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  1. #1
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    Battery discharging question

    I've been out of the night-riding scene for the past 10 years or so, but I've been excited to get back into it recently. The new LED lights are awesome, and I've set myself up with a Yinding paired with a 8.4v 8800mAh battery from amazon:

    http://www.amazon.com/gp/product/B00...ilpage_o05_s00

    The setup worked great for my inaugural 45 minute ride a week or two ago, and I fully discharged the battery afterwards, and then recharged it. I pulled it out this weekend, and it was dead when I expected it to be charged. I charged it on Sunday again, and after the charging cycle, tried the light on it, and it worked. I left it as it was, and put the light on it again this morning, but it was fully discharged. Is this normal? For a battery to discharge on it's own like that or did I do something wrong?
    http://www.mullenortho.com Braces and Invisalign in Leesburg VA

  2. #2
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    There are two possible explainations :

    1. The battery is a lemon. Lithium Ion has a relatively low self discharge rate. When fully charged, the self discharge can be elevated but this soon settles down as the charge drops a bit. Typical self discharge is around 1 to 2% per month.

    The rapid self discharge you are seeing suggests the battery has an issue and needs to be replaced. I would be very careful as a battery exhibiting this kind of behavior could swell up and catch fire if you charge it.

    2. There is some power draw from the light circuitry even though the light is turned off. You can check this by charging the battery up, then leaving it disconnected from the light. Wait overnight and retest in the morning.

    If you are sure 1. is the issue, buy yourself some new 18650's.

    Btw, fully discharging Lithium Ion batteries will reduce the number of charge cycles. Check out this site for useful tips on battery care

  3. #3
    EGGROLL!!!
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    I suspect that it is issue 1.

    The battery is disconnected from the light when it discharges, which did seem very strange. I'll try it one more time tonight (maybe charge it outside on the patio in case it catches fire!!!) and then look to replace it. Should I return it and get a new one, or get new 18650 cells for it?

    Thanks for the link on battery care, I'll check that out.
    http://www.mullenortho.com Braces and Invisalign in Leesburg VA

  4. #4
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    I would return it and get a new one exercising the 2 year warranty

  5. #5
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    You have bought cheapo chinese batery pack which is nowhere near 8800mAh. If it was it would need 4400mAh 18650 cells which does not exist even with the best companies like Panasonic.

    I think the pack is completly unbalanced. After charging check the voltage and report it back. Then we can tell you more .....

  6. #6
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    Quote Originally Posted by ledoman View Post
    You have bought cheapo chinese batery pack which is nowhere near 8800mAh. If it was it would need 4400mAh 18650 cells which does not exist even with the best companies like Panasonic.
    According to the link, the pack uses 4 x 18650, not 2

  7. #7
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    Quote Originally Posted by c8stom View Post
    According to the link, the pack uses 4 x 18650, not 2
    According to the link the battery is using quote>

    ...8.4v Li-ion Improved Water & Shock Proof Rechargeable PCB Battery Pack Spare Replacement (4 x 18650 batteries equivalent)
    I'm going to point out they use the word, "Equivalent". This means it might not necessarily be using 18650 cells. It might be 4 x 26650. When it comes to the Chinese, the word "equivalent" might be a way to sell a product that usually uses 18650's but not say it is not using 18650's. ( does that make sense? )

    Anyway, step one; Always test the cheapest option first. Get a new charger. If that doesn't work assume the battery is crap. Step two; buy a decent battery. If using it on a Yinding I suggest at least something in the 5200mAh range.

  8. #8
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    Quote Originally Posted by Cat-man-do View Post
    According to the link the battery is using quote>



    I'm going to point out they use the word, "Equivalent". This means it might not necessarily be using 18650 cells. It might be 4 x 26650. When it comes to the Chinese, the word "equivalent" might be a way to sell a product that usually uses 18650's but not say it is not using 18650's. ( does that make sense? )

    Anyway, step one; Always test the cheapest option first. Get a new charger. If that doesn't work assume the battery is crap. Step two; buy a decent battery. If using it on a Yinding I suggest at least something in the 5200mAh range.
    We can argue till the cows come home what equivalent means but with your anti-Chinese bias, am not even going to go there.

    Op should return the pack and get another and I wish him the best of luck with that.

  9. #9
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    Quote Originally Posted by c8stom View Post
    According to the link, the pack uses 4 x 18650, not 2
    Did you leave the battery plugged into the light? There can be significant discharge when the light is off.

    Interestingly it says 4 x 18650 batteries equivalent. Whatever that is. Its certainly a way overinflated spec. 4400 is normal for a 4 cell.

