Sudden short run time on two batteries- Mtbr.com
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  1. #1
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    Sudden short run time on two batteries

    I have been running two clones on my night rides. On my two most recent rides, both batteries cut out around 45 minutes or so into the ride. Knowing the kind of quality issues people have had with these batteries, I wouldn't be surprised to have one battery crap out, but to have two batteries have the same issue at the same time is kind of weird to me. One battery is a couple years old and the other is only about a year old. When I charge the batteries, they juice up in about an hour, which is quite a bit shorter than I'd expect on a depleted battery. I only have one charger. Is it possible the charger is cutting out before the batteries are reaching full charge? Any other ideas or things I could try before buying new batteries?

  2. #2
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    Besides trying a different charge (the cheap chargers can do all kinds of stupid stuff) nothing else you can really do. But if your constantly running them till the protection cuts them off then good chance their bad.

  3. #3
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    The batteries have rarely been run to shut-down. Other than the past couple rides, they've only reached that point once when I was testing run time and maybe one other time. My rides are usually only around an hour, so they usually have juice left over.

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    Measure the pack voltage when the charge is done. Depending on how you batteries are configured, they should be 4.2V or 8.4V. If they measure like 4V or 8V, then your charger is shutting off too soon.
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    It's also possible that the cells have come out of balance. Your charger may then reach "full" when the first cell reaches 4.2v leaving the second (or others) cell lower. This was the case with my GearBest 3X light I reviewed. I think I posted pics showing how I individually charged them with a 4.2v charger to rebalance them. Are you willing to carefully tear open the pack (the heatshrink wrap) and measure voltages of individual cells? (I'm assuming you have a standard 2S2P 4 cell pack.

    -Garry

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    Here's the link to the GearBest 3x light. Toward the end of the first post you'll see the pack teardown and my "rig" for charging/testing cells individually:
    http://forums.mtbr.com/lights-night-...ht-944406.html

    -Garry

  7. #7
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    Quote Originally Posted by Vancbiker View Post
    Measure the pack voltage when the charge is done. Depending on how you batteries are configured, they should be 4.2V or 8.4V. If they measure like 4V or 8V, then your charger is shutting off too soon.
    The 4-cell pack was reading 7.7V and the 6-cell pack was reading 6.5V, if that provides any clues.

  8. #8
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    Is that charged or after use?

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    Quote Originally Posted by garrybunk View Post
    It's also possible that the cells have come out of balance. Your charger may then reach "full" when the first cell reaches 4.2v leaving the second (or others) cell lower. This was the case with my GearBest 3X light I reviewed. I think I posted pics showing how I individually charged them with a 4.2v charger to rebalance them. Are you willing to carefully tear open the pack (the heatshrink wrap) and measure voltages of individual cells? (I'm assuming you have a standard 2S2P 4 cell pack.

    -Garry
    I read your post a while back. I don't know if I have all the equipment/expertise to perform surgery on the packs (one 4-cell, one 6-cell). I do have a multimeter, so I guess I could open them up and check cell voltage if that's all it takes. Not sure what I would be able to do after that though.

  10. #10
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    Quote Originally Posted by tigris99 View Post
    Is that charged or after use?
    Fresh off the charger...

  11. #11
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    Sadly you don't have another charger because before doing that id check them on another charger first. That low of voltage doesn't sound like cells to me, they should be about 8.4 on a dmm fresh off the charge. But dead/unbalanced cells will just loose serious run time on the pack.

  12. #12
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    What's the voltage you measure coming from charger just plugged into the wall? (Just watch you don't short it out.) Charger should output close to 8.40v.

    If you have a chance to try another charger I would. If you unwrap the packs & check voltages you can just wrap it back up with electrical tape. Not much danger to it so long as your careful with your test leads (it's easier than measuring voltage out of the charger!).

