Hi Howard,
Yes! I'll surely post on how the PAT works out. It should arrive within a week, and then the old wiring has to be replaced with the new and then some instrumented test rides will follow.
...my feeling is you need to be going over 30kmh to get it to start charging at all when lights are on. Am wondering if the PAT will help with this...
If TT's claims and chart are acurate, it should.
It is supposed to address the very situation you describe -- when a high-draw/high-drain gadget is connected to the Plug2, it sometimes pulls more current than can be supplied
during operation at a reasonable speed. Supposedly, the PAT lowers the speed where appropriate power is produced.
Without the PAT (or if it doesn't fulfill its claimed benefits), one can still plug in and charge such thirsty gadgets, but they must be in a turned-off state or the charging can't keep up with demand. It would also help if they didn't have to be recharged from flat. A topoff will bring better results.
With or without the cord, I wouldn't
expect to power
and charge a high-draw device with the lights on. Whenever the power is split between lighting and charging, the charging will at least take longer. If the PAT makes it possible to get reasonable charging speeds with the lights on, so much the better!
During daytime, with no lights, I seem to be getting charging OK at somewhere between 15 and 20 kmh - it's difficult to know exactly, but is definitely below 20
This sounds about right, Howard. I'm finding the green "Charging OK" light comes on solid at about 8-12kph
with no load attached. Watch the TTTP2 green LED carefully; it will blink of the gadget demands more juice than it can supply. It shows up pretty well outdoors, but may require a little hand-shade to see on a bright sunny day.
Howard, there's some basic problems when charging devices by bicycle:
- The dynohub's output increases with speed.
- To prevent damage to the device being charged, the charging adapter (The Plug2, in this case), must rectify the current from the dynohub's AC to DC.
- To prevent damage to the device being charged, the charging adapter (The Plug2, in this case), must regulate the voltage and current produced by the dynohub.
- In the case of The Plug2, the voltage and current are rectified and regulated to USB standards, which are a nominal 5vdc@500ma.
To keep things in perspective, 500milliAmps is the same as .5Amps.
To convert amps to watts, use the formula below:
P=IE (Power = Current * Voltage)
P=(0.5)E
Plug in the value of E and you will get P
Walking through it, we have .5A x 5 volts = 2.5/.5 = 1.25 watts <-- 1.25 watts isn't much. Seeing it reported as watts kinda keeps the output in perspective.
Now, here's the dirty little secret of USB devices: A USB plug or socket may look identical, but how much current is produced or drawn varies dramatically. Most people will notice their iPhones charge a lot faster when plugged into the dedicated charger than when plugged into their computer's USB socket. The iPhone has a specified range of current it will accept, and while it
can charge on a computer USB port, it will charge
faster on the high-output provided by its dedicated charger. The same is true of many devices, and will become ever more true as gadgets become more power-hungry. Yes, they may be able to trickle-charge on computer-standard USB power, but charge *and* run? Eh, mebbe not.
Here's the deal:
- When attached to a dynohub, The Plug2 puts out a computer standard USB 1.1 or USB 2.0 output, so let's look at that. USB 1.1 and 2.0 are the same, supplying 5v at 500mA. There is a little tolerance allowed, so the actual range in *voltage* may vary from 4.5vdc to 5vdc. The standard for USB 3 is 900mA; USB 3 allows backward compatibility, faster data transfer *and* higher power output, but at this time is fairly new, so we're pretty well stuck with USB 1.1/2.0 *output* standards for now. Now, here's the thing: Not all computers can put out the same amount of power, and laptops are often among the worst in reaching consistently high standard output. The second part of this is not all computer ports on a given machine have the same output, as the power is often split from a main supply. And, sometimes, the manufacturer includes extra USB ports for convenience sake, not because they think a person will use them all at once. I tested a couple netbooks recently, and voltage at the USB ports could drop to as low as 3.3vdc when multiple devices were plugged in. Their power supplies aren't terribly robust because they generally don't need to be. To get enough power to run things like portable external hard drives, most such gadgets include a second USB cord so the supply power can be combined. That pretty well sums up a thumbnail sketch of the supply side.
- Now, here's the consumer side: Gadgets are designed/programmed for a range of power consumption and to tolerate a range in supply power. Many require more power to charge-from-flat-dead than they do to top-off. While many will tolerate a computer-standard USB output for trickle-charging, they are really designed for use with a supplied higher-output, dedicated mains adapter. Given this, one can't really expect the same results when plugging a high-drain/draw gadget into a computer-standard USB socket, whether it be on the computer or The Plug2.
