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  1. #51
    Senior Member
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    All li ion cells die someday.

    I have some A123m1 cells recycled from 2006 Dewalt packs that are still going strong and might out live me.

    Li ion cells get little shorts in them over time.

    Enough of these little shorts will kill off the cell.

    Quality name brand li ion cells are designed to die in a non fantastic way, not short out quickly when they die.

    Cells designed to die in a non fantastic way are the only cells that should be used with a bms.

    All rc lipo battery makers say to always charge rc lipo with chargers made for rc lipo batteries and to always attend the rc lipo batteries being charged.

    Rc lipo can get large shorts inside the cell and cause the cell to die in a fantastic way.

    A bms is designed to kill a pack if needed but the way they kill a pack was not designed for killing rc lipo cells that were not designed to die in a non fantastic way.

    Rc lipo was designed for rc racing and max power, lowest weight.

    Rc lipo was not designed to last very long or die in a non fantastic way.

    Good for ebike racers that have money to burn I guess.
    Last edited by biker; 01-04-14 at 07:33 AM.

  2. #52
    Senior Member DrkAngel's Avatar
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    Lightbulb

    Interesting, I have noticed ...

    In many years and with many many builds, 18650 laptop cells seem extremely ... reliable-consistent.
    In series they never seem to fail ... they just fade away.
    Of course, I, typically, build packs using same brand-rating cells.
    But it is amazing how evenly and predicatively cells head towards "end of life usable."
    An initial bank capacity equal build usually retains acceptable high and low "equalization" for many many cycles (100's?).
    Even when cells in same bank vary in capacity!

    Of course you must avoid overly low or high, (damaging), discharges-charges!
    Last edited by DrkAngel; 01-05-14 at 12:45 PM.
    "Best of all! ... I get to play. ... http://www.bikeforums.net/attachment...&thumb=1&stc=1
    Sorry! ... I'm addicted to improving enhancing.
    With side orders of inspiring enlightening!"

    Acronyms

  3. #53
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    Using good name brand high quality li ion cells to build an ebike battery is nice.

    Not everyone lives near a big city where laptop packs are plentiful like I do though.

    Buying the packs on eBay is very hit or miss. Found that out.

    I like to ebike way out in the woods, far away from where a car could save me if I broke down.

    So for travels way out in the woods I need a setup that is very reliable.

    Quiet ebike sneaks up on wildlife so I can take pictures.

    And a setup that won't catch the woods on fire.

    Currie brushed motor with a small A123 power pack backed up with a laptop pack will go all day.

    We live in South Florida and test this stuff out all year, on road and off road, almost every day, on an ebike or etrike.
    Last edited by biker; 01-16-14 at 10:40 AM.

  4. #54
    Senior Member DrkAngel's Avatar
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    Lightbulb 33.3V 31.2Ah eZip RMB Pack Build

    Well, I keep claiming that I have squeezed the maximum number of 18650s into the oem eZip pack.
    7s12p .. 8s12p ...
    Finally ... this might be true.

    Next build was going to be a "hybrid" 18650 & flat Lipo project ...
    but I got tired of all the old Sanyo 18650s laying around.
    So I gathered them all up and selected all that measured a retained voltage higher than 4.10V.
    (After being equally charged to 4.20V+ 8+ month ago)

    9s12p (33.3V 31.2Ah) eZip Rebuild = 1kWh!!!
    By staggering the cells I am able to fit the cells in 9 wide.
    Case will stack 12 1/2 cells high if I remove center screw and use only a 3/16" Masonite bottom support-protection "shelf".
    I chose the 90 best retained voltage cells and stacked so as to have "equal" capacity per stack.
    Now, 9 x 12 is more than 90 cells ... and sorting solely by retained voltage is a poor measure of capacity! ... ?
    But ...

    Bulk Building
    I rated and sorted "build" cells solely by "bleed down" - "retained voltage", and will assemble and test as a 9s10p pack.
    After initial discharge-recharge cycles, I will "equalize" pack using precisely capacity rated Sanyo cells pulled from my last batch of recycled Lenovo packs.
    By adding them as the final 9s2p.
    Pack will be used on my Snow Beast and as a testbed for a future build using "new" (NOS) cells.
    I have 2 eZips that run nicely on 33.3V batteries.
    These Sanyo cells are 3.6V and after learning my lesson by damaging with 4.20V charging, I will be charging at 4.0-4.05V, for increased life.