    In any case I would jump on the:
    100% 60 Day Money Back Guarantee No Questions Asked
    And then get a good battery and charger from Hunk_Lee or action led lights.

  10. #10
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    Quote Originally Posted by c8stom View Post
    We can argue till the cows come home what equivalent means but with your anti-Chinese bias, am not even going to go there.

    Op should return the pack and get another and I wish him the best of luck with that.
    ... Excuse me but you don't know me. I have no anti-Chinese bias. If I did I wouldn't be buying or reviewing their products. That said the Chinese are no different than anyone else but when it comes to translational issues within their product ads, they suffer greatly. I'm not saying they do this on purpose, it just is what it is. Sometimes there are words in English that don't translate well into Chinese ( and vise versa ) That's where the slang term "Chinglish" comes from. Other people ( as well as myself ) have noted the translational / word usage issues.

    I've been buying and reviewing lamps made by the Chinese for well....ever since the SSC P-7 emitter came out. Sorry but I forget what year that was.

    Anyway, the latest example of "Chinglish" is the Gearbest ad on the BT70. They recently added the additional choice of "lamp head only". Usually when they do this they will list a separate ad noting that it is "lamp head only on the main header ). This time they did things differently. They just modified the original ad and added an additional link ( within the ad ) using the phrase, "Simple set", which in my opinion is not being very descriptive. In order to find out what "simple set" meant I had to click on the link and read the entire product description. It turned out they used the same product description as the full set only where it lists the battery there is a note > ( battery not included ).

    Anyway, all of this is typical of the types of things you see on Chinese web site ads. If you spend any amount of time perusing the Chinese websites you would know about stuff like this. Believe me, all of this I consider a minor issue. By pointing out the word "equivalent", I was just trying to expand on the possibilities. Yes, the possibility exist that the battery is bad. I just didn't want to stereotype the seller as someone selling cheap Chinese batteries ( which is of course a possibility ). I like the Chinese so I don't jump to conclusions.

  11. #11
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    Quote Originally Posted by znomit View Post
    Did you leave the battery plugged into the light? There can be significant discharge when the light is off.

    Interestingly it says 4 x 18650 batteries equivalent. Whatever that is. Its certainly a way overinflated spec. 4400 is normal for a 4 cell.

    In any case I would jump on the:
    100% 60 Day Money Back Guarantee No Questions Asked
    And then get a good battery and charger from Hunk_Lee or action led lights.
    It could be using 4 - 26650 Li-ion cells. Those types of cells are in the 4000mAh-5000mAh range. At least that is how they are marketed. No way to know what's inside the plastic cover. Could be they are just normal 18650's and the seller is exaggerating the capacity of the battery ( which also would not be unusual ).

    Anyway, if they are 26650 cells it would just mean the pack would be a bit heavier. Keep in mind though that 26650 cells are generally not big sellers. *Usually when sold in packs they were previously cells sitting on a shelf somewhere that someone decided to get rid of because they are old. ( *my opinion )

  12. #12
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    Quote Originally Posted by c8stom View Post
    According to the link, the pack uses 4 x 18650, not 2
    You should learn bit more about parallel and serial setups and how to calculate capacity! This pack should be in 2S2P setup.

  13. #13
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    Quote Originally Posted by Cat-man-do View Post
    It could be using 4 - 26650 Li-ion cells. Those types of cells are in the 4000mAh-5000mAh range. At least that is how they are marketed. No way to know what's inside the plastic cover. Could be they are just normal 18650's and the seller is exaggerating the capacity of the battery ( which also would not be unusual ).
    2S2P battery packs with 26650 cells are very rare and I have never seen it in a hardcase shell. Very doubtfull and if you look the pictures it is tipical 4x18650 shape.

    It is classicl Chinese exaggerating and/or wrong calculation. There are noname 2200mAh cells inside at best.

    @eggraid101: Voltage after charging would tell the most about it's stage without dissassembling. Of course it should be returned, but would be nice to know it's stage for the other users. And if you ask me, I would take my money back rather to get another shitty pack.

  14. #14
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    From looking at the pictures of that Amazon battery, my guess would be it is really a 4400mAh 8.4v battery. I've seen those particular packs sold various places in 4400 and 6600mAh versions (4x18650 and 6x18650 respectively). I believe the 8800mAh designation is just a convenient misrepresentation on the proper way to calculate battery capacity... they've added up the capacity of the four 2200mAh 18650 cells without taking into consideration the 2S2P configuration.

  15. #15
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    OK. I've just got the identicaly looking 4 and 6 cells packs from Gearbest to test.

