#91
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On 3/11/2017 7:38 AM, Joerg wrote:
On 2017-03-10 19:40, Sir Ridesalot wrote: On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote: Snipped With or without dynamo I'll never ride without a battery because then it's lights out when waiting at an intersection. Very bad at night. Now, about the bicycle air conditioner ... :-) -- Regards, Joerg http://www.analogconsultants.com/ Most decent dynamo ights these days have a standlight that'll run for several minutes when the bicycle is stopped. I have seen that in Germany. Standlight was very dim though. I prefer it to be lit normal like it is on my bikes. On one of my dynamo lights the light automatically dims to extend the duration of the standlight. On another it does not dim and it stays lit for only a very short time. |
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#92
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On 13/03/17 01:57, Joerg wrote:
On 2017-03-11 16:28, Sir Ridesalot wrote: You need to look again at more modern stuff because many dynamo hub standlights are quite bright for the time they stay on usually a ferw minutes or so if needed. But then again absolutely NOTHING ever works for you off the shelf. Wrong, it does and I have written about it here in the NG. I bought a Cree XM-L based light each for the road bike and the MTB. Of course, since almost nothing in the world of cycling is very robust or complete this had to be spiced up. Both lights got diffusor lenses because they will otherwise blind others and the light distribution wasn't to my liking. Big deal, you just buy diffusor lenses and install them. Then the battery holders are lousy. This took a little more work but nothing that can't be done with a trip to the hardware store and basic hand tools: http://www.analogconsultants.com/ng/bike/Battbox2.JPG You just proved Sir's point. Well done Joerg. -- JS |
#93
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On Sunday, March 12, 2017 at 7:57:46 AM UTC-7, Joerg wrote:
On 2017-03-11 16:28, Sir Ridesalot wrote: On Saturday, March 11, 2017 at 10:38:39 AM UTC-5, Joerg wrote: On 2017-03-10 19:40, Sir Ridesalot wrote: On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote: Snipped With or without dynamo I'll never ride without a battery because then it's lights out when waiting at an intersection. Very bad at night. Now, about the bicycle air conditioner ... :-) -- Regards, Joerg http://www.analogconsultants.com/ Most decent dynamo ights these days have a standlight that'll run for several minutes when the bicycle is stopped. I have seen that in Germany. Standlight was very dim though. I prefer it to be lit normal like it is on my bikes. -- Regards, Joerg http://www.analogconsultants.com/ You need to look again at more modern stuff because many dynamo hub standlights are quite bright for the time they stay on usually a ferw minutes or so if needed. But then again absolutely NOTHING ever works for you off the shelf. Wrong, it does and I have written about it here in the NG. I bought a Cree XM-L based light each for the road bike and the MTB. Of course, since almost nothing in the world of cycling is very robust or complete this had to be spiced up. Both lights got diffusor lenses because they will otherwise blind others and the light distribution wasn't to my liking. Big deal, you just buy diffusor lenses and install them. Then the battery holders are lousy. This took a little more work but nothing that can't be done with a trip to the hardware store and basic hand tools: http://www.analogconsultants.com/ng/bike/Battbox2.JPG Why would I want inferior light when I can have a Cree XM-L that affords me almost the same quality light as a motorcycle has? This light doesn't just offer a few minutes of "standlight", it offers north of five hours of light at full blast, whether the bike move or not. I also have a power outlet on the bike. Hmm, I've managed without a battery box, outlet and motorcycle light on a road bike for like 50 years. I was riding up and down narrow canyons and city streets today without so much as a blinky. The one car that pulled out in even a semi-perilous fashion did so while looking straight at my son and me. No question of our location on the road. I get cars doing the same thing when I'm in a car. They think they can beat you into traffic. -- Jay Beattie. -- Jay Beattie. |
#94
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jbeattie wrote:
On Sunday, March 12, 2017 at 7:57:46 AM UTC-7, Joerg wrote: On 2017-03-11 16:28, Sir Ridesalot wrote: On Saturday, March 11, 2017 at 10:38:39 AM UTC-5, Joerg wrote: On 2017-03-10 19:40, Sir Ridesalot wrote: On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote: Snipped With or without dynamo I'll never ride without a battery because then it's lights out when waiting at an intersection. Very bad at night. Now, about the bicycle air conditioner ... :-) -- Regards, Joerg http://www.analogconsultants.com/ Most decent dynamo ights these days have a standlight that'll run for several minutes when the bicycle is stopped. I have seen that in Germany. Standlight was very dim though. I prefer it to be lit normal like it is on my bikes. -- Regards, Joerg http://www.analogconsultants.com/ You need to look again at more modern stuff because many dynamo hub standlights are quite bright for the time they stay on usually a ferw minutes or so if needed. But then again absolutely NOTHING ever works for you off the shelf. Wrong, it does and I have written about it here in the NG. I bought a Cree XM-L based light each for the road bike and the MTB. Of course, since almost nothing in the world of cycling is very