    -Garry

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    Odd that there is such a variance between the two packs yet both are lower than usual. Something is definitely off and the charger is at least part of the problem I would think. Im wondering if there is an intermittent short somewhere in the terminal or cable causing it to stop at a random point that's not voltage related

  14. #14
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    @ OP,

    Step #1 ) If you have a cheap Chinese charger buy another charger ( or borrow one from a friend ) . My bet is that it is just the charger that is causing the problem. When you get a new one you might want to also buy a surge protector just in case a surge in line voltage took out the first charger.

    Step #2 ) if the new charger fixes the problem, "Buy another one for back-up". When it comes to inexpensive electronics it always pays to have back-ups.

    It also pays to have a back up plan for any night ride. Personally, I take this idea to another level. Along with my two main lamps ( and batteries ) I always have a small 18650 battery torch on the bars just in case I forget a battery or forget to charge something ( or if the main bar lamp fails ). Along with the 3-mode XM-L torch on the bars I have an extra 18650 cell in my bag. Add to that I always carry a mini EDC AA-torch ( XP-G2) in my pocket for repairs. Lastly, if I'm using a cheaper Chinese lamp on the helmet I'll also carry along another 18650 ( XM-L2 ) torch for the helmet just in case something fluky happens to the helmet lamp and it stops working.

    Sometimes crap happens. Just a couple weeks ago I forgot to bring one of my main batteries. While I could of done the ride with just one lamp it was not necessary. I took the battery for the helmet and used it for the bar lamp. I then took the helmet lamp off and replaced it with my back-up helmet torch....problem solved. Rare that I forget to bring something but it happens and yes it has happened before. No doubt it will happen again.

  15. #15
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    Quote Originally Posted by garrybunk View Post
    What's the voltage you measure coming from charger just plugged into the wall? (Just watch you don't short it out.) Charger should output close to 8.40v. -Garry
    Charger reads right at 8.40V or maybe 8.41V, I forget. I'll try a different charger. I just don't want to start buying stuff all willy nilly. I have a limited biking budget at the moment.

    Quote Originally Posted by Cat-man-do View Post
    It also pays to have a back up plan for any night ride. Personally, I take this idea to another level. Along with my two main lamps ( and batteries ) I always have a small 18650 battery torch on the bars just in case I forget a battery or forget to charge something ( or if the main bar lamp fails ). Along with the 3-mode XM-L torch on the bars I have an extra 18650 cell in my bag. Add to that I always carry a mini EDC AA-torch ( XP-G2) in my pocket for repairs. Lastly, if I'm using a cheaper Chinese lamp on the helmet I'll also carry along another 18650 ( XM-L2 ) torch for the helmet just in case something fluky happens to the helmet lamp and it stops working.
    Yeah, the first time my lights went out, I forgot a back-up. The bar light went dark, and I was just going to hit a downhill section before doing a short jaunt up to my car. I was less than half-way down the hill when my helmet light went out. Total darkness. I hit the brakes fast. Luckily, I had quick access to the road where my car was parked.

    I thought maybe this was a fluke or that I hadn't charged my lights up before putting them away the time before, but I made sure to carry my Serfas True 250 (my commuting light) just in case. When the other two lights went out, that Serfas was awfully dim, but at least it got me out to the road and back to my car.

  16. #16
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    Hmm . . . would love to hear what individiual cells measure . I'm placing my money on either faulty protection circuit (cutting off early) or more likely cells out of balance (perhaps 1 or 2 with very little capacity while other 1 or 2 still decent). Or perhaps all the cells have had their capacity drop significantly (still doesn't explain the odd voltage off full charge though).

    Here's a link to a decent Chinese 8.4v Li-Ion charger (thanks to ledoman): http://www.ebay.com/itm/141317775310 . Pickup a couple as spares.

    -Garry

  17. #17
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    Quote Originally Posted by garrybunk View Post
    Hmm . . . would love to hear what individiual cells measure . I'm placing my money on either faulty protection circuit (cutting off early) or more likely cells out of balance (perhaps 1 or 2 with very little capacity while other 1 or 2 still decent). Or perhaps all the cells have had their capacity drop significantly (still doesn't explain the odd voltage off full charge though).