    6000mAh 8.4V 4 x 18650 Portable Rechargeable Water - resistant Battery Pack-12.62 and Free Shipping| GearBest.com
    8.4V 9000mAh 6 x 18650 Portable Rechargeable Water - resistant Battery Pack-16.67 and Free Shipping| GearBest.com

    4 cell pach had initial voltage 7.81V and 6 cell pack had 7.73V. Both were pretty fast charged with 2.5A chargers I've tested here: http://forums.mtbr.com/lights-night-...-944978-3.html

    6 cell pack finihed charging at 8.48V and voltage slowly drop down to 8.38V in two hours. 4 cells pack has some issues. It is charged only to 8.33V. Reconnecting it starts charge process again for a short period. This aplies the new pack was initialy unbalanced. Will prove that later this week when I plan to dissasemble both. Shurely will write complete review.

  16. #16
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    Quote Originally Posted by ledoman View Post
    OK. I've just got the identicaly looking 4 and 6 cells packs from Gearbest to test.

    6000mAh 8.4V 4 x 18650 Portable Rechargeable Water - resistant Battery Pack-12.62 and Free Shipping| GearBest.com
    8.4V 9000mAh 6 x 18650 Portable Rechargeable Water - resistant Battery Pack-16.67 and Free Shipping| GearBest.com

    4 cell pach had initial voltage 7.81V and 6 cell pack had 7.73V. Both were pretty fast charged with 2.5A chargers I've tested here: http://forums.mtbr.com/lights-night-...-944978-3.html

    6 cell pack finihed charging at 8.48V and voltage slowly drop down to 8.38V in two hours. 4 cells pack has some issues. It is charged only to 8.33V. Reconnecting it starts charge process again for a short period. This aplies the new pack was initialy unbalanced. Will prove that later this week when I plan to dissasemble both. Shurely will write complete review.
    On the 4-cell pack you have; That's not too bad for an initial charge. Some batteries where the cells are not really well matched will have some self-balancing after the initial charge. Charging it again should help re-balance the pack, at least for a short period depending on how bad the pack may be. Anyway, I consider a pack that charges to 8.4 to 8.38 to be normal.

    About the OP's battery; I think kwarwick hit the nail on the head. At first I thought the website administrator made the mistake in calculation but then I see that the capacity is marked on the battery itself. ( seen on this ad, same battery )

    Anyway, kwarwick's explanation is the most plausible. After looking at the photos of the different ( but similar ) packs on both Amazon and Gearbest it looks very likely the OP's pack is using 4 x 18650 ( based on size comparison ). I was just trying to figure out how they came up with the 8800mAh figure. There are 4400mAh 26650's but I've never seen them used with a plastic case before. I figured there's always that possible first time.

    Looks like we need a new Chinese slang term, "Chinrithmetic"? Oh no, now I've done it. I've gone all anti-Chinese again....

  17. #17
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    FYI. Over the night both packs have droped their voltage down to 8.30V. Quality cells would not have that much drop unless they are wornt out.

  18. #18
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    My Panasonic cells I put in my 880 case did that, forgot to do a full parallel balance (instead of series balance which never gets the perfect). Sounds like one side was way off. Just trying to give the packs "hope" lol.



    I am curious what it takes to open one of those up and if (with our skills) able to change cells to something proper but use the shell. Im coming to hate cases with built in protection. Already bypassed it on 2 of them lol. The protection in welded packs just seems far more reliable (doesn't trip do to brief connection loss from weak springs which ive had to fix too)

  19. #19
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    Yes of course, if they were not balanced before each pair rebalanced itself in the case. Keep in mind 880 case might also have some parasitic drain. Not shure about it, but I would check it out if you can.

    When I get home frpm job I'll make discharge test on 4 cells pack at 2A. This means 1A per cell. Will see how it will perform. I predict around 4000mAh at best.

  20. #20
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    No drain that I found, I just learned balance in series on my charger does not work as well as balance in parallel. I researched and found that balance in parallel is best for these kind of cells, at least before pack assembly (or installation in a case). Cells will perfectly match each other that way where as in series its reliant on the charger which can always have a slight margin of error. Or in the case of mine, a .23v margin of error.

  21. #21
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    Tigris what is your charger? I forgot it. Charging in parallel is of course the best. To get cells balanced you just need to connect them in parallel and they would balance themselves even without charging. This balancing method can be ocasionaly used if you charge replaceable cells in the cases with 8.4V chargers. From time to time you take them out after charging and put in the craddle like this (EDIT: added link) for few hours.
    Last edited by ledoman; 07-02-2015 at 01:14 PM.

  22. #22
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    Guys, the Stupidbright site selling those batteries is not Chinese though the cells are most likely are. Says Chris Evans Industries and the guy does his own videos, he's American. The label on the side of the case has a fake sku code.