robust or complete this had to be spiced up. Both lights got diffusor lenses because they will otherwise blind others and the light distribution wasn't to my liking. Big deal, you just buy diffusor lenses and install them. Then the battery holders are lousy. This took a little more work but nothing that can't be done with a trip to the hardware store and basic hand tools: http://www.analogconsultants.com/ng/bike/Battbox2.JPG Why would I want inferior light when I can have a Cree XM-L that affords me almost the same quality light as a motorcycle has? This light doesn't just offer a few minutes of "standlight", it offers north of five hours of light at full blast, whether the bike move or not. I also have a power outlet on the bike. Hmm, I've managed without a battery box, outlet and motorcycle light on a road bike for like 50 years. I was riding up and down narrow canyons and city streets today without so much as a blinky. The one car that pulled out in even a semi-perilous fashion did so while looking straight at my son and me. No question of our location on the road. I get cars doing the same thing when I'm in a car. They think they can beat you into traffic. You gotta love the way he starts out telling Sir that Sir is wrong and then doing exactly what Sir said that he does. :-) I seem to get by with off the shelf equipment though I readily admit that I haven't seen a mountain lion in ages. -- duane |
#95
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On 2017-03-12 13:26, sms wrote:
On 3/10/2017 4:52 PM, Joerg wrote: With or without dynamo I'll never ride without a battery because then it's lights out when waiting at an intersection. Very bad at night. I've been doing a lot of design with Li-Ion batteries lately and I realized that a dynamo is almost a perfect match for two series Li-Ion batteries when I was helping a colleague charge his Magicshine pack with a lab supply set to 8.4VDC. Think of a dynamo putting out 6VAC, with a full wave Schottky rectifier you'll get about 8V (8.4V - 0.4V of voltage drop. 8V is just about right to charge two series Li-Ion batteries. Just in case of high speed riding, stick in an VLDO like a LT3022 with 145mV drop and you're at 7.855V, still enough to get two series Li-Ion cells to full capacity. The losses are very low, even lower than a switcher. If I ever have a hub dynamo I'd use a buck and use a 2nd loop to control it. The 1st loop would cut the charge if 8.2V has been reached. The 2nd (inner) loop would set the input voltage to the point where maximum power is achieved. At the usual brisk ride that most if not all people in this NG are capable of that voltage level will more likely be well north of 10V. A dynamo is essentially a current source where you can let the voltage scoot up until a point is reached where the current drops off so much that the total power begins to drop. Like MPPT for solar generation. The reality is that with protected Li-Ion cells you don't even need the VLDO since the batteries are protected from charging over 4.2V per cell. That's how some cheap Chinese chargers work. Not good as that is no lomnger single-fault safe. It is as if you'd control a pump via tripping a GFCI when a certain fill level has been reached. At lower output levels, a dynamo could even run a 2 cell battery powered light if the batteries were removed. Then you'd be back to this inferior dynamo lighting which goes out at the traffic light, or uses dimmed or short-lived light if there is a supercap installed. -- Regards, Joerg http://www.analogconsultants.com/ |
#96
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More About Lights
On 2017-03-12 13:28, sms wrote:
On 3/11/2017 7:38 AM, Joerg wrote: On 2017-03-10 19:40, Sir Ridesalot wrote: On Friday, March 10, 2017 at 7:52:30 PM UTC-5, Joerg wrote: Snipped With or without dynamo I'll never ride without a battery because then it's lights out when waiting at an intersection. Very bad at night. Now, about the bicycle air conditioner ... :-) -- Regards, Joerg http://www.analogconsultants.com/ Most decent dynamo ights these days have a standlight that'll run for several minutes when the bicycle is stopped. I have seen that in Germany. Standlight was very dim though. I prefer it to be lit normal like it is on my bikes. On one of my dynamo lights the light automatically dims to extend the duration of the standlight. On another it does not dim and it stays lit for only a very short time. Yeah, all they've usually got is a supercap of a few Farads. There is only so much energy to go around, you can either achieve a dim light or a longer duration but not both. -- Regards, Joerg http://www.analogconsultants.com/ |
#97
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On 2017-03-12 15:21, James wrote:
On 13/03/17 01:57, Joerg wrote: On 2017-03-11 16:28, Sir Ridesalot wrote: You need to look again at more modern stuff because many dynamo hub standlights are quite bright for the time they stay on usually a ferw minutes or so if needed. But then again absolutely NOTHING ever works for you off the shelf. Wrong, it does and I have written about it here in the NG. I bought a Cree XM-L based light each for the road bike and the MTB. Of course, since almost nothing in the world of cycling is very robust or complete this had to be spiced up. Both lights got diffusor lenses because they will otherwise blind others and the light distribution wasn't to my liking. Big deal, you just buy diffusor lenses and install them. Then the battery holders are lousy. This took a little more work but nothing that can't be done with a trip to the hardware store and basic hand tools: http://www.analogconsultants.com/ng/bike/Battbox2.JPG You just proved Sir's point. Well done Joerg. Huh? I made it quite clear that my solution works. It does very well. -- Regards, Joerg http://www.analogconsultants.com/ |
