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  1. jdh2550

    New 16-cell Battery Management System (BMS)

    For us lazy and/or soldering iron challenged folks :) when do you think you'll begin offering assembled systems for use with other battery packs? (If I read the thread right you're going to wait until you go to surface mount before offering the assembled systems)? The board looks great and...
  2. jdh2550

    So what did Tesla drive? (1930)

    Drunkskunk - Thanks for the Tesla lesson. Well written and good insight. I really enjoyed reading this and learned a bit more about the infamous converted Pierce Arrow.
  3. jdh2550

    So what did Tesla drive? (1930)

    This is another place to start (not saying it's the only source one should trust - just a starting place): http://en.wikipedia.org/wiki/Tesla_electric_car
  4. jdh2550

    BMS package for A123 cells

    Err, :? , your post mostly confuses me. Are you saying it's easy to solder? That might be the case for you, but not I. Second up, your talk about $500 for artwork doesn't seem to jive with the fact that Jeff can get boards for $2 a pop now. Isn't the artwork required for producing the board...
  5. jdh2550

    So what did Tesla drive? (1930)

    Yep, reports of Tesla driving such a car have been pretty much proved to be BS (that's not a historically correct term - but you get the idea). I think there's a discussion of the lack of validity of the claim on wikipedia - but I was too bone idle to look it up.
  6. jdh2550

    BMS package for A123 cells

    I presume that's the price for the unpopulated board? How much for a populated "turn-key" solution? (I can't solder surface mount components for sh!t). Thanks.
  7. jdh2550

    Looking for feedback - IZIP and CurrieTech owners & deal

    Of course, I have to disagree with this ;-) Motor scooter sized EVs are practical today. While the batteries supplied are marginal that's usually because of cost considerations rather than battery capability. A good set of U1 sized SLA's with battery balancers will give a scooter a...
  8. jdh2550

    Custom A123's almost here!

    My XM-2000, the controller has a cut off at 50A and is a 60V system = 3kW. The newer Z-20 has a claimed 90A cut off so that will be up to 4.5kW.
  9. jdh2550

    .

    I believe GM have a deal with A123 for batteries for the Volt. I expect them to bring it to market - as it seems that they need to fill a hole in their marketing strategy. They certainly aren't doing it because they give a damn about the environment or anything else. If BEVs are to make...
  10. jdh2550

    Scientists Invent 30 Year Continuous Power Laptop Battery

    Sounds like high current draw is an issue - so not much use for EVs: BetBatt, Inc is the licensee of this technology.
  11. jdh2550

    Custom A123's almost here!

    Can anyone point me at a discharge curve for 50A (approx 20C)? I looked through rmitchell's RC forum references but the max I found was a 30A (about 13C). Thanks.
  12. jdh2550

    Battery chargers

    Good question: As far as I know the important aspects of the charging cycle are: 1) Voltage profile required by the chemistry (x amount of time at y voltage for chemistry z) 2) Internal resistance of battery pack - which determines the maximum safe charging current for a given chemistry (heat...
  13. jdh2550

    The politics of NiMH

    Wow, things certainly took off like a rocket around here. Some observations: Although the "boffin" (William Tahil) quoted by safe has an impressive title he's not very current with Lithium (anyone who still quotes "the attendant safety issues of Lithium" isn't talking about the LiFePO4...
  14. jdh2550

    The politics of NiMH

    Toorbough ULL-Zeveigh - WOW! Thanks for your detailed post. I learned much about both NiMH and the Chevron/ECD Ovonics relationship. Some questions for you: (1) Where's a good source for me to read up on more of what you've written about? (I thought I was fairly well up to speed on it - but I...
  15. jdh2550

    Custom A123's almost here!

    To clarify my quote - I mean with regards to Peukert effect. Whereas So, OneEye, you're saying that my assumption is incorrect? I.e. adding packs in parallel reduces the effective discharge rate, which in turn negates the high draw issues? I thought that basically in a parallel circuit the...
  16. jdh2550

    The politics of NiMH

    Hey, now I said the agreement was sealed didn't I? ;-) BTW, Do you know the specs of the highest Ah pack you can buy "off the shelf"? I might after all be full of sh*t... (I don't think I am!) YES, DO IT NOW!!!! I'll invest (does $5 help you out?) Of course you'll be competing against A123...
  17. jdh2550

    Custom A123's almost here!

    But how long do you draw 55Amps? I draw 48amps while cruising at 42mph (WOT) on a flat road. Given that about 5 miles out of my 12 mile commute has either a 45mph or 50mph speed limit I am drawing that amperage for around 10 minutes. For the rest of the ride I pull up to 48A when accelerating...
  18. jdh2550

    The politics of NiMH

    No you can't. You can make larger batteries out of a collection of small cells. But that's not the same as making a larger cell. Those smaller cells combined as one battery will most likely not perform as well as a single larger cell. It's all to do with the Peukert effect - see that other...
  19. jdh2550

    Custom A123's almost here!

    mcharles13 - you say you're an A123 vendor - do you have access to a technical resource there? Ask them what the Peukert constant is for the cells you use. doctorbass - what max amperage are you drawing? My point is that it might not be a big effect in your scenario but it might be a big...
  20. jdh2550

    Custom A123's almost here!

    I haven't read all your post yet - but this statement is dead wrong. I suppose you're gonna make me work for the right to say that, eh? ;-) Read the wikipedia entry and you'll see that Peukert constants for lithium batteries are smaller (see example 2). But they do exist. Also bear in mind...
  21. jdh2550

    Custom A123's almost here!

    If people are interested in continuing the discussion of the politics of NiMH which CGameProgrammer and usatracy both alluded to - I've started another thread (because this topic REALLY interests me): http://endless-sphere.com/forums/viewtopic.php?t=2342
  22. jdh2550

    The politics of NiMH

    On another thread a side discussion of NiMH arose. Rather than take that thread further "off into the weeds" I figured I'd bring it over here. Hopefully others will want to discuss this further. First to speak to the NiMH vs. LiFe debate as far as EV usage. Here's my understanding: LiFe is...
  23. jdh2550

    Custom A123's almost here!

    mcharles13 - the effective capacity of a battery changes dependent on the rate you discharge it. So, by just stating 2.3 Ah is incomplete. Because (even with Lithiums) if I draw 2.3 amps it will be at zero before 60 minutes have elapsed (unless it's the 1 hour rate that has been quoted)...
  24. jdh2550

    Custom A123's almost here!

    My only intent for a different voltage would be to allow for slightly more headroom to cover the sag. I wouldn't want to run the motor at a higher voltage (well, actually I guess i'd be tempted to!) Stop picking on me! Wah, wah! :cry: if I want to ask half-assed questions that show I'm dumb...
  25. jdh2550

    Custom A123's almost here!

    Now there's an invitation! :o However, the short answer is I'm simply exploring possibilities. I see that I was naive in assuming 20 cells because I didn't consider voltage drop at 50A (the max I've seen is 48A). As far as triggering the controllers over voltage cutout - I wonder if that's...
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