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-   -   18650 battery 2600 vs 2900 mah (http://www.bikeforums.net/electronics-lighting-gadgets/699051-18650-battery-2600-vs-2900-mah.html)

balto charlie 12-03-10 09:02 AM

18650 battery 2600 vs 2900 mah
 
Hey all: I was reading on CPF about batteries. There is a discussion on the 2600 vs 2900 on high drainage. One poster feels the 2600 gives longer runtime with stable voltage so buying a 2900 might not be the way to go. I interpret this meaning the 2600 mah bats will stay brighter longer than the 2900 but won't last as long???? I'm not exactly an electrical geek so feel free to correct me.
Here's a link for the discussion. I don't believe the above point is valid but should be addressed in that forum:
http://tinyurl.com/25jp35o

Also there seems to be another god battery, Redilast. They are made in Korea and Japan w/ the IC being made in Japan

colleen c 12-03-10 10:22 AM

I will try my best to explain this without confusing you or me. Hopefully I don't give out misleading info so all are welcome to chime in and correct me :p

The character of 2600 vs 2900 are different. There is a slight nominal voltage between the two at the same load. This may indeed will change the lumens you get from your flashlight. However that will also depends on what led your flaslight is using.

Take an example of the good old P7. It is an older emitter that is not so efficient and draw a heavy load (amps). It is fairly bright at 4.2v but gets dim at 3.5 volts. A emitter like that probably runs better with a 2600 battery since a 2600 will hold a "useable" voltage longer under that current draw to produce a bright light. If you use the 2900 battery, it will drop into the voltage range where the lumens are diminish although there are still plently of life left in the battery. The reason is being that the battery has drop down in voltage where the P7 emitter will not produce the lumen it is rated for.

Now let's take a XP-G R5 led that produce 450 lumens and regulated. This led draws only about 1.5 amps and requires less voltage to produce the 450 lumens. It has a wider tolerance of voltage range to still be very bright. In this led flashlight, the 2900 battery will last longer because the flashlight will perform better even at 3.5 volt.

Makes sense? Or did I confuse ya even more :p

socalrider 12-03-10 12:15 PM

Colleen.. Great explanation..

The redilast cells are nothing more than relabeled Panasonic 2900 cells.. Which light will you be using these with??

I have had good success with Japanese Ultrafire 2600 and standard UF 3000's from this ebay vendor linked below. His prices are higher but he buys direct from Ultrafire.. I would say most of the UF 3000 and now 3600 cells on ebay are fakes or factory seconds.. I would not even consider the new 3600mah Ultrafires.. I have bought 2 sets of them and they are about as good as a 2500 mah cell in my opinion.. All the cells below are protected models..

Japanese 2600: http://cgi.ebay.com/ws/eBayISAPI.dll...=STRK:MEWNX:IT
UF 3000's: http://cgi.ebay.com/Ultrafire-Rechar...item56413ec99d
Panasonic 2900: http://cgi.ebay.com/Panasonic-NCR186...item5addb11eed
AW 2900:http://www.lighthound.com/AW-18650-P...ry_p_3671.html
AW 2600: http://www.lighthound.com/AW-18650-P...ry_p_3125.html

Pila charger: http://www.flashlightz.com/product.php?product=171829

tatfiend 12-03-10 12:36 PM

colleen c;

Per my understanding it is not the LED which is regulated but the drive circuitry for the LED which will vary from light manufacturer to manufacturer. In general Fenix and Olight lights have good regulation so maintain reasonably constant brightness through most of battery life while many of the cheaper lights such as those sold direct from China and some sold on ebay do not.

The new ANSI standard for listed battery life in a flashlight allows output to drop to 10% of full output by end of battery life, way too low an output to be acceptable IMO.

balto charlie 12-03-10 12:53 PM

Colleen: Thanks, I actually understand. It's kinda what thought but now understand more clearly.

@ Socal: I am going with the XP-G R5 so I will also buy the 2900 mah batteries. I did read that the Redilast were repackaged Panasonic. There was a vendor(seems reputable) on CPF selling them @$17 with fast and cheap shipping, that is why I brought them up. Your ebay link for the Panasonic's 2900 mah is really cheap!!! $22 w/ free S/H FOR 2:eek: Almost too good to be true. It's like half price.

socalrider 12-03-10 01:09 PM

Quote:

Originally Posted by balto charlie (Post 11881026)
Colleen: Thanks, I actually understand. It's kinda what thought but now understand more clearly.

@ Socal: I am going with the XP-G R5 so I will also buy the 2900 mah batteries. I did read that the Redilast were repackaged Panasonic. There was a vendor(seems reputable) on CPF selling them @$17 with fast and cheap shipping, that is why I brought them up. Your ebay link for the Panasonic's 2900 mah is really cheap!!! $22 w/ free S/H FOR 2:eek: Almost too good to be true. It's like half price.

I have bought from my fair share of Hong Kong vendors and so far he is the only one that delivers cells that meet there specs. If you check his prices, they are quite a bit more than most other vendors in HK.. The guy on CPF selling the redilast is a very good source.

balto charlie 12-03-10 01:12 PM

Quote:

Originally Posted by socalrider (Post 11881103)
I have bought from my fair share of Hong Kong vendors and so far he is the only one that delivers cells that meet there specs. If you check his prices, they are quite a bit more than most other vendors in HK.. The guy on CPF selling the redilast is a very good source.

Thanks, I'll put in an order for 2 and also buy a few from lighthound. Spread the stimulus money around:)

colleen c 12-03-10 02:08 PM

Quote:

Originally Posted by tatfiend (Post 11880930)
colleen c;

Per my understanding it is not the LED which is regulated but the drive circuitry for the LED which will vary from light manufacturer to manufacturer. In general Fenix and Olight lights have good regulation so maintain reasonably constant brightness through most of battery life while many of the cheaper lights such as those sold direct from China and some sold on ebay do not.

The new ANSI standard for listed battery life in a flashlight allows output to drop to 10% of full output by end of battery life, way too low an output to be acceptable IMO.

You are correct. The driver is the regulation of the led. Without it, the led will keep drawing current until it burns up in matter of seconds. There is a wide range where a led can operate. I think a SST 50 by Luminus is like 3.2v to 3.9v. I'm really not sure what most driver are design at but I'm sure it varies by manufactor. With a standard rating, things can be so much easier for us to choose.

I wonder will the China made flashlight will follow the standard ?..........

dougmc 12-03-10 03:06 PM

Quote:

Originally Posted by tatfiend (Post 11880930)
The new ANSI standard for listed battery life in a flashlight allows output to drop to 10% of full output by end of battery life, way too low an output to be acceptable IMO.

I've read those standards and found I just don't care.

It's not like they're "allowing" the light to get that dim -- it's just that that is the criteria they permit for giving it's runtime, that's all. Considering that most rechargeable batteries have their voltage degrade slowly as they're discharged, then drop fast at the end, and that LiPo batteries or lights need to have circuitry that turns it off before the voltage goes too low (or the battery gets ruined) I tend to doubt that the exact figure matters much -- 10% vs 25% probably means a small difference in runtime, for example. Even the time between 10% vs 50% probably isn't that large.

And remember, our eyes are not linear -- 10% of the light will seem a lot dimmer, but not 10x dimmer. Of course, you already know that ...


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