And they say smoking is bad


Technology is often driven by request and demand, and while the drone community is growing rapidly, the number of people trying to quit smoking is probably a bit bigger. Along comes the E-Cigarette and with it, comes a demand for high current high capacity batteries - at low prices. I recently stumbled across such batteries (EFest 18650) that promised a 35A constant discharge and a capacity of 2500 mAh for as little as 6$ a piece in a shop that sells E-cigarettes and E-juice.

That sounded good, and while I don't smoke, I thought it would be fun to put two in my delta wing and see what it did to my flight time compared to my normal 2 cell 1300mAH lipo.

I charged the batteries using my lipo balancer and made sure they charged to the nominal 4.2 volts. I then constructed a small pack using a cheap holder for such batteries. The connectors and wires in the holder were, let's just say not that good, so I replaced them with something thicker to make sure no voltage drop was induced by poor quality.


I normally fly the delta with a small 1300 mAh lipo 2 cell, and at low cruising speed i usually get approx. 18-20 minutes of flight time.

I started out with my normal lipo, and got 18 minutes and 50 seconds worth of flight.

Then I exchanged the pack for the EFest 18650 battery pack. With a promised 2500 mAh capacity, I expected to get at least 50% longer flight time (accounting for the approx 30 grams extra weight of these batteries).


Sadly, I only got 15 minutes and 16 seconds! Thats worse than the half capacity 1300 mAh lipo!

I'm not the first to try out 18650 type batteries - made a nice test some time back - so why was I not getting same results?

After a recharge, I discharged the batteries and measured the capacity - I got 2040 mAh when discharging at 0.5 C, not 2500 as advertised. Further more it turned out that due to the low internal resistance of the batteries, the more power you draw, the more effect is lost as heat in the batteries - so at and amp draw of approximately 3-4, you end up only getting 1000 mAh of power - hence actually getting shorter flight times than a much smaller lipo.

I guess the lesson learned here is that these types of batteries are best in parallel, where the amp draw is distributed between several batteries AND you get what you pay for :-) For now I thing I'll stick to my lipos...

Most posts here are success stories and it's always very inspiring to read what others have accomplished - I would certainly love some feedback from others who've had experiences - good or bad - in using these types of batteries.

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  • the first figure is LG MJ1 and the second is NCR18650B

  • 3702225366?profile=original

  • believe me,LG MJ1 or NCR18650GA are much better,3500mah&10A  continuous discharge!

    and for ncr18650b,3400mah&4.875A  continuous discharge.easy to see the differences in the figures.3702225782?profile=original

  • 100KM

    @Jesper Andersen

    With the NCR18650Bs you should get some great flight times.

    The B version has the greatest energy capacity.    NCR18650B has 3200-3400 mAh.    The NCR18650A is 2900 mAh. You can search for NCR18650B or NCR18650A using Google and find the Panasonic data sheet for either battery.   

    Panasonic has quite a few versions of the NCR18650 battery.   Some have far last capacity.

  • @David James

    Ok - I probably need 6 amps for take-off and 2-4 amps during flight.

    I just ordered two NCR18650 - let's see how they perform.

  • 100KM

    The Panasonic NCR18650B batteries were the 3200-3400 mAh batteries that  were tested at My Geek Show.      I have tested the NCR18650Bs myself and found that they are pretty much what the Panasonic data sheet says and the My Geek Show found.  

    The NCR19650B datasheet from Panasonic shows the batteries capacity at discharge rates up to about 6 amps.   I understand that the NCR18650Bs have a thermal fuse that permanently disables the battery if 10 amps is drawn for very long.

  • A poor chainsaw gets torn down and some notes about 18650 types abo...

    Based on the notes from Chuck in that link, those are long life batteries (not specifically mentioning the quality of said cells) not power cells like a traction battery would want.  Other than being cognizant of how the industry is improving and knowing what capacities fit into what classes, I don't think there's any way of telling what cells fit into what category with just seeing the cell.

    A slice of a Nissan Leaf traction pack might be more up your alley if you have the payload for it.  Not on that wing, though.

    Beyond Unboxing: The Great Cambridge Chainsaw Massacre; Ryobi RY40511 Cordless Chainsaw | equals…
  • Li-Mn is an intriguing combination lacking the current of Li-Po, lacking the instability of Li-ion, with capacity in between.  The advantage is slightly higher power density without requiring a protection circuit.

  • Hi Jesper,

    The fact is that the E-Cig - Vape market has caused a whole lot of completely false 18650 style battery claims to be put out by a whole lot of completely unscrupulous manufacturers and distributors.

    It is basically just a pack of lies, very few of them deliver any enhanced performance at all and many of them actually deliver less.

    It has become an 18650 jungle out there and the only way to beat it is to stick to name brand manufacturers.

    But apparently even that won't work, because there is also a strong market in counterfeit batteries as well.

    Your test, has, in fact simply done a good job of confirming that this deception is a reality. 

    Best regards,


  • That battery box springs is robbing some jouice in the form of heat, better to solder good cooper wire or silver tabs...
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