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    My 2nd Fuse link 18650 battery build

    Nice job on that build - so it looks like each cell is fused but only on the positive terminal is that correct. Or is the fusing just on the parallel connections not the series - schematic if you have the time Much appreciated Dennis
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    Ultracapacitors: how to?

    Ive tried some of the RMS formulas....simplest worked great....Activated carbon....fish tank filter material run through coffee grinder to a fine powder...sprinkled onto aluminum foil tape strip for each electrode...concentrated salt water solution into soaked paper towel for membrane....ran...
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    Ultracapacitors: how to?

    For a lot of how to and learning experience on ultra caps watch the youtube videos by Robert Murray Smith. He shows you how to make your own supercaps. A few months ago he demonstrated a supercap powering his electric scooter. I think you'll find it under EESD. I've duplicated some of his...
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    Connection order Bestech PCM/BMS

    Peter and others, I received this answer as well from Ada Li at Bestech. I'm waiting for a further explanation - maybe you can help. I cannot find B32 on my BMS so very confusing in step 4. Is there any BMS connection to B+ for power? other than the 10 individual cell connections? "1)Connect...
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    Connection order Bestech PCM/BMS

    thank you Peter much appreciated
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    Connection order Bestech PCM/BMS

    Hello - I have a Bestech Power HCX-132D PCM/BMS . 10S5P Li pack. Is there a right/wrong or best way to make the ORDER of connection. i.e. Connector with 10 cell voltage sampling wires, then either P- or C- or B+ or P-, C- B+ then connector with 10 cell voltage sampling wires ???
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    Connection order Bestech PCM/BMS

    Hello - I have a Bestech Power HCX-132D PCM/BMS . 10S5P Li pack. Is there a right/wrong or best way to make the ORDER of connection. i.e. Connector with 10 cell voltage sampling wires, then either P- or C- or B+ or P-, C- B+ then connector with 10 cell voltage sampling wires ???
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    JP spot-welder, FET-switched, timed adj. pulse

    Same thing with me..........the FETs weaken with every weld it seems and then they go. If one goes bad and you replace it you still have weak sisters that msu not share the load and they go...Others have said here...replace them all when they go bad. Other subtle factors are strength of...
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    JP spot-welder, FET-switched, timed adj. pulse

    Practice with some sample nickel ribbon and scrap cells first....
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    JP spot-welder, FET-switched, timed adj. pulse

    Thank you for finfing that reference. Biggest problem nw is weld spot form the probe attached to Battery+ is several times larger deeper than the one next to it....sometimes burning through. Probes have been cleaned and sized to same tip diameter??????
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    JP spot-welder, FET-switched, timed adj. pulse

    I've been reading and enjoying everyone's posts - lots of experience to share here - so I thought I'd throw mine out there as well. I have the same 6 FETs driven by 1407 driver like most designs here. Been blowing a few FETS now and then and even a couple of the driver chips shorted the...
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    JP spot-welder, FET-switched, timed adj. pulse

    On my layout I have 6 82 ohm resistets fanned out from the 1407 driver chip.....large ground planes and alum bus bars used for source and and drain on double sided pcb......weak link is source connections on fet....I try to fatten it with solder and larger pad to ground plane
  13. G

    What to substitue for Samsung 35E

    Thanks - I'll see if I can find those of 3500mahr or greater - without going to the 3.7V cells
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    What to substitue for Samsung 35E

    Hello I have to replace a few Samsung 35E 18650 cells in a pack. The substitutes will only be paralleled with themselves - not mixed in a parallel string with the 35Es. I looked on ebay to buy a few replacements and need some help to sort things out. I know I need a 3.6V cell and can find...
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    Replacement 18650 sleeves???

    The white insulators where salvage from old cells...not sure where to buy new
  16. G

    Replacement 18650 sleeves???

    Ill check out Hobby King and local RS thanks. Too much thickness may be an issue since I have a close packed array. Thanks
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    Replacement 18650 sleeves???

    Oh - found some at Fasttech but so far no domestic US supply s
  18. G

    Replacement 18650 sleeves???

    I damaged some perfectly good 18650 cells - about 10 pieces. They're brand new so worth saving, if I can resleeve them. Any ideas where to get the very thin shrink wrap or ? just try some sort of tape. I have the white positive end plastic washers which I will reuse. Thanks anyone
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    Lithium Batteries Shipping Rules Discussions

    Opportunity here for someone in US to take a boat load of cells and redistribute ???
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    Lithium Batteries Shipping Rules Discussions

    Just tried to order 16 18650 cells from Fastech (Sanyo 3500mahr 3.6V) - when finalizing order, NO, shipping options were available - they were all grayed out. I sent a note to them asking what my options are. Not a lot of hope here to ship batteries from them to US. Side question - what US...
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    supplier for Samsung 35E ?

    Ill track tumich down in the New Sales secion. Thanks. I am in the US (Michigan) so the slow boat from Europe for cells is a bit painful.
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    supplier for Samsung 35E ?

    Hello - few month back received great lot of Samsung 35E cells from tumich. Now I need a few more - short of randomly ordering from ebay - can anyone suggest a good supplier. I don't see tumich on the board these days. or What's my next best choice - I will be mixing them in a pack (5P 10S)...
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    JP spot-welder, FET-switched, timed adj. pulse

    Hi....its a home brew but very similar to J P with 1407 driver chip and 6 parallel 1324 fets. Twice blew F E T closest to driver. All pins shorted and drain lead fused. Need to replace all six I guess and add external avalanche diode. Trying to understand root cause of failure...avalanche...
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    JP spot-welder, FET-switched, timed adj. pulse

    Heres a question for the engineers in the group. How can I determine the root cause of my FET failures. FETs blow either because of too much forward current during the weld time, or two much reverse current (avalanche) at pulse turn off. So from what I've read here you can: Lower the forward...
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    4P10S Pack - w/o Welded Tabs

    Thanks for the reply - double sided board used to help distribute the load - if you use 2 oz. copper then single sided should be OK. But I'm pull about 20 amps and I needed the extra conductivity. Only had 1 oz stock on hand :( I like the steel threaded rod better since nylon tends to 'cold...
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