Search results

Date Relevance Most replies

  1. T

    Sony Camcorder Li-ion batteries

    I'll just make a case for those batteries. Unfortunately I didn't try this setup myself yet, but looking for good deal and will do so. Tesla car uses such cells (high energy, low power). The idea is that they are cheaper and have double the capacity than similar tool pack cells. So assume...
  2. T

    LED lighting question

    1w led is more of a "be seen" than "see the road" type. it will not compare to bicycle halogen setup. if your old halogen setup was mr16 type - there are led mr16s that fit. they work off 12v and provide up to 3w of light. I found those convenient, cheap and easy to use. 2x led 3w mr16 are...
  3. T

    new Scorpion motors and controllers

    OMG! I have drool all over my keyboard. To put this in perspective: 5545 has 4.5kw/kg Best aircraft engines are about 1kw/kg (Rotax 912) without necessary fluids Crystalyte 408 is 7kg about 1kw so 0.14kw/kg This motor has more than 30 times better power density than best hub motors.
  4. T

    Motorcycle class Hub Motor

    Hi Mark, That's very exciting! I would buy a motor that would fit bikes like Honda Innova or Sachs MadAss. I'll also keep the motor under 4kw peak as to stay within EU regulations for mopeds. For me a Crystalyte X5 would work perfectly, but it would need to be laced to motorcycle rim...
  5. T

    bak a123

    They used to make cells for A123 up until 2007 but no longer do. This is related to them being sued by Hydro-Quebec for patent infringement together with Black&Decker and A123. They do not manufacture high discharge cells at this point of any kind, but plan to. You can read it all in all gory...
  6. T

    Headlight build and comparisson

    Side illumination now is surprisingly good, similar to the halogen car light. Lens rated for 30 degree angle actually throws lots of light to the sides too. I'm not sure how they rate them. The problem with doing a nice closed case is heat. Even now, everything open, heat is borderline...
  7. T

    Headlight build and comparisson

    Next steps will be to waterproof this one and to build rear light out of red 1W leds. I'm undecided if I should use lenses for them or not. Should I keep leds covered with clear or diffuse glass? The goal is to achieve maximum visibility. Any ideas?
  8. T

    Headlight build and comparisson

    Now for the 3x 3W light build. Parts are: 3x 3W white star leds 2x 10 degree lenses 2x 30 degree lense PowerPuck buck converter Milwaukee V18 lithium tool battery 3mm x 25mm aluminum bar 1mm think aluminum foil Heat sink grease Assorted wires and screws The key to making it work is heat...
  9. T

    Headlight build and comparisson

    Now a comparison. All pictures are of the same view, taken with the identical camera settings but different lights on. Camera was set to f/3.5, 1/60s, iso 1600, 28mm equiv lens. So view is pretty wide. 1) 1W Catye Led. Very narrow angle of view and pretty much not much light at all 2) 3W...
  10. T

    Headlight build and comparisson

    I've built myself a nice 10W led headlamp and did some quick tests. I spent quite some time doing wrong things, so hopefully this will be a useful recipe for those who are thinking to make something similar. Also here is a quick comparison with a bunch of other lights. Background. I've been...
  11. T

    New High Rate LiMn cell from Panasonic

    Forgot one vendor. Valence batteries are used in mass market product (Segway), and they do sell their battery packs in useful capacities, with BMS and robustly packaged. But they are VERY expensive.
  12. T

    New High Rate LiMn cell from Panasonic

    The situation with lithium batt sucks. But while we keep waiting you might enjoy reading what I found out about this. Skip the rest of the post if you look for any useful info, it's just for amusement. LiMn is as safe as LiFe. They won't explode or catch fire if impaled by nail, heated etc...
  13. T

    backup power pack - 24v, 4ah+

    You actually don't need to build anything. Milwaukee V28 batteries give exactly the same voltage as charged 24v lead batteries. They are 3Ah, 84Wh. That should give a range of 4-8 miles. Standard charger will charge in 1 hour (or you can charge for 15 mins and have range of 1-2 miles)...
  14. T

