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  1. #1
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    14.8v battery pack

    Hi
    I am looking for a lightweight 14.8v battery for my LED headlamp. I have read page after page on this forum (and others) the last couple of days and learnt a lot about batteries but I just want to make sure I did not misunderstand anything before I order online. I have started this new thread if someone else is looking for a 14.8v pack.

    So, first of all:


    Voltage: My heavy battery says 16.8v, 5.2Ah in the specs
    but as I understand it now this is the max voltage and because it is made of 4 x 26560 = 14.8v nominal, right?


    I have concluded that 4 x 18650 has the perfect weight/capacity combination.The Panovo holder is only 7.4v so not for me. I donīt trust my own soldering skills and I can not find a similar square 14.8v setup so then this seem to be my only option.


    It seems Panasonic 3400mAh unprotected is the best (long burn time) battery for this?
    Ordering from Banggood for example.


    I have a extra plug so I can solder that to the battery and just charge it with my charger (says 16.8v li-ion battery, Switching power supply, output: 17v 1A on it)


    I have also contacted ebay seller hunk_lee (waiting for reply) about a 4S1P version of his Panasonic bike pack.


    About balancing: As I understand a 4S1P pack can not be unbalanced?


    By the way, do anyone know why my lamp need a 14.8v battery when all the other use 7.4v (even Lupine Betty…)?


    Thank you for your help fellow riders!

  2. #2
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    Yep 14.8v nominal, 16.8v fully charged. I also have lights that use 14.8v, I just use rc lipo's. Probably a little heavier than the 4x 18650/26650 li-ion.

    example - Turnigy 5000mAh 4S 14.8v 20C /30C Lipo Battery Pack | eBay

    Cheaper than making your own pack and 5000mah off the bat so better capacity than you will manage with 4x 3400mah in series. check hobbyking for cheap lipos.

    Balancing - multiple in series = needs balancing. The lipo batts usually come with balance leads already attached, just need a hobby charger. 4s1p needs balancing, 1s4p generally does not as it is seen as just one large capacity cell although if one cell should fail...

    Put whatever connectors you want on the battery. I use XT60 connectors on my batts and lights.

  3. #3
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    Thank you for your answer! Yeah I was looking at lipos too, just did not get the discharge rate thing. I should mention that the reason for wanting a lighter battery (with less capacity) is that I am gonna use it for night orienteering and then every gram counts. I donīt mind paying a little bit more if I can save a few grams. I think around 3000mAh is enough for at least 1,5 h full light - I donīt need more than that. For cycling I can use the heavier battery if I need to. The lipos seem a bit heavier as you pointed out - 3000mAh = >300g while 4 x 18650 is around 200g.

    Hmm, but the balance thing makes me a bit worried - donīt know how to solve that...

  4. #4
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    The discharge rate is only really important for RC applications as if you have lets say a helicopter and you go full throttle the current draw might be 60Amps. So if you have a 30C 2200mA battery it can deliver a current 66 amps continuously ((30x2200)/1000)). A 10C 2200mA will deliver 22A continuously. Obviously we do not need to worry too much about C ratings with bike lights as the maximum draw will only be at most 3A, so as long as the battery can handle that draw you will be fine

    All lipo's will come with a balance lead and most of the ready made li-ion packs will have a built in battery protection circuit that will automatically balance the cells so don't require a balance lead. Most good hobby chargers will have balance leads and a lipo mode and also a li-ion mode. The main difference is you can only charge li-ions at 0.7-1A where as you can charge lipo's at 1C, so a 2200mA lipo can be charged at 2.2A

    Remember never charger battery's where they can start a fire if anything goes wrong. I use lipo bags as added safety but also charge my batteries in the shed.
    Last edited by brad72; 01-01-2014 at 06:27 PM.

  5. #5
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    I can't add to your rep again Brad, but thank you for the explanation of C on lipos. I have tried to find a good simple answer and have come up short so many times. :-) That spells it out perfectly!
    Fat guys need bikes too.

  6. #6
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    Thank you Brad for explaining the C rate!
    After reading other threads here I got the impression pcb:s rarely balance the batteries but just shut off the charging/discharging when one of the batteries reach the cutoff voltage... Someone mentioned Lupine smart core batteries to have balancing though. But maybe a ordinary pcb (like the battery holder I linked to) is enough?

    Looking at hobbyking the lightest 3000mAh lipo I can find is 299g and for 3300mAh itīs 337g. 4 x Panasonic 18650 (46x4=184) + holder (30) + wrapping and cables ≈230g at 3400mAh. (hunk_lee 7.4v pack is 193g)
    Low weight is more important to me than the possibility to charge a lipo faster (because I wonīt use it that often).

  7. #7
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    I have some 14.8v Tenergy propel packs with over charge/over discharge protection circuit and I just charge using a li-ion smart charger connected to the +ve and -ve leads and have never had any problems. Since the protection circuit had each battery individually connected to each cell they should all reach there peak voltage when charging. All my lipo packs are charged with a balance charger.

  8. #8
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    Ok, now hunk_lee sells a 14.8v batt made of 4 Panasonic 3400mAh cells! Iīll just go with that and forget the whole balance thing for now.

    Thanks for the help!

  9. #9
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    I have the opposite problem. I have a 14.8 battery pack and am looking for a head unit.

  10. #10
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    Yeah, dosenīt seem to be many of those around...I didnīt come across any when searching for battery. I bought mine in Sweden: Bikeray Sverige

  11. #11
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    Mine are homemade lights with 6x xpg-2 using maxflex drivers and the best solution was 14.8v.

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