Eneloop drain in Fenix TK40?

[AMD64Blondie]

I own a Fenix TK40,which I'm using Sanyo Eneloop NiMH AAs in. I just charged the batteries yesterday.
I'm going off to summer camp for a week,starting on August 8th,ending August 13th.

Will I be able to make it through the week without needing to recharge the batteries? (I'll be away from AC power,so I can't bring my charger-and I'd rather not risk using alkaline AAs in my TK40.)

 

[John_Galt]

Probably depends upon the usage. The TK40 does have a parasitic drain, but it should take much longer than a week to drain your battery's.

Off Topic:

Have fun at camp! I just got back from a week at summer camp, myself. Good Times...

 

[Locoboy5150]

You can do what I did to both my TK40 and now my TK45 to prevent any parasitic drain:

http://www.candlepowerforums.com/vb/showthread.php?t=257308

It's not the perfect solution as the plastic disk has to be removed every time you want to use the light, but it does work and it's free.

 

[Colorblinded]

I seem to recall that the parasitic drain is small enough that the light would have to sit for quite a long time (years?) before you'd notice it's draining your batteries appreciably. Of course, by then you'd be losing some of the charge on the batteries anyway.

 

[Nokoff]

sounds like you don't have spare eneloops or outlets at camp..that's why I love my 15 minute charger, find one and you're good in 15 or less..
If you're worried about the drain just loosen the tailcap.. though you would not notice drain in one week..
you know the published runtimes for the light, so it depends on how you use it..I've had much better than advertised runtimes using eneloops, say double

Have fun at camp, and I can see the future: you're team will win flashlight tag

 

[syncytial]

The parasitic drain in the TK40 was measured by HKJ at 400 uA (microamps). This was calculated to deplete the 8x AA Eneloops in 1.1 years (not taking into account the self-discharge of the cells.)

See: HKJ's page on parasitic drain.

So, don't worry about it.

Unfortunately, the term "parasitic drain" leads people to think it's some terrible design flaw - it isn't. It's better referred to as "standby current" and is there for a reason. The fancy interface with electronic switching requires it.

Like anything, a design can be good or bad, and there have been a few poor designs that would deplete the batteries in a light relatively quickly. This isn't one of them.

Syncytial.


P.S. - I have a TK40 that may have had it's batteries (Imedions) charged once in the last six months. It's still sitting at 5 volts - that's 1.25 volts per cell. It gets pulled out for brief usage at least a couple of times per week, and it doesn't get locked out.

 

[GrnXnham]

I own a Fenix TK40,which I'm using Sanyo Eneloop NiMH AAs in. I just charged the batteries yesterday.
I'm going off to summer camp for a week,starting on August 8th,ending August 13th.

Will I be able to make it through the week without needing to recharge the batteries? (I'll be away from AC power,so I can't bring my charger-and I'd rather not risk using alkaline AAs in my TK40.)

Guys, I don't think anyone here was asking about the "parasitic drain" of the eneloops caused by the TK40 in one weeks time.

The question was "eneloop drain"

The OP just wanted to know if his flashlight could last a week at camp.

I'd say he'd be fine. Set the power level to MEDIUM and use the light all you want.

 

[Colorblinded]

Guys, I don't think anyone here was asking about the "parasitic drain" of the eneloops caused by the TK40 in one weeks time.

The question was "eneloop drain"

The OP just wanted to know if his flashlight could last a week at camp.

I'd say he'd be fine. Set the power level to MEDIUM and use the light all you want.

Well if that's the case he should just consider the battery life he usually gets, how much he expects to use the light while at camp at each level, and go from there. The parasitic drain is too low and the LSD eneloops will last long enough unused that all he really needs to think about is how much and at what settings he'll use it.

 

[syncytial]

Guys, I don't think anyone here was asking about the "parasitic drain" of the eneloops caused by the TK40 in one weeks time.

The question was "eneloop drain"

The OP just wanted to know if his flashlight could last a week at camp.

I'd say he'd be fine. Set the power level to MEDIUM and use the light all you want.

Interesting point...


Regardless of what the mechanism of cell depletion is, the fundamental question is "Will the light be usable over a one week period?"

I think we've established that parasitic drain is insignificant.

My postscript in my previous post should allay fears about self discharge, albeit somewhat obliquely - i.e. self discharge is insignificant with Eneloops or other high quality LSD cells in the stated time frame.

The remaining consideration is runtime. We can quote specifications and reviews, but other than knowing the light can't be run for more hours than there are in a week, we can't say with certainty what usage it will get and thus how much time will elapse before the batteries are depleted. We can only offer the advice of using the lowest level that gets the job done (if the "job" is to impress others that may not do much good!)

• Turbo - 630 Lumens, 2 Hour
• Low - 13 Lumens, 150 Hours
• Medium - 93 Lumens, 20 Hours
• High - 277 Lumens, 6.8 Hours

- Syncytial.

 

[KiwiMark]

Turbo - 630 Lumens, 2 Hour

• Low - 13 Lumens, 150 Hours
• Medium - 93 Lumens, 20 Hours
• High - 277 Lumens, 6.8 Hours

So on medium it is good for ~3 hours per night for a week? That's probably plenty for most people, but as a flashaholic I would take a couple of backups. I like the 1 x AA lights because a 4 pack of Eneloops makes 4 sets of batteries.

If the OP has no backup available and just want to chance it with the TK40 then I would say that with mostly medium & low usage it is likely to be fine for the week.

 

[AMD64Blondie]

Sorry for bumping my own week-old thread...but I just returned from camp. My TK40 is still going strong.I love Eneloops.