    I will add 1/2 cell height (9mm) "blanks" as additional support for the alternate "banks".



    Leftovers?
    Well ... this leaves a couple hundred "lesser" condition-capacity old Sanyo 18650 cells laying around.
    Leftovers and re-recycled from 6 years of multiple builds.

    So, a "true" bulk build!
    I have a couple "antique" 200w inverter packs.
    2 - 18Ah SLA outputting 200w continuous through a GFCI 110V AC outlet.
    Well I'll pull the 12V 36Ah Lead Acid and pile in all the 18650 cells that will fit.
    3s66p might fit = 171Ah
    (Check bank voltages after 1st discharge, add cells to any low bank - re-cycle - repeat.)
    But, probably be lucky to get 72Ah actual capacity out of these ... rejects.
    Still, that is 200% the oem capacity at 1/2 the weight.
    Most importantly!
    I have those old cells safely stored and not laying around.
    And, of course, a nice supply of emergency-portable power.
    It also has a 12V "cigarette lighter" outlet for a more powerful inverter or 12V.


    Will add pictures ...
    "Best of all! ... I get to play. ... http://www.bikeforums.net/attachment...&thumb=1&stc=1
    Sorry! ... I'm addicted to improving enhancing.
    With side orders of inspiring enlightening!"

    Acronyms

  5. #55
    Senior Member DrkAngel's Avatar
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    Gitten-er-done!

    After draining my 33.3V 26Ah (9s10p) to 33.2V, ~3.7V per bank, I marked resultant voltages and added complementary 2s to each bank as deemed advisable.
    Lowest bank got the best cells - best got the worst.
    Lowest bank (3.65V) got 4500mAh, highest (3.71V) got 4100mAh, the remainder apportioned in between.
    Since I will discharge to not below 3.8V, where cells were within 2/100th of each other and "good" ... now they are just "more good".

    At 3.8V - 4.05V capacity is still >20Ah ...
    I will measure Ah capacity after next deep discharge ... though I typically recharge immediately after any use and weather is too cold for any extended rides, so, full capacity test might wait till near Spring.



    Last 2 banks were pulled from a different batch that had oddball tabs ... sorry, wanted it to look prettier!

    I will monitor 1st few discharges ... mainly to check for bad-poor solder connections.
    After that I will rely on bulk charging with the occasional balance check.

    Edit - I did add 4 - 9mm, 1/2 cell height, blanks as support for the alternate banks.
    And re-covered all cells with a wrap of boxing tape.
    Both ends of cells were covered with closed cell polystyrene, (foam sheet, as is used for durable padding), to secure-stabilize cells tightly in pack.
    "Best of all! ... I get to play. ... http://www.bikeforums.net/attachment...&thumb=1&stc=1
    Sorry! ... I'm addicted to improving enhancing.
    With side orders of inspiring enlightening!"

    Acronyms

  6. #56
    Senior Member DrkAngel's Avatar
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    Lightbulb 22.2V 30.24Ah Battery Build

    Quote Originally Posted by DrkAngel
    I believe I will attempt to build another 22.2V pack.
    Previous 22.2V pack consisted of 40Ah+ of old re-re-recycled Sanyo cells and I rated as ... lack-luster - too wimpy! in performance.

    Proposed build will consist of the same type Lipo cells used in 25.9v 22mph pack.
    Instead of using the 12 side cells as an additional 7th bank they will add 2 cells to each of the 6s "bricks".
    Same total capacity
    7s12p = 25.9V 25.92Ah = .671 kWh
    will become
    6s14p = 22.2V 30.24Ah = .671 kWh
    22.2V pack should be an enforced economical and "legal" alternative for my 2008 Trailz w/16T mod and my 2013 Trailz LS w/13T mod.

    22.2V Lipo should outperform, or at least compare favorably with, 24V SLA.
    SLA 24V controller w/~21V LVC should be perfect for the 22.2V Lipo.
    Balance charge with cheap iMax B6 or equivalent ~$20
    6A CC/CV charging with MeanWell S-150-24 ~$20 + shipping
    And should provide 600% the range of the oem SLAbatts! ... at 1/2 the weight!!!