#98
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On 3/13/2017 11:06 AM, Joerg wrote:
snip That's how some cheap Chinese chargers work. And a lot of non-Chinese chargers as well. Not good as that is no lomnger single-fault safe. It is as if you'd control a pump via tripping a GFCI when a certain fill level has been reached. Technically there are two safety circuits. First, with an 8.4V output charger you're limiting the charging voltage to 4.2V per cell. Second, the protection circuit on each battery, or on the battery pack, limits the voltage to 4.2V per cell just in case someone plugs in a higher voltage charger. I think the simplest dynamo to Li-Ion 2S pack circuit would consist of only three parts. A 2A Schottky bridge. A filter cap. An 8.2V, 5W zener diode. I don't think you even need a current limiting resistor because the dynamo isn't going to put out much more than 500mA. I don't think you gain much with a buck switcher unless you're often putting out dynamo voltage well in excess of 6VAC, or unless you want to do 5.25V for USB charging. You're going to lose some power with the switcher which is likely to be only 85%-90% efficient. You could stick in a Murata LXDC55FAAA-203 http://power.murata.com/data/power/LXDC55FAAA-203_data_sheet_E.pdf instead of the zener and do a USB version also with only three parts. But I know that you love designing your own switchers. I'm in shock when I see the prices of some of these dynamo to USB adapters, since the parts cost is only a few bucks. http://www.sinewavecycles.com/products/sinewave-revolution Here's someone that did it DIY but using a linear regulator. http://www.14degrees.org/diy-bicycle-dynamo-usb-charger-for-smartphones-and-battery-packs/ At lower output levels, a dynamo could even run a 2 cell battery powered light if the batteries were removed. Then you'd be back to this inferior dynamo lighting which goes out at the traffic light, or uses dimmed or short-lived light if there is a supercap installed. No, I'm more thinking of a way to have a good light but with dynamo back-up should the batteries go flat. As well as charging the batteries during daytime riding when all you're using is the DRL flash mode. Unfortunately, since dynamo lights are so rare in the U.S. we end up with sub-standard lighting with poor beam patterns, low intensity, no flash mode, and inferior brightness when stopped or riding slowly. I thought it was interesting that Barry Beams mentioned that his light could work, at less than full intensity, off of dynamo output. He may have a compelling product for dynamo users that want a brighter, safer, light but that still want the assurance of not being caught out with flat batteries. Even Frank realized the need for better lights and bought an Oculus. And while the Oculus may not be a bargain battery powered light (even though the price is still pretty reasonable), it's a lot less than dynamo lights that are not as good. |
#99
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More About Lights
On 3/13/2017 3:14 AM, Duane wrote:
I seem to get by with off the shelf equipment though I readily admit that I haven't seen a mountain lion in ages. Come to Cupertino. http://www.mercurynews.com/2016/06/05/mountain-lion-prompts-park-evacuation-near-cupertino/ A multi-use trail goes right through there. |
#100
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More About Lights
On Mon, 13 Mar 2017 11:06:18 -0700, Joerg
wrote: A dynamo is essentially a current source where you can let the voltage scoot up until a point is reached where the current drops off so much that the total power begins to drop. Like MPPT for solar generation. Not exactly a current source. More like a resistor (coil resistance) in series with an easily saturated inductor[1]. The problem is that the bicycle dynamo operates over a range of frequencies, while the typical solar charge controller operates at a fixed frequency. The inductive reactance of the dynamo winding appears at variable series resistance that increases as the dynamo goes faster. There are also substantial differences in operating frequency between bottle and hub dynamos: http://www.pilom.com/BicycleElectronics/HubDynamo.htm "Hubs rotate at a much lower frequency than bottles, and though they have more poles to somewhat compensate, they still end up delivering a much lower frequency. At 15 km/h, the B&M Dymotec6 bottle dynamo (8 poles) outputs 168 Hz AC while the Shimano DH-3D71 hub dynamo (28 poles) outputs only 28 Hz at the same speed. At 8 km/h, a 28 pole hub is down to 15 Hz, which causes visible flicker of the light" Also, the dynamo iron and number of turns are selected so that the dynamo saturates at some point near the operating speed and load. The idea is not so much to regulate the AC output, as it is to reduce mechanical resistance at higher RPM's. I tried to build an LTSpice model that simulated a real dynamo and failed. I couldn't make it act like my bottle dynamo bench tests and various online graphs. Maybe I'll try again this week. I'm suppose to be on a (medical) vacation right now. [1] SON dynamo driving MOSFET bridge: https://www.flickr.com/photos/kurtsj00/8480800746/in/photostream http://www.candlepowerforums.com/vb/showthread.php?355392-Spice-code-for-dynamo-output The author uses 0.1Hy in series with 2 ohm at 30 Hz. When I swept the 30 Hz over a 10 to 50 Hz range, it didn't look much like a dynamo. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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