    What the big guys pay

    I'm sorry that my post sounded like an attack on dedicated pack sellers. It's certainly great that some people serve e-bike industry whatever the price. I'm not saying the sellers mark up the prices My point is this: Lithium producers sell packs for $0.5/Wh I can buy for $2/Wh. So the...
  15. T

    What the big guys pay

    Here's an interesting snippet in the news: http://www.autobloggreen.com/2008/08/26/enerdel-ramping-up-battery-production-to-supply-th-nk/ Th!nk has ordered $70 million worth of battery packs from EnerDel, which equates to about 5,000 units. Each pack contains about 27 kWh of power. So, that's...
  16. T

    20 million e-bikes sold in china last year

    Actually article linked in fifth post here pretty much answers what kind of stuff they have. Check out for example http://www.wettsen.com.cn/ (High end manufacturer in China). Not very exciting: Lead-Acid Brushed Motors 85Lbs total weight 12mph speed limit (legal requirement there) Average...
  17. T

    20 million e-bikes sold in china last year

    Economist article is a really brief: http://www.economist.com/daily/chartgallery/displayStory.cfm?story_id=11879821&source=features_box4 For comparison in US 15 million cars and about 12 million bicycles were sold that year. This is really huge number. E-bikes must be mass-market there. I...
  18. T

    Charger/Regen/Regulator all in one

    Guys, I've been thinking about something for e-bikes that Tesla/AC Propulsion cars have. Wouldn't it be nice to have a device that: - Steps up/regulates battery voltage. Your pack could live at 41-25V and regulator would boost it to constant 72V - Regenerates bracking energy and recycles it...
  19. T

    A PIC based Battery Management System

    My own project to build BMS ended at the security checkpoint in the airport. The comment was "now this looks like a bomb!". I got dragged through every imaginable search and check and lost my two precious Arduino boards + all circuits I've built. Apparently I'm lucky to not have been charged...
  20. T

    Press report on Li-On bats production growth in China

    The source for that snippet is: http://www.ipd.anl.gov/anlpubs/2008/02/60978.pdf It's an 80 page long aggregation of google search results about batteries. Summaries of unverified data from company web sites, press releases, 5 year old statistics. Frustrating read, but has some tiny bits of...
  21. T

    another must see new ev very cool

    Electric motors are so perfect for gliders ultralights that I think you will not find pure gliders in a few years. Some approximations Glider gross weight: 500kg (300 glider, 100kg pilot, 100kg motor/batteries) Glide ratio: 1:40 Energy needed to climb to typical tow altitude of 1000 meters...
  22. T

    Aero e-bike concept

    BMW C1 crash tests show what is possible in terms of safety. Actually I think C1 was almost perfect platform for electrifying. Too bad the concept didn't catch on. I think the problems were more mismanged manufacturing and marketting rather than technical. zLP0PxZkJPg
  23. T

    Aero e-bike concept

    Papa, what you say is true. I ride my bike every day to the subway stop, and it has no crash protection. Non electric version can't have any, because it would be too heavy to pedal. So we're stuck with it. My subway stop has probably few hundred bikes parked in the morning. Both I and many of...
  24. T

    Multimeter Recommendation

    I bought Fluke with a bit of a guilty feeling. It cost 100+ and there are $20 multimeters that look the same on spec. Now that I have it and use it I think price difference is justified. I Mine is Fluke 117. Here's why: - Amazing ergonomics. Noodle wire probes with comfy grips. Soft shell...
  25. T

    Aero e-bike concept

    Yep, aero-velomobiles have been arround for some time. Another one that was specifically designed to be aero is Quest. In my opinion all of them are pretty horrible designs, for the following reasons: - No safety cell. That ultralight fairing will be as good as being hit on bicycle - You...
Back
Top