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What battery is the best: 3,7 V 6800 mAh or 4,2 V 6000 mAh 18650 batteries?
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What battery is the best: 3,7 V 6800 mAh or 4,2 V 6000 mAh 18650 batteries?

What battery is the best of: 3,7 V 6800 mAh or 4,2 V 6000 mAh 18650 batteries?

Pretty sure that the real mAh is not 6800 or 6000, but still, is 3.7 V or 4.2 V better? And if the mAh numbers is true, what battery is the best. It from the same factory, and the price is almost the same.
Mostly using the batteries for torch and in a small phone charger.

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Comments

  • 3.7 volts are commonly used in power banks with a voltage booster circuit

    Thanked by 2myhken FlamesRunner
  • 4n0nx4n0nx Member

    I don't know anything about batteries but higher voltage may influence charging speed (if your phone supports it). Can anyone confirm/deny?

    ( Volt * Ampere = Watt )

  • @4n0nx said:
    I don't know anything about batteries but higher voltage may influence charging speed (if your phone supports it). Can anyone confirm/deny?

    ( Volt * Ampere = Watt )

    The input voltage for normal charging is 5V

    Unless granted the charger and phone supports Fast charging.

    Thanked by 14n0nx
  • 4n0nx4n0nx Member

    nexmark said: The input voltage for normal charging is 5V

    -> get 4.2V for faster charging then?

  • rds100rds100 Member
    edited June 2015

    It's the same. The Lithium cells are charged to 4.2V but the nominal voltage is considered 3.7V. Which one you claim / advertise is a matter of marketing.

  • It's the difference between the charging voltage and the target cell voltage that makes the current flow. The higher that difference, the faster the charge. The higher voltage battery will not charge faster. In fact given the same charger will likely charge slower.

    As for which battery is better, all else being equal, the higher mAh one is better. Unfortunately all else may not be equal. The design of the device using the battery may be better designed for one or the other.

  • @4n0nx said:
    -> get 4.2V for faster charging then?

    No matter what the USB output needs to be 5V
    What can increase charging time is the amps being delivered. Your regular laptop only delivers 500ma. Which is weak and won't charge as fast as 1amp or 2amps.

    Most phones will limit to 1 amp anyway.

    Thanked by 14n0nx
  • myhkenmyhken Member

    So for a power bank for my phone/pad 3.7 V 6800 mAh is the best choice. When it come to my torches it has little to say?

  • nexmark said: No matter what the USB output needs to be 5V What can increase charging time is the amps being delivered.

    The amps delivered will be higher with a higher differential as I explained above.

    If the charging source is USB, then the lower voltage battery will charge faster. As for which is better, we still don't have pertinent specs. And those are probably not available.

    Thanked by 14n0nx
  • rds100rds100 Member

    Also don't trust the mAh written on Chinese batteries. Chinese lie about such things 99% of the time. The 18650 batteries are usually no more than 5000 mAh.

  • SadySady Member

    You'll probably have to get something to step-up voltage to 5v at least & most of step-up converters has a good voltage range so either of these will work for you. For torch, it totally depends on lights being used.

  • myhkenmyhken Member

    @rds100 said:
    Also don't trust the mAh written on Chinese batteries. Chinese lie about such things 99% of the time. The 18650 batteries are usually no more than 5000 mAh.

    I know, but then it's better to buy a 6800 mAh battery that maybe has 5000 mAh, then a 3200 mAh battery that maybe has 2000+ mAh. The price I pay for 6800 mAh 4.7 batteries or 6000 mAh 4.2 V is around £1/pcs. (with shipping, and battery cases)

    I have used 18650 batteries for years now, and still, my old batteries, some of them more then 7 years old, is still working 100%. Of course, I have had some batteries that has died on me, and some DOA batteries, but still, good quality batteries to a low price.

  • @myhken said:
    I have used 18650 batteries for years now, and still, my old batteries, some of them more then 7 years old, is still working 100%. Of course, I have had some batteries that has died on me, and some DOA batteries, but still, good quality batteries to a low price.

    Just get the cells out of old laptop batteries, and chuck any that won't keep a charge or are below 2 volts when you find them ;)

    Like rds100 said it sounds like marketing in this case, as lithium packs are generally multiples of 3.7, with the cells in series. If you are designing something for USB charging from lithium stick with a single cell or cells in parallel for a nominal voltage of 3.7 volts as it's way easier to manage for charging and discharging/boosting.

    Another issue to be wary of is some of the cheap power banks don't have any MOSFET's for switching the battery from the output when it's empty at around 3.0 volts per cell, and just rely on devices such as phones to stop drawing power when the voltage gets that low. If you are attaching something dumb it could keep drawing power when the boost circuit is switched off (which by design has the input and output directly connected when powered off) and drain any batteries to dangerously low levels.

  • myhkenmyhken Member
    edited June 2015

    linuxthefish said: and drain any batteries to dangerously low levels.

    What can happen then? Can my phone be damaged, or just the batteries, or the power bank? or all?

    I have purcased theese power banks (to test who of them is the best)
    http://www.ebay.co.uk/itm/191267127048
    http://www.ebay.co.uk/itm/171526246222
    http://www.ebay.co.uk/itm/161656510586

  • vedranvedran Veteran

    rds100 said: Also don't trust the mAh written on Chinese batteries. Chinese lie about such things 99% of the time. The 18650 batteries are usually no more than 5000 mAh.

