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  1. battman

    Temperature monitoring project

    Overview This project provides reliable and scalable monitoring of temperatures through one or more digital sensors with results shown on a 4 digit LED display. The initial implementation has been used to monitor temperature at 12 points within an existing battery pack. Usage On power up, the...
  2. battman

    Barron Greig's Throttle Remapper

    Thanks. I chose that chip because it's cheap and easy to program via it's high level Basic language support. Even using Basic, the performance is more than sufficient for this application.
  3. battman

    Barron Greig's Throttle Remapper

    Hi Folks, This thread describes a circuit to take the signal voltage from a 5V throttle and remap that voltage under software control of a Picaxe chip. I have an electric bicycle with a Grin Technologies Phaserunner V2 with a single throttle providing both drive and regen braking. With this...
  4. battman

    DP-Ninja 8000W 72V 100MPH

    It will not achieve 100mph on flat ground, in still conditions, with 8000W. That would require at least double that power. Perhaps they mean it is rated at 8000W continuous with much higher peak power available, but they don't make that apparent in the specs and even if that is the case, that...
  5. battman

    Michael Czysz

    I only saw this just now http://lanesplitter.jalopnik.com/visionary-motorcycle-designer-racer-michael-czysz-pass-1775647380 Very, very sad. This guy was a wonderful, inspiring visionary.
  6. battman

    Refrigerating electric car batteries?

    +1 on the insulation if you can take your pack indoors on a hot day after riding. I live in Phoenix and have a 36Vx15AH pack inside an aluminum box that I insulated to protect the cells against vibration and shock. Turns out that this insulation has a significant added benefit for limiting...
  7. battman

    Barron Greig's MAX14920 Based Perfboard BMS

    Ha, yes it is ugly. Maybe a coat of paint would help? :lol: I'm done with the initial version of the windows and MCU coding, links to the source code for both are in the post. But I'm still open to bug fixes/ improvements of course. I may take you up on your very kind offer of help...
  8. battman

    Barron Greig's MAX14920 Based Perfboard BMS

    Hi Folks, Motivation for this project was similar to the MAX11081 BMS I put together last year (http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=56937&p=849127&hilit=max11081#p849127), namely bad experience with commercial BMS and looking for something simple enough that I could build...
  9. battman

    light batteries with low AH, or heavy batteries with high AH

    For the lead acid, 120AH at 60lbs would be 53Wh/Kg which is not a credible energy density for this type of battery even under "ideal" conditions (e.g. discharging at one milliamp at 25 Celsius).
  10. battman

    ??:38120 Lifepo pack,36V,only reads 40.3V fully charged

    There isn't necessarily anything wrong with the pack. I've seen the same behavior after charging on packs I made from both A123 20AH cells and Headway 40152 cells. In both cases I still had full capacity. My current 40152 pack sits at 40.2V after charging and doesn't drop further. What...
  11. battman

    Barron Greig's Homebrew MAX11081 Based BMS

    Hi Folks, Since there can never be too many different BMS implementations, I'd like to add a MAX11081 based one to the pile! At the time of writing, Googling for MAX11081 doesn't turn up much other than spec sheets, short news articles and a couple of short references of Endless Sphere, so...
  12. battman

    jonescg's NEW electric racebike BUILD thread!

    Could you provide links to some suitable sources in Australia for these? Is there anywhere local that has some of the items you need to avoid shipping costs? That said, I'm probably more at the braided line level of contribution than the complete front wheel end of things! How do we avoid...
  13. battman

    jonescg's NEW electric racebike BUILD thread!

    Would you entertain the idea of receiving a (modest) financial contribution towards this project? I really want to see it happen. I'm not going to be putting together something fantastic like this myself as much as I would like to. So the next best thing I can do is live vicariously through your...
  14. battman

    PCM material for DIY pack builders ... where to get?

    Kool-aid drinker here :wink: ... This summer the ambient temperature will reach 110F and possibly more here in Phoenix. Under these weather conditions my pack could get warm enough to potentially degrade the cells. I am looking at experimenting with wrapping my pack in PCM material (maybe a...
  15. battman

    A123 20Ah O.K for winter use.

    You will likely see reduced cycle life, reduced capacity and increased IR below 10C. I never charged as low as 0C, probably 3-4C and, if my A123's are representative, it's just not worth charging them in those conditions for the hit the cells take.
  16. battman

    A123 20Ah O.K for winter use.

    Yep, that's pretty much what I do these days. I just ride my motorcycle into the living room and consider it an ornament at that point. The pack also gets kept cool in summer by the house A/C then. You definitely need to be able to trust your batteries, BMS and wiring skills to leave such a...
  17. battman

    A123 20Ah O.K for winter use.

    The A123 spec sheet does not indicate charging temperature range. From personal experience of using these cells (*) in my motorcycle project I found that charging these cells in low temperatures (between 0C and 10C) has a very bad impact on their internal resistance and capacity. From...
  18. battman

    E-max 110s lifepo4 upgrade

    If the problem is the pulse duration being too short, rather than the frequency of pulses being too high, then this might be addressed by positioning the magnet and sensor closer to the center of the hub so that the velocity at which the magnet moves past the sensor is lower.
  19. battman

    A123 20Ah Quebec Group buy(Canada) cells ARRIVED 24.57$/cell

    My question was about charging, not discharging. The tests you are referring to may be done at 25 celsius ambient but what is the MINIMUM recommended charging temperature in the A123 documentation you have? Is it 10 celsius like the Battery University website? Is it 25 celsius? Can you just post...
  20. battman

    A123 20Ah Quebec Group buy(Canada) cells ARRIVED 24.57$/cell

    Thanks. That is generic advice for lithium but you mentioned earlier the A123 documentation indicates a charging temperature "close to ambient". Is "close to ambient" 10°C? The A123 documentation you have that covers charging temperature - if you have it in electronic form could you post it here...
  21. battman

    A123 20Ah Quebec Group buy(Canada) cells ARRIVED 24.57$/cell

    Thanks, I understand the concept of reading documentation correctly. The only documentation available to me was the attached spec sheet which does not mention charging conditions. If you can post a link to the additional documentation you have that describes the recommended charging temperature...
  22. battman

    A123 20Ah Quebec Group buy(Canada) cells ARRIVED 24.57$/cell

    This may tie in with Doctor Bass's comment about them not liking being at full SOC for much time - be wary charging these in cold temperatures! I have a 3P24S pack of these in a motorcycle in Arizona. I noticed a significant irreversible capacity loss (10%+) and increase in IR after fully...
  23. battman

    Agni motor tuning and racing

    Hi Folks, Earlier in this thread I raised an issue I was having with excessive brush wear. I sent the motor to Steve Labib (Jozzer) for analysis with the following results: Steve verified that I had not abused the motor with excessive current and noted the following anomolies: low resistance...
  24. battman

    Agni motor tuning and racing

    Agni told me that 90C was the maximum allowable temperature measured at brushholder and I've noticed that after stopping bike temperature continues to rise a bit as heat continues to be released from motor core.
  25. battman

    SonyTo Enter EV Battery Market 2015-Replacing A123 in Tools?

    Look at the text directly above the cycle life graph, it says "1000 cycles to 80% nominal capacity" for 1C charge/ discharge at 100% DOD. So there appears to be inconsistency in their data sheet.
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