BT40s + SolarStorm case with 4 Samsung cells, 30 mins runtime....?- Mtbr.com
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  1. #1
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    BT40s + SolarStorm case with 4 Samsung cells, 30 mins runtime....?

    Hiya
    As title suggests im getting less than 30 mins runtime from a BT40s with fully charged Samsung icr18650-26Fs. Obviously it has to be the cells underperforming, could anyone recommend which 18650s would be better? Or maybe Id be better off just getting a pre built 4 cell unit?
    Any thoughts appreciated...
    Thanks!

  2. #2
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    Quote Originally Posted by midnight_rambler View Post
    Hiya
    As title suggests im getting less than 30 mins runtime from a BT40s with fully charged Samsung icr18650-26Fs. Obviously it has to be the cells underperforming, could anyone recommend which 18650s would be better? Or maybe Id be better off just getting a pre built 4 cell unit?
    Any thoughts appreciated...
    Thanks!
    I would recommend getting a battery from mtbrevolution. Hunk Lee on ebay has some nice packs as well.

  3. #3
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    are you balance charging your cells???

    Also what is showing the low run time, the case or the light?

    Is it the light is shutting off when it gets low or shows red light after 30mins?

    How long did the cells sit fully charged in the case before use?

    The case works but it isnt all that great. The on board protection circuit is almost useless, the wires for the connector are really thin.

    Ive had good luck with the case but I eliminated the USB and fixed the protection issue. but I also pull my cells out to balance ever few uses.

  4. #4
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    MR, Samsung 26F are just nice cells, one of the best price/performance. There might be some other issues or you have got fake cells. Once I've came across fake ones so please take detailed pictures and post them here. Also see how the wrappings are made, are there any bubbles, darker spots/flecks, what is printing on them, etc.

    Next measure the voltage of each cell after the charging. Use Digital multimeter.

    3rd thing might relay in the case, but first wee need to know everything about cells you have.

    4. The wires might be to thin to support BT40 on high. You didn't explain on what mode you are getting 30min runtime and can you run it more on lower modes. What status led color are you getting. What is the cells voltage after 30min runtime ????
    You gave us to few details....

  5. #5
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    Many thanks guys, i'll do some more tests today and get back to you with more details. Ledoman, the cells were taken from a laptop battery, cant recall exactly which one, possibly a Leveno so I guess we can eliminate fake cells from possible culprits...?
    Thanks

  6. #6
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    If laptop battery was genuine, the cells are most likely not fake. But if that battery was used before, you might be getting "worn" cells with degraded capacity. BTW, Samsung 26F isn't the best among other models, as its service life is shorter. If you don't have any equipment to perform measurements of cell's state, you can at least check each of them separately using single-cell torch & watching the runtime...

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    Thanks, here's where I am at the moment:
    4 cells charged to 4.21, 4.19, 4.20 and 4.18.
    BT40s set to high, indicator light went from green to blue to red within 2 minutes.
    Stayed on red for 15 minutes, and its been flashing red for just over an hour now.
    One flashing green light on SS case, output of lamp seems on the low side.
    Doesnt sound great does it?

  8. #8
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    Ok that explains everything. You are using wornt out cells. You better be getting different ones.
    You should be saying you are using cells from laptop pack at first place!!! You might missleading users Samsung 26F cells are bad. They are not. Shurely not the best, but good enough for most lights we are using.

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    Thanks very much Ledoman. Yes I should have made it clear they were harvested from laptop batteries. I really am clueless about batteries and i just assumed if it charges, and holds its charge then its not worn out...
    I have a few $ credit at GB, would you prefer one of these over the other?
    Panasonic NCR18650B
    NCR18650B 3.7V 3400mAh 18650 Rechargeable Li - ion Battery ( 4 Pcs )-15.37 and Free Shipping| GearBest.com OR
    Samsung ICR18650 - 32A
    4 PCS of 3.7V 3200mAh 18650 Rechargeable Li - ion Battery with Protection Board ( ICR18650 - 32A )-17.34 and Free Shipping| GearBest.com
    Or would you recommend something else from GBs stock?
    Thanks again!

  10. #10
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    Anything from known brand (Panasonic, Sanyo, LG, Samsung, Sony) would be good enough for most of your needs. If you need more power then I would look for higher current (cells that can deliver higher currens).
    The new Samsung 2600 are still good enough. They can deliver full capacity up to 3A each. I've ploted their discarge curve and they are fine. Of course there is plenty other cells too. It is just how much runtime you want and how much do you want to spend.
    You can try to look Henrik's comparator to help you with decissions: Battery test-review 18650 comparator

    On the other hand $15.37 is very good price for Panasonic NCR18650B 3.7V 3400mAh. Some time ago you would get only two cells for this much money.

  11. #11
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    Great, many thanks. Just a few more things, would you recommend protected cells? I ask because i dont really trust the box as a stand alone charger, i read on the thread about the box that it is very poor at balancing which i guess means that unprotected cells might get overcharged...? Also, I tried to find out how to calculate how many amps a cell delivers but its still clear as mud. The only data for any given cell is the mAh and voltage, how do i get to the amps?
    Apologies again, as i said i really struggle with electronics...
    Many thanks!