    Here's a link to a decent Chinese 8.4v Li-Ion charger (thanks to ledoman): http://www.ebay.com/itm/141317775310 . Pickup a couple as spares.

    -Garry
    Garry, I'm sure there could always be other problems with the batteries ( depending on how cheap they are ) but the fact that "both batteries" are doing the same thing at the same time has to be more than coincidence. If both are using the same charger that is the common element. Replace the charger and if that doesn't bring both batteries to at least 8 volts ( and provide at least a couple hours of runtime ) than something else is going on.

  18. #18
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    Any update on this? I'm interested to hear your conclusion (or at least what you're finding out along the way).

    -Garry
    "My Bike Lights" Thread on BLF teardowns, measurements, and beamshots. Moving my photos, PM or post up if you can't see them.

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    Garry, I actually just packed up a couple chargers that I'm mailing to him. Hopefully it solves the problem but at least if not it's always nice to be able to charge multiple batteries at once. I'm running a bit behind on shipments cause the mrs. Was in the hospital

  20. #20
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    Sorry to hear about your Mrs manbeer. s0ckeyeus, keep us in the loop on how these chargers help or don't help you.

    -Garry
    "My Bike Lights" Thread on BLF teardowns, measurements, and beamshots. Moving my photos, PM or post up if you can't see them.

  21. #21
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    Yeah, manbeer said he'd send some chargers, so I have been on a bit of a holding pattern (not in a big rush). I am tempted to cut open at least one of the packs, but I haven't gotten around to it yet.

    I did go out for a ride last week, half before sunset and half after, and ran lights for about 1/2 hour. One pack cut out a couple minutes before I reached the car. I guess I'll have to hold off using that pack until I try out the new charger.

    I'll try to keep you guys updated. I appreciate the help.

  22. #22
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    Quote Originally Posted by s0ckeyeus View Post
    I did go out for a ride last week, half before sunset and half after, and ran lights for about 1/2 hour. One pack cut out a couple minutes before I reached the car. I guess I'll have to hold off using that pack until I try out the new charger.
    Sounds like your pushing your luck! Hope your carrying a spare pack or at least a flashlight!

    BTW - did you ever tell us what packs these are (i.e. where they came from)? Typical cheap pack included with a Chinese light? Specific link sold on Amazon? Supposed name branded light set?

    -Garry
    "My Bike Lights" Thread on BLF teardowns, measurements, and beamshots. Moving my photos, PM or post up if you can't see them.

  23. #23
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    Quote Originally Posted by s0ckeyeus View Post
    The 4-cell pack was reading 7.7V and the 6-cell pack was reading 6.5V, if that provides any clues.
    I went back to re-read this thread and saw this...^. You later said this was fresh off the charger. While the charger could indeed be bad it is also quite possible that the plug wire ( on the charger used to plug to the battery ) has an intermittent break in the wire or plug. This would help explain the two different charge voltages fresh off the charger and why both aren't getting a full charge.

    Since you are using two lamps and both of those seem to be working I wouldn't think there would be a problem with either of those wires/plugs. Anyway if you get a new charger you get a new plug/wires so pretty much a moot point.

    You might try charging one of the batteries and when the charger indicates a full charge, take the battery off the charger and move the wire around some on the charger. Then once again plug the battery into the charger. If the indicator on the charger shows that the battery is once again charging likely there is a bad wire on the plug and really nothing wrong with the charger itself. Going forward, intermittent breaks and shorts in these types of set-up are quite common. This is why when you disconnect battery from charger or battery from lamps you ALWAYS do so by holding onto the plugs themselves, not the wires.

  24. #24
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    Quote Originally Posted by garrybunk View Post
    Sounds like your pushing your luck! Hope your carrying a spare pack or at least a flashlight!

    BTW - did you ever tell us what packs these are (i.e. where they came from)? Typical cheap pack included with a Chinese light? Specific link sold on Amazon? Supposed name branded light set?
    -Garry
    I guess I was pushing it a little, but not too bad. Sunset is at 9pm here, and I could still find my way if need be at 9:30 when I was wrapping up (urban trail system). My back-up/commuting light, a Serfas True 250, was on the shower rod in our bathroom. We had an electrical problem and the light became our bathroom light source. It worked really well, but we were glad when the electrician came.

