Which makes more sense: 2000nimh enerloops or 2500 nimh energizers in Fenix TK20?

[woodrow]

Help me out here guys... I have looked through a few pages of threads.... and I am not sure what batteries to buy.

I have (hopefully) a Fenix TK20 coming tomorrow. While I have plenty of e2 lithium AA's... I thought I would mainly use rechargables for the light.... and I see it getting almost daily use.

I know regular 2500 nimh duracells...or energizers drain mush faster then enerloops.... but the higher nimh batts will give me better runtime.

Should I still buy the pre-charged AA's for a light that is used on a bi-daily basis? Or does the higher nimh still win out as long as they are recharged at least once a week?

Thanks for your help!!!

 

[Marduke]

Avoid the 2500's like the plague. After just a few cycles they will discharge in a matter of days, not weeks or months like other "regular" high capacity NiMH cells.

Duracell 2650's are pretty good for high capacity, while Eneloops are good for general purpose if you want to "standardize" on one cell for the entire household.

 

[odessit]

I have (hopefully) a Fenix TK20 coming tomorrow. While I have plenty of e2 lithium AA's... I thought I would mainly use rechargables for the light.... and I see it getting almost daily use.

For daily use and frequent recharges I would get high mAh batteries.
For in-frequent use lights I would get Eneloops

I purchased 8x eneloops and 4x Sanyo 2700 batteries.
Eneloops are in my TK20 & L2D on standby duty and I have 2700 that I charge ahead of known usage. This way I get long term storage for emergency use and high capacity if needed.

 

[woodrow]

Thanks for the info.... It sounds like if I am using the light a lot... I would be OK with Sayno 2700's. Do the Sanyo batts self discharge as fast as old nimh AA cells did?

 

[Marduke]

Anything other than LSD cells will discharge at the typical NiMH rate. For most cells, this is about 5-10% per week.

 

[greenLED]

For daily use and frequent recharges I would get high mAh batteries.
For in-frequent use lights I would get Eneloops

Ditto.

Also, I haven't bothered with anything with higher capacity than 2400, just because cells with higher capacity seem to fail so much and so often. What's the point of spending (wasting?) money on 2700's if they're going to go south within a few cycles?

My 0.02 lumens (on depleted cells).

 

[mdocod]

Unless you absolutely think you NEED that extra 25% runtime available right after charging up the cells, then you'll still be better off with eneloops in the long run.

1. If you plan on having "spares" around you will always know they have plenty of useful juice left in them.
2. LSD cells, especially eneloops, hold a higher voltage under a load than most other consumer NIMH cells. The result is that the lower mAH rating does not have as significant a meaning as it would appear when compared with regular consumer cells when used in a "regulated" device like a flashlight. True capacity is measured in watt-hours, and eneloops are not as far behind "high" capacity cells as their label capacity would lead you to believe.
3. LSD cells are more robust than ordinary NIMH cells. They tend to have a much longer useful life, in terms of either storage OR cycle performance. If you were to take a set of Sanyo 2700s, and a set of eneloops, and cycle them each several hundred times, After the first hundred cycles or so, the eneloops would probably be performing BETTER than the 2700s. The number one reason to go rechargeable is to save money, and the best way to take that concept a step further is to invest in cells that will survive the longest.

-----------------------------------

If it were my EDC, it would be eneloops, for reliability and trouble free operation. High capacity cells require more maintenance.

 

[geek4christ]

+1 for mdocod's explanation.

Cells with low self-discharge are the way to go. I have some older conventional NiMH that I've almost stopped using entirely. It's just too much work to remember the last time they were charged, guess how much they might have discharged, etc. Life is short and we have flashlights to enjoy.

 

[woodrow]

Wow.... Thanks everyone.... I am so used to using lithium cells in my other lights.... nimh's are quite new to me. Thanks for explaining everything so that a non-engineer like myself can make a more educated decission that i can feel confident in.

I will go with the Enerloops.

Again, Thanks!