  12. #12
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    The case isn't the cause of balancing, some just happen to have a bad connection on one side or the other so it discharges and charges 1 pair more than the other. Its never a good idea to use loose cells in cases like this without a proper knowledge of balancing them. Not much to it but you'll trash cells, protected or not (protected will just last longer, but it still allows deep discharge). Truely its far better if your going to play with loose cells to have a proper charger. You cam use the case to charge them for a few uses at a time between balancing and charging on proper charger.

  13. #13
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    Well, sounds bit complicated, but balancing can be very simple. You can charge cells in the case with tipical 8.4V Li-Ion charger and from time to time take them out to balance. Balancing is simply done by connecting all cells in paralell when voltage differences are rather small max. 0.1-0.2V or so. This should be the case with new quality cells anyway.

    You can make your own balancing gadget by using 4 cell holder like THIS. You simply connect all bays on each side and voila you have balancing gadget. Simply as that. Of course don't mix orientation of the cells. There going to be a lot of smoke... at best.

    Of course the safer way (for dummies ) is using 4 bay Li-Ion charger like Intelli charger i4 and similars.

    To learn about batteries see: Battery Information Table of Contents, Basic to Advanced
    It is all there........

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    Great, I have an old trustfire charger but one indicator has gone and it seems awfully slow so its probably time for a new charger. I was looking at the Nitecore i4, only it says it doesnt detect the cell capacity, but im guessing this would still cut off charging unprotected cells around 4.2v?
    Fortunately im a vaper so all this stuff is extra useful
    Thanks again, ill check out the link and try to get my head around it all...

  15. #15
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    As a vaper you should already know something about Li-Ion cells.....

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    Well, I know as much about cells in vaping devices as i do about cells in bike lights - put in charger til it goes green; use til it doesnt work anymore, rinse and repeat...i.e, not a great deal. So your help is very much appreciated! Im having a band practice tonight and a few of the guys studied electrical engineering so ill see if they can clarify things!

  17. #17
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    Btw using cells till they "dont work anymore" is actually bad for them. Doing it once.in a while is ok, but everytime will ruin them, they last live less than half as long.

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    Thanks Tigris, thats worth knowing.
    Im testing all my old laptop cells in a Ultrafire 502b C8 torch (interesting item, incredible throw but lacks intensity) and the results are fairly consistent, on high setting the cells are losing about 0.5v every 30 mins so i guess theyre going in the trash (or the box in the supermarket for old batteries)
    Im also wondering how a SS case with good cells (like the Panasonic NCRs I linked above) compare to a good, mid-priced pack like this: Magicshine 4 Cell Hardshell Battery, MJ-6038A, B, C ? Action-LED-Lights (or something similar Gloworm for example)
    ??

  19. #19
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    Ss case protection is a fail (requires mods to make it actually work correctly). And how thin the wires are will cause the indicator on the lighthead to change colors (saying low battery) a bit sooner than it should.

    Dont get me wrong, the case works. Just not great and gotta be careful.

    I was about to recommend xeccon for battery packs but their prices have JUMPED MASSIVELY all of the sudden. Like battery packs buy as much as $40 jump in price.

  20. #20
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    Quote Originally Posted by tigris99 View Post
    Ss case protection is a fail (requires mods to make it actually work correctly). And how thin the wires are will cause the indicator on the lighthead to change colors (saying low battery) a bit sooner than it should.

    Dont get me wrong, the case works. Just not great and gotta be careful.

    I was about to recommend xeccon for battery packs but their prices have JUMPED MASSIVELY all of the sudden. Like battery packs buy as much as $40 jump in price.
    They seem extremely expensive for what they are. If i can get 4 x 3400mAh panasonic cells for $14 from GB, then a 6800mAh Gloworm pack ('built of 4 of the best Panasonic 18650 Li-ion cells') for $150 is pretty appalling value for money....i know there's some circuitry of some sort in addition to the cells, and the power indicator etc...but still that's a HUGE profit margin....is it not?

  21. #21
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    Not really, figure in cost of labor and time building the packs, sealing them, then the casing and then on some, the pouch. AND WARRANTY. Usually Panasonics are about $25 for a set of 4 (if you catch deals). All the other parts, $10-$12, then labor. So your up to $50. Hell the good protection boards are like $8-$10 for us alone. Them still costs at least half that as they dont use cheap Chinese boards. Then 1 warranty matter that profit margin is GONE.

    Gearbest is now going to carry Panasonic celled packs (they'll be sending me samples for review to be sure) and those are $25 for 4 cell pack. So its costing a $10 difference with everything being standard Chinese stuff, which is dirt cheap in comparison.

    That said $110 and $150 is a bit ridiculous. Xeccon previous price was $75 for a 4 cell, now $110.

    Alot of details most either miss or don't care about, just look at price. Even something like the voltage loss across cheap protection circuits vs good ones. Sometimes no different, sometimes a very noticeable one, which can make a noticeable impact on run time.

  22. #22
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    Great news about the GB panasonic pack! Wow. Looks like the search for a pack that isnt a) complete garbage or b) very expensive might finally be over. When can we expect this, do you have any idea?
    Thanks for the info

  23. #23
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    I should have them here soonish to make sure they are what they say.

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