Jute wrote:

On Wednesday, August 22, 2012 11:36:11 PM UTC+1, James wrote:



I have enough experience of needing to charge batteries to know my



opinion on the subject.



How compelling was your case? Not at all. Keep trying. --



JS.



As you can see above, I agree that the Shimano's Di2 doesn't need a

battery. But I've recently, after heart surgery, started using the

bike I converted to an electric motor in the space where the hub

dynamo used to live, and I don't find it a chore to recharge the

battery every time I come home, and I've never forgotten. We have so

much crap that we recharge daily (I have a smartphone, a Kindle, an

iPad, a Bluetooth keyboard for the iPad, movie and still cameras, etc

half a dozen or more wires with USB and 30 pin plugs coming over the

corner of my desk) that it has just become a habit.



Unless of course you think it a matter of principle that the bike

liberates you from all that crap — in which case I would understand.





Totally understand the need for assistance, and the fact that you're

still getting out there is best. Your requirement for battery

charging is, well, a requirement.



However all the other items you mentioned (phones, tablets, etc.) you

can do without for a while. A flat battery when you've got 100km to

go on a ride would be less appreciated.



Let's not forget, I'm not saying Di2 (or electronic gear shift in

general) is totally bad. I get the whole self tuning, operate from

multiple positions or automagically pros. All I'm saying is, why make

it require a battery when there is enough energy we can scavenge from

the natural vibrations of the beast we ride to power gear changes for

ever? Free of charge, so to speak ;-)



One problem is getting it started.



Well, with my idea of a magnet in the spokes and a coil on the

chainstay, you'd just spin the wheel a bit. With James's idea, I

guess you'd bounce the bike up and down for a while?



I'm thinking that while the average power dissipation is low

(given the low duty cycle of usage), the energy required to

shift probably isn't insignificant, so you might have to

ride the bike for quite a while before being able to shift.

We need some hard numbers on the energy required.





--

Joe Riel

Hard numbers are always good, but in this case they would be superfluous. I already have enough experience of the full-auto Di2 to know that the amount of current required for the actual shift isn't enough to dim a halogen globe perceptibly. The Cyber Nexus Di2, of which the Dura-Ace Di2 is a much-cut down version, doesn't have a battery, though it does have a capacitor (referred to by Shimano in the literature as "a battery"). The hub dynamo would bring the entire system up within a pace or two (the entire system also including active suspension, and computing power for the speedo and electronic computers, all part of a complete system).

I you have dynamo lamps with standlights, the Di2 Cyber Nexus cap works on the same principle and for about the same length of time. After pushing the bike less than five paces, you could change gears at standstill for about four minutes. Since the cap was probably not very big, that too tells us the amount of current required for gear changes is not much.

Andre Jute

On Thursday, August 23, 2012 7:18:35 PM UTC+1, davethedave wrote:
On Thu, 23 Aug 2012 10:31:56 -0700, Andre Jute wrote:



too broke for all that -- plus I'm a Luddite. I'm sure it will become

the dominant system in five years or sooner -- and I will get trickled

down upon. It's just a matter of time -- like flat screen TVs.



I'm waiting for brains to trickle down...



You may be waiting in vain. I think that they have all trickled down

noses and been blown away already.

--

davethedave

Don't be such a cynic. It may be a long shot but, in physics, it is entirely possible that there is intelligence out there.

Just unlikely...