    Oh ... and ...
    5x the range of the $400 Currie Lithium alternative (6.14Ah)
    3x the range of the $600 Currie Lithium alternative (9.6Ah)
    22.2V 30.24Ah NOS Laptop Lipo ... ""100701" = 2010 July 01 dated cells.
    I know, I know ... I said 22.2V was too wimpy!

    But, I tried my latest 25.9V 25.92Ah battery build on my latest ...
    2013 eZip Trailz LS w/13T motor sprocket ... cruised at 22-23mph.
    Couple problems:
    Exceeds "legal" - 20mph.
    Running at +22mph strains the battery well past my recommended .5C.

    Running the numbers ... 22.2V looks to cure both problems.
    Took the 7th"s" and split it up between the remaining 6s.
    Dropped top cruising requirement by 100w.

    1st build using the newer black eZip "RMB" pack.
    I had to chisel "ribs" out of pack, to provide proper clearance.
    Used Formica as shelves to support cells.
    Wedged a wooden block as additional support under lower cells-Formica.



    I did add a balance connector ... had the silicone 22ga balance connector anyhow ...
    Just cause I could ... I balanced all banks to precisely 4.186V.
    Ooh! Tried bleeding down a bank using jumper wires connected to ends of soldering *** tip. Worked pretty good ...



    Speed settled perfectly ... just a fraction under 20mph.

    Testing now.
    Ran 20 miles at 19mph+ and have all banks still at 3.84V.
    Likely another 7-8 miles at 19mph?
    Oh ... motor only, no pedal assist.
    40miles plus @ 16mph?



    Will mod a MeanWell S-150-24 as 25V 6A charger.
    The 24V 40mm fans seem a bit fast-loud so I tested with a 2watt 47ohm resister, in series, and resulted in a moderately quit fan with minimal resister heat.
    Upgraded charging wire to 14ga for rapid charging ... if I care to try ...

    Reread the post...
    Sounds like I rebuilt my 25.9V into a 22.2V.
    Separate build!
    I still have both and need 25.9V for my 16T mod eZips.
    "Best of all! ... I get to play. ... http://www.bikeforums.net/attachment...&thumb=1&stc=1
    Sorry! ... I'm addicted to improving enhancing.
    With side orders of inspiring enlightening!"

    Acronyms

  7. #57
    Senior Member DrkAngel's Avatar
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    Cool 22.2V 6s LiPo Bulk Charger (24.84V 6A)

    Built 24.84V 6A MeanWell charger (S-150-24) ... for 22.2V LiPo pack.
    Yes I labeled it.
    Don't want to plug into wrong pack!
    18ga computer power cord fit through wire hole.

    4.14V per bank looks optimal.


    MeanWell will be outputting 6A continuously for nearly 5 hours so I felt it advisable to add a 24V fan.
    At about 25V it seemed annoyingly loud , so ... I added a 47ohm 2w resistor in series.
    Dropped voltage at fan to 21V and quieted to ... acceptable.
    Fan placement appears optimal.
    Last edited by DrkAngel; 07-22-14 at 07:45 AM.
    "Best of all! ... I get to play. ... http://www.bikeforums.net/attachment...&thumb=1&stc=1
    Sorry! ... I'm addicted to improving enhancing.
    With side orders of inspiring enlightening!"

    Acronyms

  8. #58
    Senior Member DrkAngel's Avatar
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    Cool 25.9V 25.92Ah eZip LiPo Build + Rebuild

    Quote Originally Posted by DrkAngel
    Built a replacement 25.9V 25.92Ah Recycled Lipo pack for my eZip.
    7s12p 2160mAh cells, paired, in 3s2p 6 packs.
    All new packs-cells, with identical date of manufacturer.
    (081209 2008 December 09 ... Yes! ... 5 years old+.)
    Charged in 4 bay bulk chargers last summer ... all cells were still 4.09 or 4.08V.
    Assembled and ran for 20 miles at between 18 and 22mph.

    Resultant cell voltages were either 3.82V or 3.81V ... except the 12cell side cells at 3.80V,
    Close inspection found a poor solder joint
    Fixed ... and charging now.
    Will balance at full charge -4.17V per cell as maximum, typical "full" charge will be ~4.05V ... except for trips.
    I anticipate many years and many many thousands of miles.

