Fenix TK60 with alkaline D-cells in an emergency?

Hi everyone, sorry if this has been posted before. I searched before I posted this, but there seems to be a lack of interest in the TK60 in general on here. Maybe I'm the only one with something of a fetish for big lights? Regardless, I'm considering picking one up tomorrow but I had a quick question. While I plan to use NiMH cells in the light most of the time, what kind of performance could I expect with disposable alkaline cells? I was thinking that in an emergency situation like an extended power outage, I may not be able to charge up my NiMH's, leaving alkalines as the only option. Would runtime/output suffer to the point where it renders the light unusable? From what I understand, running a TK60 on alkalines is not at all recommended. Could anyone confirm or deny this for me?

Thanks for your help,
Dustin

In an emergency situation I see no reason not to keep some around for reasons you mentioned. I am not sure how well they would handle the full output of the light, but you would probably be going for runtime not brightness if you needed light for an extended period of time. I would stick with the lower settings using them. I have a TK70 and would use alkalines in it for the same reasons if I had to. If I needed a light in the darkness just 50-100 lumens would be more than enough and the light would run a long time! Just do not forget to take them out after you use them!!!! I would hate to see leaking alkalines ruin such a good light!

It propably works without problem with alkaline but the brightness, at least at highest mode, will drop pretty soon compared to NiMh batteries. For use at the lower modes alkalines should work as good as, or almost as good as NiMh.

Pshhh... Go for it man. I've said similar things before in other threads here. Everyone is so focused on the latest emitter that squeezes out 10 bajillion lumens (<--- actual scientific number) that people forget that until just recently even 150 lumens was a really high output for a small hand held light. And in many ways 250 lumens or so IS the perfect "tactical" light for on person carry.

Anyway, D cell alkalines are definitely more than capable for very long run times with modern led lights.

Honestly what you are looking for is exactly the reason I got a Fenix E50. It was/is my first 18650 high output light (uses 2 or 1 18650's). The medium mode at 236 lumens is the sweet spot. It won't overheat there and you get more than 8 hours at that brightness with 18650's or cr123's (which I keep a box of for emergencies).

I think if Fenix ever just "upgrades" the TK50 and puts an xm-l2 into it it will be a VERY good light. That would be an awesome gift light actually.



A cool light you should check out if you are just looking for an emergency light that uses D cells is the new Streamlight Siege. The ratings are of course crazy as listed because they rate it to 10 percent output or some balogna, but it still looks like an awesome led lantern. It's not overly expensive either so it might be an awesome option for you. I think it's under 40 dollars so you could use the saved money to buy D alkalines and/or a D NiMh charger and D NiMh batts.

Thanks for the quick responses guys. Looks like I'll be good to go then. I can't really see why I'd need to use the 800-lumen turbo mode very often besides just playing around with the light (which I'm sure I'll do a whole lot of actually - that's half the fun after all, right?). I have a 220-something-lumen LED mini-Mag that is more than adequate in terms of brightness for general use in my area. I live in some pretty thick woods, so for the most part, I don't need to do much long-range spotting. Not that having the capability is a bad thing, since, after all, you never know

I'm pretty new to the whole flashaholic community so I still have alot to learn. Again, thanks for the help!

dustin1115 said:

I'm sure I'll do a whole lot of actually - that's half the fun after all, right?)

Click to expand...

I think you are very right here! Maybe especially with a thrower light like TK60.
By the way: Welcome to CPF and enjoy!

At room temperature, with the extender [4 D-cells] you will have no problem with the 350 lumen mode. (or any lower mode)
Don't even bother with the 800 lumen mode.

I own a TK60, and it runs just fine on alkalines. High mode actually puts out reasonable light for a good length of time. In medium and low mode it chugs along just fine, for ages and ages.

Turbo mode will work, but if you're using it just for spotting, it'll last a while. High mode is actually decently bright if there's no ambient light from street lights and such.

I don't know where you guys are getting your alkaleaks from but I can get full power turbo for 2 hours in my tk60.
It will not run full power on 3 cells. Turbo on 3 cells is barely brighter than the 300 or whatever lumens mode. I did get Tenergy Centuras to keep in the light and since I get all the alkies I want free , I keep some around for back-up or extended usage.
The Tenergy Centuras and the Premiums will run full brightness on 3 cells but I never actually did a runtime test on 3 cells.

The best thing about the TK60 is the impressively long runtimes. Like 4 hours on turbo with good nimh cells and 12 or more hours on high and something insane like 400 hours on low.

I seriously doubt that you are getting full output from 4x D cell alkalines for that long, even at 100F.
The TK70 will only run on its high mode on 4x D alkalines for less than 30 minutes. Granted that mode is 930 lumens vs. 800 of TK60.
So that slight reduction in power draw, ~10%, isn't going to quadruple your runtime. If you get 45 minutes on Turbo from 4 Ds with the TK60, be happy, then remove cells to prevent puking.
http://lygte-info.dk/review/Review Fenix TK70 UK.html
http://www.candlepowerforums.com/vb/showthread.php?64660-Alkaline-Battery-Shoot-Out
You are going to have to extrapolate what a 2 amp draw curve with alkalines is going to look like.
Ideally a 1.5 amp, then 2.0, and finishing with a 2.5 amp (2.5 amp x 0.9 volt/cell x 4 cells)