    That said, it's a good case, same type MagicShine offers now, I've got one of their 4400mAh units with BAK cells, came with the latest MJ-816. Like how the rubber straps keep the pack from sliding around, much better than Velcro and easier to mount on/remove from frame. Looks slick on my black bike too. Wish hunk_lee sold his wares with that case.

  23. #23
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    Quote Originally Posted by andychrist View Post
    That said, it's a good case, same type MagicShine offers now, I've got one of their 4400mAh units with BAK cells, came with the latest MJ-816. Like how the rubber straps keep the pack from sliding around, much better than Velcro and easier to mount on/remove from frame. Looks slick on my black bike too. Wish hunk_lee sold his wares with that case.
    One warning: these new MS cases themselves are fine, but plastic buckles are fragile and tend to break within some time of use, especially in cold weather. Velcro bands were at least 100% reliable in my practice...

  24. #24
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    Ledoman

    I use an estation bc6. I have a cradle I made using 2x 18650 trays, just originally had them wired to charge in series. I changed that to parallel for balancing and use my nitefighter charger to do normal charging.

  25. #25
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    Quote Originally Posted by andychrist View Post
    Guys, the Stupidbright site selling those batteries is not Chinese though the cells are most likely are. Says Chris Evans Industries and the guy does his own videos, he's American. The label on the side of the case has a fake sku code.

    That said, it's a good case, same type MagicShine offers now, I've got one of their 4400mAh units with BAK cells, came with the latest MJ-816. Like how the rubber straps keep the pack from sliding around, much better than Velcro and easier to mount on/remove from frame. Looks slick on my black bike too. Wish hunk_lee sold his wares with that case.
    Thanks for the in-depth analysis of the cells.

    Yes, I have been in contact with the Stupidbright guy(s) and they have been very easy to deal with. I've already mailed it out for an exchange, so I think I'm going to start with that for now. What battery pack would you recommend from Hunk_Lee? I'd prefer something easy, plug-and-play type thing. Thanks!
    http://www.mullenortho.com Braces and Invisalign in Leesburg VA

  26. #26
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    Finished first discharge of a 4 cell pack. After one day rest I discharged it with iCharger 106B+ at 2A down to 5.6V and I've measured only 2198mAh. Since the pack is very likely unbalanced I would give it bit more, but not much.

    Here is the discharge graph:
    Curently I'm discharging 6 cell pack....

    Similar to the previous one the 6 cell pack has only 3273mAh. The voltage falls down so fast that protection trips in before charger realize it reached 5.6V. Discharge graph;


    Will follow up with teardown tomorow.
    Last edited by ledoman; 07-02-2015 at 02:51 PM.

  27. #27
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    Ha! You could put two very good cells in a Fenix case and come out better than those packs! (Well the 6 cell might be very close but it's 6 cells compared to 2!) Typical.

    -Garry

  28. #28
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    It wouldn't surprise me if both of those packs were running "dummy" cells. Anyway, all of this highlights the advantages of buying good batteries from a reliable source. This is why so many of us are asking for "lamp head only" sales.

  29. #29
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    Ya this is why im glad nitefighter actually uses quality cells. Be nice if other companies would follow that example.

  30. #30
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    All in all I just wanted to proof the pack from OP is more or less shitty expecialy for the price payed at Amazon. If you look at price from Gearbest you are getting nice waterproof case and good batery pack after you replace the cells and seal it back.

    Teardown has been done with screwdriver prying edge between the top and the body. To get to that point you can move ruber band to the bottom. Inside was welded pack with foam on every side to prevent rattling:
    Shrani.si

    It is good there is zip tye to prevent pulling cable out:
    Shrani.si

    The cells are unknow (no markings) with small protection circuit:
    Shrani.si

  31. #31
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    Quote Originally Posted by ledoman View Post
    All in all I just wanted to proof the pack from OP is more or less shitty expecialy for the price payed at Amazon.
    Can you weigh them? <40grams each likely means they are low capacity.

    Thanks to DX (and fake eneloops) for teaching me that battery trick.

  32. #32
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    At last stage I can do that. I plan to replace the cells with salvaged from laptop packs.
    The whole packs weights 258 and 356 grams respectively. From the difference you can't tell for shure are they less than 40gr or not.

  33. #33
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    Discharge graph of 4cell pack showing each pair of cells. You can see one pair is fairly good (ie. it has smooth curve) and the other is having some trouble.

    Shrani.si

    Will do the same for 6 cell pack..... After charging pack is unbalanced with 4.24V and 4.13V each set of 3.

    6cell pack is also having some issues and quite some difference between 2 sets in series.
    Shrani.si
    Last edited by ledoman; 07-04-2015 at 06:13 AM.

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