    These 6 packs are ideal for 22.2V, 33.3V, 44.4V builds.
    7s is awkward ... but does fit efficiently in the eZip RMB packs.

    After initial monitored cycles, I intend on bulk charging only ...
    No BMS! ... I view them as band-aids for defective packs.
    (Of course I also prefer the tech friendly Windows XP ... so ...)

    Additional points:
    Removed built in pack fuse, to simplify wiring.
    Added in line fuse (40A)
    Replaced all internal ≥ 12ga
    Except charging wires upgraded with 16ga
    Layed sheets of closed cell foam below and above, to stabilize cells in pack.
    "Bricks" of cells are supported by "sheets" of Formica.

    Old one passed its 3rd year and 7000 miles ... and was built with the rejects, the recycled packs that would not charge properly!
    Still 10-12Ah usable ...
    Will keep until I need the shell for next build.
    Quote Originally Posted by DrkAngel
    Tragedy
    Broke a LiPo ribbon cable - thin aluminum
    One bank low, so I disassembled and traced the problem.
    6pack, nearest the back-bottom, broke the pos power ribbon from one cell.
    For convenience, I have the top banks setting on the connections.
    I better supported the top bank by placing wooden spacers between the bottom banks and the Formica "shelf".
    If it does not work for an extended period, I will ...
    I will flip upper bank and run longer wiring. (Probably a good idea!)


    Ribbon broke at poorly supported bank with brown heatshrink.

    650+ miles
    4th metered recharge 3.70V - 4.182V = 24.42Ah (Black iMax B8)

    1st metered recharge 3.82V to 4.16V = 18Ah.(Blue iMax B8)
    2nd metered recharge 3.695V - 4.170V = 24.264Ah (Blue iMax B8)
    3nd metered recharge 3.666V - 4.185V = 27.647Ah (Black iMax B8)
    4th metered recharge 3.70V - 4.182V = 24.42Ah (Black iMax B8)
    Sadly my "repair" with added support etc. failed miserably!
    2 banks showing additional damage, after a few cycles.
    So, rather than another "repair" I pulled the 6 major banks and replaced with new 2010 cells.
    Yes!
    I did position to prevent further damage!



    I have run a few cycles and then a deep discharge for capacity check.
    Discharged to 25.66V.
    All cells were equal within 2/1000th V at 3.666V!
    This shows excellent matched capacity!
    Beyond any reasonable expectation.
    The quality control and durability built into these 4 year old cells is astounding!!!

    Did a metered recharge using iMax B8 (Blue).
    3.666 - 4.156V = 25.376Ah

    #1 Laptop LiPo Build
    2011 - 24.0Ah (25.9 to 29.4V)
    2012 - 20.8Ah (25.9 to 29.4V)
    2013 - 15.8Ah (25.9 to 28.7V) 6500+ miles
    2014 - 13Ah+ (25.9V to 29.2) 7000+ miles

    #2 Laptop LiPo Build
    1st metered recharge 3.82V to 4.16V = 18Ah.(Blue iMax B8)
    2nd metered recharge 3.695V - 4.170V = 24.264Ah (Blue iMax B8)
    3nd metered recharge 3.666V - 4.185V = 27.647Ah (Black iMax B8)
    4th metered recharge 3.70V - 4.182V = 24.42Ah (Black iMax B8)

    #3 Laptop LiPo Build - Rebuilt 25.9V 25.92Ah 2010 Laptop LiPo (Dell)
    1st metered recharge 3.666V to 4.156V = 25.376Ah.(Blue iMax B8)
    Last edited by DrkAngel; 07-24-14 at 08:27 AM.
    "Best of all! ... I get to play. ... http://www.bikeforums.net/attachment...&thumb=1&stc=1
    Sorry! ... I'm addicted to improving enhancing.
    With side orders of inspiring enlightening!"

    Acronyms

  9. #59
    Ride more, eat less cat0020's Avatar
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    New to ebike, just ordered a 48V 1000w 26" rear wheel to use on my old hardtail MTB.



    Can i can some suggestion where to souce RC or laptop LiPo batteries?

    I plan to commute between Manhattan, Brooklyn and Queens, distance between chrarge will likely be under 20-25 miles.
    Last edited by cat0020; 08-13-14 at 05:04 AM.
    Master your environment, and you will survive just fine.
    Chances favor the prepared mind.

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