A Danneaux prognostication: The Plug3 will operate on USB 3 standards and produce 5 volts at 900mA. It's commmminnnng.... It almost has to. And yes, it will probably require buying a new Plug, since I don't think the existing circuitry can be boosted to those levels with a wiring adapter like the PAT. Time will tell.
Added to all the above, not all gadget makers adhere to USB wiring standards. Garmin is one such, and it means adapting an OEM cable or making one's own. iPhones can be problematic with some chargers for this very reason, though it seems to be compatible with The Plug2. There is sometimes the opposite case where a device can be damaged by too much power; that's why gadget manufacturers sometimes issue cautions about not using their devices with other chargers.
One has to be really mindful of the wire used in the adapter cords, as well, as that can account for considerable voltage drop due to variations in electrical resistance.
Not all USB connecting-cords are equal! I can't emphasize that enough. Even a poor solder connection can make a significant difference, and most USB connector connections are sealed, so you can't readily view them (a digital volt/ohm multimeter will quickly become your friend). Get a "bad" connecting cord/adapter, and it will compromise the charging of any device plugged into the system.
If one wishes to delve more deeply into USB power standards, two really good starting points for beginners are:
http://en.wikipedia.org/wiki/Universal_Serial_Bus...and...
http://www.extremetech.com/computing/115251-how-usb-charging-works-or-how-to-avoid-blowing-up-your-smartphoneit will be a pain to install
Howard, I share your pain! If you can substitute the Tout Terrain expander plug at the top, it will help at that end. It won't help at the bottom, due to the butting at the bottom of the steerer -- it makes for a smaller inside diameter. Removing a star-fangled nut is not as hard as it seems. See my post here for an easier method:
http://www.thorncycles.co.uk/forums/index.php?topic=3800.0 Is there another way than a SFN to mount the headlights? Could they instead clamp to the handlebars or a fork leg or perhaps mount to the fork crown?
[EDIT: How 'bout using an expanding, plastic handlebar plug? Either lathe-turn it down in diameter, or carve on it or sand it down. Saw or Dremel a kerf in the side of the expander and plug, and you should have a good substitute for the lower SFN so you can still mount your lights, but with less hassle.]
Having just gotten my wiring buttoned-up to perfection, I'm a bit reluctant to mess with it myself. Thorn (thoughtfully!) mount a plate across the bottom of the steerer and thread it in two places to mount the front fender. That plate leaves little clearance on each side for snaking connectors through (and one has to have that clearance to allow for eventual headset replacement, for example). I may use a Dean's connector (Model 2NB, P/N 1002/1225
http://www.wsdeans.com/products/plugs/micro_plug.html ) with the existing lower wiring. Boom, done. And, it would ease future service.
You asked...
Do you know how it is secured in the steerer tube? Or does it just hang and bang about?
Good question! I think it just slides into the steerer, held by the extra length of the lead wire stuffed in around it. I'm a bug about having no rattles on the bike, and this worried me about the TTTP2, but so far no noise with the extra lead wire doubled over itself in the steerer. I don't think the PAT has much mass, and will be problem-free. Yes, it will almost have to hang from The Plug's power connector. <-- That's the part that has me worried. TT say you can simply pull it apart with firm pressure, but I am worried. Mess that up and it would be an expensive venture.
This whole idea of generating one's own power when riding is still in its infancy and requires learning a bit before jumping into the deep end of the pool. Standards and requirements are changing by the day, and so much depends on which gadget you decide to charge. It is hard to approach the whole idea purely from a consumer standpoint. While almost any setup will produce a minimal charge, I have concluded one must be either a) somewhat lucky or b) resigned to becoming a Junior Engineer in order to get the
best results. Use will also require some discipline and planning. I think I will have to learn to keep an eye on my batteries while on-tour, and top-off as necessary. It looks like I will have to budget about 2.4 hrs per AA battery for charging, which means about 5 hours per pair, and 10 hours for a set of four (day's riding = one complete set of batteries charged from flat). I have found batteries make a huge difference (more on that in another post) and so does adapter lead wire gauge and electrical resistance, but that is a topic for a future post as well.
Best,
Dan.
