What gives highest power on a 26650 flashlight - 26650 battery or 18650 battery?

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myhken
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What gives highest power on a 26650 flashlight - 26650 battery or 18650 battery?

Hello.

Just a quick question. When using a 26650 flashlight, can 18650 batteries be better in some situations?
Etc: If I have two 26650 batteries 3000mAh and I have two 18650 batteries 3500mAh, what will give most power to the flashlight? Which setup can give the longest runtime?

I understand if I use 26650 batteries with 4-5.500mAh they will outperform 18650 batteries, that “only” have 3500 as the highest. (if you don’t think Ultrafire ratings is real Wink )

Kenneth Myhre

NikolaS
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LOL ! Just do the math 1+1=2 If you want better runtime 18650 will never outrun good quality 26650. If you want better performance in current then you should use HIGH DRAIN batteries and also then 4200Mah 26650 will be better then 2500mAh 18650

Ronin42
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Assuming that both sizes are charged to identical voltages, and have identical actual capacities then look to the resistance of each (lower is better).

Just to state the obvious, if one charges to a higher voltage that is an advantage and also if one has greater capacity that is an advantage.

If all your variables are too close to judge then the good news is it probably will not make a perceived difference, so you are good to go.

(“It’s good that most people can’t remember their previous lives. Otherwise
things would be a lot more complicated than they already are.”
Ajaan Lee Dhammadharo)

blueb8llz
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just get the purple efest 26650 3500 mah 32/64 amp battery are you are set!

thestug
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Aren’t two 18650s pretty much the same as a single 26650 assuming everything else is equal? I’d think the deciding factor between 2×18650 vs 1×26650 as far as output would be the IR and C-rate/max amp ratings.

texas shooter
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thestug wrote:
Aren’t two 18650s pretty much the same as a single 26650 assuming everything else is equal? I’d think the deciding factor between 2×18650 vs 1×26650 as far as output would be the IR and C-rate/max amp ratings.

Yes and no. Size wise it’s twice the volume. Quality wise it hits a snag. The best cells are generally Panasonic or Samsung, neither are pushing the envelope on 26650’s as they have done on 18650’s. If Panasonic were to produce 7,000 mah 20 amp 26650 cells the same quality as their 3500 mah 10 amp 18650’s many of us would be very happy.

Chicken Drumstick
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myhken wrote:
Hello.

Just a quick question. When using a 26650 flashlight, can 18650 batteries be better in some situations?
Etc: If I have two 26650 batteries 3000mAh and I have two 18650 batteries 3500mAh, what will give most power to the flashlight? Which setup can give the longest runtime?

I understand if I use 26650 batteries with 4-5.500mAh they will outperform 18650 batteries, that “only” have 3500 as the highest. (if you don’t think Ultrafire ratings is real Wink )


I think some of the replies in this thread are maybe misleading to your question.

In terms of discharge ability, as a trend larger batteries will have a higher discharge ability. This isn’t always true and you do need to look at the specific chemistries involved and the aims of the cell. e.g. a 3400mAh 18650 will most likely be an ICR and is designed to maximise capacity rather than discharge rate in this physical size. Hence why 2500mAh 18650’s of IMR or INR chemistries, will offer far higher discharge rates.

But given the same chemistry, a 26650 will always out perform an 18650 in terms of discharge.

This isn’t the easiest to see as the scales are different on these charts. But note, the batteries are the same chemistry from the same maker. The 26650 has significantly more capacity. But look at the actual discharge curve.

The 26650 is arguably flatter.

Also note the voltage at various discharge points. The 18650 drops to 3.3v quite a way before it’s final capacity, but the 26650 doesn’t drop this low until right at the end.


This all means a lesser spec 26650 can match or exceed some of the best 18650’s with relative ease, the trade off being physically bigger and having a lower capacity vs volume.

If you are comparing 2×18650 to 1×26650, then that is a different comparison and the matter of packaging vs performance becomes a bigger issue.

StorminMatt
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texas shooter wrote:
thestug wrote:
Aren’t two 18650s pretty much the same as a single 26650 assuming everything else is equal? I’d think the deciding factor between 2×18650 vs 1×26650 as far as output would be the IR and C-rate/max amp ratings.

Yes and no. Size wise it’s twice the volume. Quality wise it hits a snag. The best cells are generally Panasonic or Samsung, neither are pushing the envelope on 26650’s as they have done on 18650’s. If Panasonic were to produce 7,000 mah 20 amp 26650 cells the same quality as their 3500 mah 10 amp 18650’s many of us would be very happy.

Keep in mind that a ‘7000mAH Panasonic 26650’ would probably compare more with a 6000-6200mAH 26650 if you were to rate it like a 26650. Panasonic fudges their capacities somewhat by rating them down to 2.5V – a rather unrealistic rating. Considering that the highest capacity 26650s are now in the 5200-5500mAH range, they are really almost there when it comes to energy density.

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