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  1. 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...
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    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...
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    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...
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    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...
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    Video about how Lithium batteries are born...

    If you ever wanted to make LiIon or LiFePO4 batteries at home, this is for you: :D In short - start making Lithium foil using 400 ton press. It should be uniform 350 microns thick. Then stretch that foil to 30 microns, without tearing it. Don't spill cofee onto the film or it will catch...
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    Aero e-bike concept

    I've been drawing on the backs of the envelopes various ideas of e-bike I'd really want and they began to stabilize somewhat, so here are share them for you to criticize/improve/show that it's really bad design/etc. Criteria that I want are: 1) Have safety cell that would protect the driver...
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    Nissan to sell EVs by 2010

    Hmmm, I'll believe it when I see it. But hey, if this happens, awesome! 500,000 charging stations and mass produced Lithium batteries that charge in 10 mins don't sound too bad. http://www.economist.com/business/displaystory.cfm?story_id=11332425
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    So you wanna short a big battery...

    Yeay! It looks like I have a small contribution for the failed components thread. I'll get the pic soon. But now I'm really puzzled about what happened :| So... I thought, what could be more fun than shorting a big fully charged battery :twisted: The battery is 12Ah, 12V SLA B&B SLA...
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    How to measure inductance

    Guys, What are quick and easy ways to measure inductance of motors or wires? This becomes interesting for power switches (inductive kick), for doing voltage step up if doing regen mod, for resistive spot welder (need low inductance so current can rise fast), etc. Is there any way to do it...
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    Dangerous voltage

    I'm trying to figure exactly what electric shock dangers are in ebike battery packs. Sofar I've found - Danger to humans is from amps not volts. 50mA and up are dangerous. 1mA is when you start feeling tingle - Lots of sites put 50V-60V DC as dangerous voltage. Somehwere I've found that...
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    Update on microcontroller based BMS

    So I've decided to try and build some things based on ideas in this thread: http://endless-sphere.com/forums/viewtopic.php?f=14&t=3486 It went much better than I expected. I'm using Arduino board: http://www.arduino.cc It's unbelievably easy to use. Just download software, plug in usb cable...
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    Another LiFePO4 battery pack on the way

    It looks like finally LiFePO4 are here from a trusted source in North America! ebikes.ca posted an update and they are testing LiFePO4 12Ah batteries right now. I sure hope power tool pack disassembly days will soon be over. http://www.ebikes.ca/
  13. T

    Hybrid battery

    The thread about PIC based BMS got me thinking about connecting different battery types together. Lets make few assumptions for simplicity (those values are based on my measurements, could be way different for you): - Motor controller is 36V 20Amps. - I need to have 8Ah pack for range (that...
  14. T

    Everything about connecting cells in parallel

    Guys, I'm trying to find more info on exactly what happens when cells are shorted together in parallel. General wisdom on the net says: -It's ok to discharge cells shorted together in parallel, all chemistries -It's ok to charge Lithium cells shorted together in parallel - It's not ok to...
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    Anybody made logging osciloscope/voltmeter out of a PC?

    Hello Guys! Could you share how you measure/test/log data about your motors and especially batteries? I'm using watts-up on the bike and voltmeter at home and find this seriously insufficient. What do people use to make those discharge charts for batteries? Ideally I'd love a gadget that...
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    Nimh pack build and test

    With lots of useful advice from this board I've now finished and tested my Nimh pack. I'll post some info that I hope will be useful for others doing the same. Nimh is now the simplest and cheapest option for those not happy with SLA. The Specs: 40 D Nimh cells with tabs 48V 10Ah Weight...
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    Smaller motor

    It looks like crystalyte is the king of diy battery kits. It also looks that their philosophy is bigger is better, which in many cases is just fine. Their 5 series motors have no match in go-fast department if matched to suitable battery. After doing some driving on my 408 i came to realize...
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    Market for battery packs

    The situation with batteries for e-bikes is truly bizare. It's pretty much impossible to buy anything ready to use except SLA. e-bikes.ca stopped selling their Nimh batteries. FalconEv does sell them, but at more than 100% markup for Nimh, and what looks like more than 150% markup for LiMn...
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    Good ride gone bad

    So yesterday I was going to do a long ride to measure full discharge of my batts and other stats. Everything was working great for the first 15 miles until I got a flat, on front wheel with the motor. Considering what a PITA it is to fix it, I didn't even cary spare tube/repair tools. So...
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    Battery comparisson

    I was collecting all info I could find about batteries into a spreadsheet for easy comparison. Attached is my condensed list. I didn’t include anything that’s more than $1/wh, which leaves out most pre-built EV packs. The most interesting battery pack...
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    Crystalyte help

    Hi, I'm an electric bike newbie and just finished installing Crystalyte 408 kit on my bike. Works great and I can't get enough of it! But now I have a bunch of questions and I hope you guys can help me out. I can't find answers to anywhere - I'd like to build 48V battery. It would let me go...
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