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18650 Battery Comparison: Sanyo 2600mAh Vs Ultrafire 4000mAh

Fiddy

Fiddy

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G'day,

Just did some testing with 2 different brand 18650 batteries.

The laser i used was my 2W 445nm.

The laser was warm after some previous use with a different battery and i waited 5mins to let the laser cool down before the next test.

Each battery was fully charged to 4.2VDC before the test.

Sanyo 2600mAh
2600mAhBatterys.jpg


Ultrafire 4000mAh (Protection circuit removed)
4000mAhBatterys.jpg


  • Note there was a large dip in optical power at the 41 second mark on the Ultrafire 4000mAh battery., im not sure what caused this, i can rule out the laser moving off the LPM as it was dead still during the whole test.
  • I read that their real capacity is 1600mAh.
  • I also noted that with the protection circuit installed, it would'nt run the 2W laser at all.


These diagrams give a better explanation of 18650 batteries and their mAh rating.
Capacity.jpg


601ce946.jpg


Source: 2x Panasonic 2900mAh NCR 18650 3.7v batteries + case | eBay
 





Awesome tests dude!

ovb +1

Btw have you figured out the wiring for your guidesman?
 
Thanks man!

Yeah i did, the batteries (4000mAh funny enough) wouldn't run any of them because of the protection circuit! once removed they run splendid!
 
Rofl, I took the risk and ran a a-140 directly off a 4.2v (fully charged) cell and the protection circuit keeps the current down to a safe level :D

I think I will go for a boost driver with a 22600 battery in my hotlight so I dont have to worry about fitting cells in
 
haha nice, im not a fan of the protection circuit so i ripped em out :)

Interesting i haven't worked with a 22600 battery yet i wonder if they will fit my guidesmans!
 
Fiddy;

You have discovered the same conclusion I have, on most of the "low cost protection circuits".

They are poorly engineered.

They also consume power for the current sensing.

I agree with your numbers of ~1600mah for the Ultrafire 4000.

The Sanyo 2600mah cell has better construction, and much better durability.

The charts from Ebay do have a few obvious errors.

2 Watt 445nm diodes do require LOW internal resistance cells.

LarryDFW

P.S. Thanks for running the tests comparing the cells.
 
Last edited:
The ultrafire 4000 claim is clearly ridiculous, but i'm not surprised by that at all.

One interesting thing in the chart is the trustfire 2500, protected and unprotected. It seems the protection kicks in 300 mAh too soon, but the cell itself is not all that bad considering the low price.

One thing that is clear is that its no use to pay for whats on the label on cheap batteries like trustfire or ultrafire - seems to be other way around actually.

Its too bad these things are so variable - i've had some nonbrand laptop battery packs that were very bad, but the one for my HP is as good as the real thing and i payed less than 1/3rd for it.
 
LarryDFW said:
Fiddy;

You have discovered the same conclusion I have, on most of the "low cost protection circuits".

They are poorly engineered.

They also consume power for the current sensing.

I agree with your numbers of ~1600mah for the Ultrafire 4000.

The Sanyo 2600mah cell has better construction, and much better durability.

The charts from Ebay do have a few obvious errors.

2 Watt 445nm diodes do require LOW internal resistance cells.

LarryDFW

P.S. Thanks for running the tests comparing the cells.
Click to expand...

Thanks Larry!
What do you think of the Panasonic NCR18650 2900mAh Batteries?
or the newer Panasonic NCR18650A which claim 3100mAh?
It seems i cant find the 3100mAh's anywhere.
 
I think it depend on how they do the testing... I think if they use the battery @ 0.1A per hour until the battery is totally depleted, you might actually get 4000mAh (of course the battery will die), but when you are using 1A per hour, the Voltage will naturally drop then it will have something to do with internal resistance, (and they might actually charge their battery to 4.5V to do testing, it's possible, but it will damage the battery...)

There are alot other factors that needed to count in... what do you guys think? but of course I do agree the Ultra Fire doesn't have 4A... I think the battery company needed some guild lines for them to calculate the battery size, but then I think they is not gonna happen to Lithium Battery for a while
 
Absolutely, and this is also part of the problem: There seems to be no consensus of the testing method at all. Constant discharge at either 1 ampere or 1C would be a fair test for most applications.

There are some good examples of how to measure real usable capacity, for example the CIPA standard for digital camera's. It is an exact procedure that will result in a number of photographs taken before the battery dies. Given that the test uses flash every other shot and moves the zoom from wide to tele and back all the time, practical life will usually be better than what is specified.

Something similar could be done for just the batteries, to see how many mAh are actually in there given a specified electrical load (constant or even dynamic in a predefined pattern).
 
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