    As for my lights, the one light is one of the earlier XML lights I bought on eBay. It was one that popped up in a thread here that people were recommending, back when orange peel reflectors were a topic of discussion. I would suspect this pack to be the better quality of the two.

    The second light is a MJ-872 clone from eBay with a 6-cell battery pack from Amazon. It's a budget setup for sure, but it's served me well up until the past few months.

    Quote Originally Posted by Cat-man-do View Post
    I went back to re-read this thread and saw this...^. You later said this was fresh off the charger. While the charger could indeed be bad it is also quite possible that the plug wire ( on the charger used to plug to the battery ) has an intermittent break in the wire or plug. This would help explain the two different charge voltages fresh off the charger and why both aren't getting a full charge.

    You might try charging one of the batteries and when the charger indicates a full charge, take the battery off the charger and move the wire around some on the charger. Then once again plug the battery into the charger. If the indicator on the charger shows that the battery is once again charging likely there is a bad wire on the plug and really nothing wrong with the charger itself. Going forward, intermittent breaks and shorts in these types of set-up are quite common. This is why when you disconnect battery from charger or battery from lamps you ALWAYS do so by holding onto the plugs themselves, not the wires.
    I need to try this again. The charger came with my XML light. I actually had to swap out the plug on that light head because the wire had become loose. I sliced open the plug and found it was mostly just molded plastic and kind of a cheap connection. It's possible the same deal is going on here. I wouldn't say the charger has seen any abuse though. I'm pretty gentle with it, but it could just be cheap.

  25. #25
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    Cells are out of balance, no doubt to me. I'm 99% confident. Cheapo battery packs tends to do that sonner or later. Even with quality cells this will happen, but not so soon.
    It can happen on both almost at same time, why not. Measuring cells voltage would prove that and this is what you need to do.

    Newer charger won't help. You need to balance the cells, but this is only temporary solution as will come out of balance very quickly.

    So the best solution is: get you new quality battery pack or cells/case combo.

  26. #26
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    Ok. So I cut open my packs. Both are reading above 4.1v on the one side and 3.6v on the other. Guessing that means new batteries. Still kind of confused why both would go out at same time. I guess even if I could salvage these, it might not be worth it.

    I am thinking about going with the Solarstorm holder and get some more reliable cells and eventually a charger to charge individual cells. Any especially good deals on decent cells out there? Suggestions are welcome.
    Last edited by s0ckeyeus; 06-03-2015 at 04:18 PM.

  27. #27
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    Quote Originally Posted by s0ckeyeus View Post
    I guess I was pushing it a little, but not too bad. Sunset is at 9pm here, and I could still find my way if need be at 9:30 when I was wrapping up (urban trail system). My back-up/commuting light, a Serfas True 250, was on the shower rod in our bathroom. We had an electrical problem and the light became our bathroom light source. It worked really well, but we were glad when the electrician came.

    As for my lights, the one light is one of the earlier XML lights I bought on eBay. It was one that popped up in a thread here that people were recommending, back when orange peel reflectors were a topic of discussion. I would suspect this pack to be the better quality of the two.

    The second light is a MJ-872 clone from eBay with a 6-cell battery pack from Amazon. It's a budget setup for sure, but it's served me well up until the past few months.


    I need to try this again. The charger came with my XML light. I actually had to swap out the plug on that light head because the wire had become loose. I sliced open the plug and found it was mostly just molded plastic and kind of a cheap connection. It's possible the same deal is going on here. I wouldn't say the charger has seen any abuse though. I'm pretty gentle with it, but it could just be cheap.
    I took a look at the battery you linked to over on Amazon. Reviews were mixed but two of the reviewers reported "dummy cells" included in the pack. When I read that, "Bells and Whistles" went off! The 6-cell you have is of very questionable quality. Since you also mentioned the other as a "ebay" light special, that too I would also consider of questionable quality.

