Yep.... LiPo only gets down to 3.0V.
Still on a flight from China.
My tests on the Panasonic 3100s (this is the 3rd cycle)
You can just about see in my pic how a cheap blue trust fire did, shows how much better decent cells are...
My blue ultrafires did like 1200-1300 thereabouts. heh... The 2400 and 3800mAh ones... they came with my lasers.
You can't calculate the proportion like this. When comparing sizes of the cells (thus, the "mass" of electrolyte inside) you have to take into account cross section area or whole volume.
The cross section of 18650: 3.14*r^2=254mm2
and for 26650 we have: 3.14*r^2=531mm2
(I'm neglecting the insulation and case thickness).
From these rough calculations, it seems that 26650 has twice the volume (therefore ~twice the electrolyte) of 18650 cell. If it was the same technology as in Panasonic NCR, these cells should have ~6000mAh. ;)
Oh yeah....should use area instead. So after cycling a few times should hit like 4700mAh. So equivalent to a 2350mAh cell. Not too shabby yeah.
I mean the XTAR 2600s are also 2400+ @ 1A. I measured mine to be 2286mAh first cycle for the new purple label ones.
It is normal 18650 got more power per volume, millions of them are manufactured against few ones 26650.
Anyway it is not bad at all those 4525mAh.
Not bad? It got 4526mAh from the first cycle and it actually surpassed their rated capacity of 4000mAh @ 1A. Most of the 18650 cannot surpass their rated capacity, even when they do, it's 20mA, So the King Kong got with 13% more than rated, and the NCR18650A with 0.6% more than rated. And I doubt all NCR18650A will exceed their rated capacity.
I wonder what capacity will the King Kong give at 4A (1C).
Mitro said that his MNKE 26650 got over 4000mAh even @ 3A discharge, and since they are IMR, probably delivering high currents is not a problem.
Thanks 2100!
I mean not bad comparing their sizes against the Panasonic NCR18650A.
Let's see their volume differences.
Where the 18650 is roughly like this:
V= 3.14x81x65= 16532.1mm³
And the 26650 would be:
V=3.14x169x65=34492.9mm³
So,
3100--------16532.1
x------------34492.9
This gives us the 26650 should be 6467mAh which is much more than 4525mAh, so that is why I said it is not bad for a battery which is not as standard as a 18650 made by a company with a bigger R&D dept.
Volume of 18650 should be 66170 mm^3
Volume of 26650 should be 138059 mm^3.
That's 2.08x more volume.
Same 2.08x as compared to area. It's all mathematically relative to each other....
Sorry 2100, I don't get how you calculated those volumes, they are giving 2.0944X ratio not 2.08.
And yes, it is the same difference in this case with same height comparing Areas or Volumes.
I used 3.142
3.142 x 18 x 18 x 65 = 66170. To be more accurate, it is 2.0864.
I am talking about the money spent vs what you get. Discussing the volume is something theoretical and you have to choose the best from what you are being offered now.
The 2600 Sanyo ( 2400+mah reality) seems to be the standard not the 3100 from Panasonic. Let's say that 2500mah is ordinary and the King Kong are ordinary 26650.
2500--------16532.1
x------------34492.9
That's 5212mAh.
18 is diameter. Divide by two first before squaring.
2100, I understand then, you are getting the diameter*diameter, when the volume formula of a cylinder stantes it is radius*radius.
Hikelite,
The price relationship is quite good, and I got 26650s from MNKE and I am happy with them,but my point was just regarding their sizes nothing else than that.
I would love there were a model from panasonic with the same Watts per volume in a 26650 version, so I cannot compare equal to equal, just the best I know of each model.
I mean we were talking about different things.
Oh ok.... now i know where did i go wrong.
In reality, these are like Xtar 2600 capacity.
I'll see what they can do for 2nd cycle.
2100, Just two more questions.
Did you also check how many amps can they handle with?
And the last thing, I am also interested on the Palight protected ones ( http://www.goodluckbuy.com/palight-battery-26650-rechargeable-li-ion-battery-4000mah.html ) but to tell the truth I do not know much about them, I am not sure how good they are.
*Sorry if it is a bit off topic.
Those don't look protected.
They aren’t. My question is: what exactly are these? The wrapper say INR. Supposedly that is Lithium Nickel Cobalt Aluminium Oxide (or Dioxide - not sure). I know nothing about the claimed level of safety (or safe discharge/charge rates) of this chemistry.
So... I'll just go ahead and order a few for testing. I'm such a sucker for new cells. :p