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  1. Swordman

    Building a recumbent bike

    Here's a thread on the Long Wheelbase recumbent I built a couple of years ago. It's still pretty much the same but I built a new battery box back in March and went to 3 Milwaukee V28 tool batteries in parallel. I now have over 2000 miles on it and it is still going strong...
  2. Swordman

    Milwaukee battery rack

    Have a look at this thread: http://endless-sphere.com/forums/viewtopic.php?t=233&start=0
  3. Swordman

    A Simpler E-Bike Display

    The model I selected can sense currents up to 100 amps unidirectional. It says it can survive 5x overcurrent conditions. The internal resistance is 100 micro ohms. Here's a digikey link: http://www.allegromicro.com/datafile/0755-100.pdf I've had it up to 26 amps which is about all my system...
  4. Swordman

    A Simpler E-Bike Display

    Thanks. I figured I'd start out by making a printed circuit board of the easy part and then move on to the more complicated part once I got this working.
  5. Swordman

    A Simpler E-Bike Display

    Ok. I have completed the schematic and printed circuit board layout for the sensor unit. I also have created home made circuit boards for the sensor unit using the toner transfer method. The toner transfer method worked well considering this was my first attempt. Attached are some pictures...
  6. Swordman

    A Simpler E-Bike Display

    It could also be where in the circuit you hooked the meter up. I'm hooking mine between the battery and the controller. If you hooked it on the controller-motor side, you would get a lot of pulses instead of a constant voltage and that could be causing your problem. One of my first tests...
  7. Swordman

    A Simpler E-Bike Display

    Thanks, I hope to have it working totally some day. I had the same experience you did. I set up a breadboard in the house here, got it working with a low current draw, and then said, hey this thing works I think I'll build a prototype. So, I built the prototype, put the prototype on the bike...
  8. Swordman

    A Simpler E-Bike Display

    Hi all, I'm getting closer. I just got back from trying a real-world test. Seems to work fine. I got hung up for a while on figuring out why my voltage and current readings were not stable when I went from my breadboard system to my on-bike prototype. I created a sensor unit and connected...
  9. Swordman

    Swordman's Electric Recumbent

    As promised, only a week late, the new and improved Sport Utility Recumbent. $8 Wal-Mart toolboxes can hold a lot of stuff.
  10. Swordman

    Swordman's Electric Recumbent

    Thanks for the compliment. I originally had lead acid batteries above the bottom bar but changed it when I went to NiCad since the battery is so much smaller. I really like everything down low on the bike also. As long as the bike is, it's not like I didn't have plenty of room. :) I...
  11. Swordman

    A Simpler E-Bike Display

    Thanks. It doesn't have all the features of the drain brain. I chose not to implement the regen stuff. I just don't really think you gain that much from regen. Plus, both my bikes have freewheels, so I don't get regen. I may add a cyclometer function in the future. Bike computers are like...
  12. Swordman

    A Simpler E-Bike Display

    Hopefully I'll get there. Right now I actually need to have one that I can test on my bike. Not sure about a $$ figure at this time. The printed circuit board will be the most expensive part. I'm gonna do a proto board first and then move on to a printed circuit board.
  13. Swordman

    A Simpler E-Bike Display

    The meter is set up with four pages, each one may or may not have subpages. The pages are ride, measure, review, and set. The measure page has a subpage that shows volts, amps and watts, and a subpage that shows amp hours and watt hours. The review page has a subpage that shows voltage low...
  14. Swordman

    A Simpler E-Bike Display

    Mathurin: Thanks. I think it is turning out well myself. knightmb: I'll make a better video in the future and may post it to google video then. This one is a first attempt and the quality is not so great at the end. I may sell them in the future, but right now I actually have to get this...
  15. Swordman

    A Simpler E-Bike Display

    Ok, Attached is a video showing the meter in action. Software is basically done and I have 1.5K to spare out of 8K total. Just getting started on the prototype hardware. I've realized that I need a smaller tip for my soldering iron and that my soldering skills have either deteriorated over...
  16. Swordman

    A Simpler E-Bike Display

    They taught us the same. They called it a flow of holes (absense of electrons) flowing from the positive to the negative. Drove my Dad the electronics guru nuts that they were teaching us wrong.
  17. Swordman

    Upload Your Circuit Schematics & Requests Here...

    29a, Check out this thread and see if it is similar to what you are thinking of. http://endless-sphere.com/forums/viewtopic.php?t=367 I'm working on it for myself right now, but may be inclined to sell kits in the future if it works ok. If you have any suggestions for improvement, feel...
  18. Swordman

    A Simpler E-Bike Display

    Well, I just went home for lunch and tried the correct shunt placement. Works like a charm. I just couldn't figure out why when I placed a load across the output my voltage went up. Doh!!!! Reid, thanks for pointing out the obvious.
  19. Swordman

    A Simpler E-Bike Display

    Well, After some spreadsheet engineering and actually using my brain, I believe my whole problem was incorrect placement of the shunt. If I put that in the right place, then the voltage divider should work fine. I kept thinking that the load would affect the voltage divider. But the voltage...
  20. Swordman

    A Simpler E-Bike Display

    Well, it's actually sadder than that. I didn't take high school electronics but I do have a 4 year EE degree. I can caculate voltages and currents and know how the components work and all that, it's just the practical stuff I'm rusty on. Of course, the fact that it's been 20 years since that...
  21. Swordman

    A Simpler E-Bike Display

    Yes, the shunt is on the wrong side. And yes, I would need a 9K resistor for a 10:1 reduction. I currently am using what I have and will need a 40:1 reduction for a max voltage range of 100V which is what I'm after. And I'm equally fuzzy on the practical stuff also.
  22. Swordman

    A Simpler E-Bike Display

    Thanks Reid. It helped some, but I guess a diagram of my test circuit is needed. I have no problem with determining the current. It is simply a matter of measuring the voltage across a shunt resistor and dividing by the shunt's resistance. It is currently 10 ohms for my test setup but will...
  23. Swordman

    A Simpler E-Bike Display

    Yes, I'm still at this. I've come a long way in a few weeks, and am getting close to something that works. Could someone describe how devices like the drain brain and watts up meters measure both current and voltage using a shunt? I can understand how they measure current, just measure...
  24. Swordman

    Ideas for Building an Electric Lawnmower

    Ok, Some more questions. What do you think of a string-line based cutter (like a mounted weed eater) versus a traditional blade? Even though it is more pricey, do you think NiCd or NiMH packs would do the job versus pushing all that lead around or would the amp draw be too much? Although I...
  25. Swordman

    Ideas for Building an Electric Lawnmower

    Thanks lemmiwinks. Nice amount of detail. I'll have to study it for a while. The only question I have right now is your choice of motor. I seem to remember you had the MY1020 lying around and you used what you had. Do you think a smaller motor could would work ok, or do you think 500W is...
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