    When you get the new charger you can try to charge the batteries. If they indeed charge to 8-8.4 volts you might be able to use them for shorter rides. If you're lucky they will charge again and self-rebalance although this might take a couple cycles and there are no guarantees. Even if they start to provide better run times you should be wary of how long they are going to last. When you use batteries like these you are rolling the dice every time you ride.

    Going forward you should consider buying batteries of better quality from a more reliable source. If you want we can point you to a couple different sources, your choice. The price might be twice what you paid but you usually get what you pay for. The good news is that good Li-ion battery packs ( or separate cells to run in a cell holder ) are now more affordable. Nevertheless you will have to spend twice you paid for your Amazon battery to get a decent battery.

  28. #28
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    Wow 12.75 for a 6 cell...i can't believe amazon even allows crap like that to be sold on there. Need to start reporting sellers like that get them off their.

  29. #29
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    You can try to rebalance the cells like I showed in my GearBest light review link or even run the 8.4v charger across just the two low cells (difficult to do, a little unsafe, but possible). Your batteries are likely shot anyway.

    Beat bang for the buck has been protected Samsung 2600's from either Banggood or Fasttech (I'd go FastTech now that they sorted out a better battery shipping method). Use coupon "blf" for discount (I think it's sane st both stores).
    Lots of charger options. Xtar are great quality, reliable, and also pricey. The Nitecore i4 is probably best bang for the buck at about $15, but slow charging at only 375mA per bay with 4 cells loaded. Beware of fake Nitecore chages though. Take a look at Mountain Electronics, great US Seller: Mountain Electronics

    -Garry

  30. #30
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    Batteries are a crapshoot anyway, but Amazon is even more confusing with all the different sellers. Not all sellers are selling the same product. Some people on here were recommending the pack I bought, but I don't know if the seller is even on there any more. Oh well. I used rewards points anyway. The 4 cell pack lasted like 3 years, so I can't complain too much.

    Anywhere we can get the battery holders state side, or do they all come from overseas? Should a novice like me stick with protected cells? I've been rooting through threads around here, but it starts to get overwhelming.

  31. #31
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    Not that I am aware of. Best to stick with protected cells. The protection built into the SolarStorm box isn't very good.

    You could always buy a Hunk Lee battery on Ebay (ebay seller "Hunk_Lee" store = "FMA Battery").

    -Garry

  32. #32
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    All those packs come protected too, just a separate board in the pack vs on each cell. Works the same. Well should. Problem is price of the pack. Figure if the pack costs less than $5 per cell (in this case less that $30)and has multiple bad reviews fo issues, its a bad idea. Recommending a the of pack is one thing there are plenty of sellers that will make horribly fake copies just for the easy money. So its a crap shoot.

  33. #33
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    One Li-ion battery can only use half of a year with full power. Then it will be reduce the power step by step. You can use it for one hour when you buy it, only 30-45m after one year. When you don't use it, you keep it with some power. The quality of the battery is very important. The rate of decay is lower for the high-quality battery.
    The charger may be one problem. You can try to chanage another charger.

  34. #34
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    How is GearBest for batteries? I see these: 4 PCs Samsung ICR18650 - 26FM 3.7V 18650 2600mAh Protected Rechargeable Li - ion Battery (or these for a couple bucks more). With an Xtar VC4, 2 sets of 4 batteries, and 2 battery holders, total is $79.59, which won't make my wife happy but...

  35. #35
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    I'm not sure how GearBest is with shipping batteries. Stay away from the second ones. They are 4.30v cells. Issue is you'll only charge them up to 4.20v so you're not getting their full capacity. Their protection circuit is almost certainly set at 4.20+/- too.

    -Garry

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    Well, changed to the Intellicharger to save some money and found a promo code, so I'll see how things go with GearBest. Everything for $66.55. I'll probably still use wall chargers, but at least I'll have a charger to charge the cells outside the packs. Thanks for the help, guys. I hope this set-up works out better.

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