    What's much worse, a lot of those Chinese batteries are actually recycled old batteries or fake (as in not really 18650 but smaller battery put in 18650 housing).

    Thanked by 1netomx
  • myhkenmyhken Member

    @vedran said:
    What's much worse, a lot of those Chinese batteries are actually recycled old batteries or fake (as in not really 18650 but smaller battery put in 18650 housing).

    Yes, maybe true. But as I told you, I have really good experience with using 18650 batteries the last 7 years or so. The seller has almost 100% with several thousand sales, and I pretty sure which factory make this (since I have seen the wholesale on Alibaba.

    But I can be wrong, of course, that the good thing buying stuff from Ebay, I can get my money back at once if the batteries is faulty or they has way less mAh then stated.
    I will drain a battery in a torch, then charge it on a charge that tells me how many mAh and V it has charged the battery. So I will know it one day after I get the batteries..

  • myhken said: I will drain a battery in a torch, then charge it on a charge that tells me how many mAh and V it has charged the battery.

    Er, it's what you can get out that counts.

  • chouyuchouyu Member

    3.7V == 4.2V of 18650 battery.

  • SadySady Member

    @myhken said:

    Do share your experience.
    BTW as linuxthefish told, it would be best to get some PII or PIII dead laptop's battery & get cells from it. Those are usually high quality cells which are almost impossible to find now.

  • myhkenmyhken Member

    I asked the seller of the batteries, and he was honest enough to say that they are rated 5000 mAh ++, so you can get a difference of 1800 mAh. But still, it was time to renew my old 18650 stock now.

  • StevieStevie Member

    @myhken

    I remember bought 2 different 3000mah batterys but they were 550 mAH and 700 mAH LOL - they were junk - i complained and got a partial refund....

    But some stuff from china are good/decent I like the phablets lol I paid $30 for mine brandnew with sim card slot, bluetooth, 1g ram etc...

  • myhkenmyhken Member

    @Stevie

    I have some 5200 mAh batteries that I got from UK (of course they got them from China).
    Today I put one fresh charged battery in a 3000 Lumen torch (creed), that was around 10 AM. Now it's 11 PM, 13 hours later, and the torch still lights. Some weaker then in the start, but still so bright that I without any issue could have used it outside in the dark, reading a book, or what ever. 13 hours, and still going. Think I have to turn it off before I go to bed, so I can see how many hours it lasts tomorrow.
    But it can't be a bad battery series I got with the 5200 mAh Ultrafire gray batteries.

    Will compare with the 6800 mAh batteries when I get them (in 9-30 days). With the same torch.

  • InfinityInfinity Member, Host Rep

    Depends how efficient that lamp is, I would still doubt that you'd get the full claimed capacity out of it. You should measure the current draw and do the math. On the other hand, depending on the type sometimes if you're pulling more load it will turn off way before it's actually empty.

  • myhkenmyhken Member

    After 30 hours with the torch turned on (CREE XM-L T6 LED) the light was still going, but now at the most I could have used it to read a book, holding the torch in one of my hands.
    But when I took out the battery and tried to charge it, my smart 18650 charger quickly informed me that the cell was going bad. So it would not charge the battery.
    So that was one way to destroy a brand new battery? But then I know if I really need the torch one time and only have one battery with me, it will last a whole day running all the time. So for only short usage, then turn off, it will last for weeks.

  • myhken said: What can happen then? Can my phone be damaged, or just the batteries, or the power bank? or all?

    Below 3 volts you run the risk of the lithium bits or whatever creating an internal short circuit, which can lead to a fire when you try to charge it again!

    Read http://batteryuniversity.com/learn/article/bu_502a_over_discharging_lithium_ion

    Most people say if the battery voltage goes below 2.7 volts to not recharge, but to bin it. If you are in the habit of draining your torches to 0, buy protected cells that prevent overdischarge.

  • myhkenmyhken Member

    linuxthefish said: buy protected cells

    I always buy protected cells. That was I advice I got when I first started to buy 18650 batteries.

  • baranbaran Member

    lygte-info look here. There is no 6000 or 6800mah 18650 battery it is really fake believe me :).

    You can find torch and battery tests too browse the site i think you can find really helpful information from there. I recommend Panasonic 3400Mah NCR18650B you can find it on dx.com and read reviews.
    Good luck.

  • myhkenmyhken Member

    @baran since the test is from 2012, there has been a increase in mAh since that time. So if you are reading a newspaper from 1920, you can say that there is no computers or cell phones etc then? Still, the seller have checked with the factory, and they do not promise more then 5000mAh ++, so I totally fine with that.

    I got a small batch with Ultafire 5200 mAh batteries this week, and they was really good. And they are not on the list either.

    I think real life usage is more important for me then a "test". If the batteries works to what I need them to work on, then I'm happy. If not, I have not wasted too much money, since the price is only £1/battery.

  • myhkenmyhken Member

    Somebody here at LET that has some name of honest sellers at Alibaba.com? Want to try wholesale, but I bet there is 90% fakes and 10% honest seller on that site.
    But if somebody has got a good product from a seller, thats a good start.

  • There are no 18650 batteries that provide more than 3.600mah.
    It is physically impossible to get more with current technologies.
    Anyone using dangerously overrated lithium cells, is playing with his health.

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