TK70 problem sigh!!!

Had my tk70 for less than a month. i have brand new tenergy 10 000mah batteries. on turbo for 10 seconds, cuts to med then low and then it turns off! i dont know what to do anymore im so pissed at fenix they always had great lights. never had problems with them until this! is there an explaination for this? please advise . thanks

Sounds like a battery problem have you tried primarys or any other cells?

jhc37013 said:

Sounds like a battery problem have you tried primarys or any other cells?

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i have 16 brand new tenergy 10 000mah. dont think all 16 of them will fail right? ive also tried alkaline batteries too with same problem

I also think it's a power supply problem. Whether it's the cells, or if it's that they aren't being fully charged properly I don't know, and can't know without first hand testing. To see conclusively if it is the TK70 or the cells, connect the head to a 6.0V power supply that is capable of supplying at least 6Amps continuously, and preferably capable of 10Amps. If the constant voltage 6V power supply is connected to the head and it still does the same thing, it's the TK70. If it doesn't, then it's your cells, or your charger, or your charging method, or something else. Without further data, no one can say for sure. But you shouldn't get upset at the flashlight until you know for sure that it's at fault.

im using a maha 808 charger. since the batteries are new ive only charged them twice. then i conditioned the batteries but it still has the same problem. im not sure where to get a power supply to constantly put 10amps.....not familiar with this stuff

How long do they take to charge? Do you leave them in until they are "Done"?

Look here! http://www.candlepowerforums.com/vb/showthread.php?327611-Problem-with-TK70-or-Batteries

The Fenix TK70 requires top quality cells in good condition to maintain the turbo setting, but even if with less good cells or alkalines, it should be able to maintain the high setting for a while and would certainly not switch itself off immediately. I think there is something wrong with the light. You should return it for a replacement while you still can.

I use Tenergy 10.000mAh batteries too. Charge them in a Voltcraft P600 charger. No problems at all...
Mine TK70 has never failed me.

So it works allright in other modes?

If one of the batteries was suspect it could lead to the issues. Short of trying the batteries in another torch there is no easy way to load test the cells.

well.... now its not even turning on..... lol


sometimes it turns on, then i try to change the mode and it turns off

edit. posted same message

Send it back for repair, replacement or refund - absolutely shouldn't be doing this and this one must have slipped past QC.

Where'd you buy it?

Nyctophiliac said:

Send it back for repair, replacement or refund - absolutely shouldn't be doing this and this one must have slipped past QC.

Where'd you buy it?

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+1

Today I walking with my TK70 into the wood an I have the same problem. If I put the TK70 to torbo, the lamp fall back after 15 s to high. I use Ansmann 10.000 mA-Batterys. maybe, it ´s a problem of temperature. We had -1° Celsius.

I still think it's hasty and presumptuous to decide that the problem is either the TK70, or the batteries, without further data.
The problem could be either, and further tests would be required to narrow it down.
What if you exchange the TK70 for a new one, and it turns out you had a couple of problem cells causing the trouble all along?
You are unlikely to get sustained Turbo using any alkalines, they can't maintain the high current.
Good NiMh cells fully charged should be able to maintain the current, but if one or two of them are no good, the voltage of the whole battery would drop quickly, causing exactly the effect described in the OP.
When the load is removed, the open circuit voltage of the bad cells could bounce back, so even a voltage test after removing the cells from the flashlight might not necessarily identify the bad cell/s, if there are any.

To the OP: Do you have any friends with a hobby charger? Because here is a way to tell if the cells are good.
Charge them on your 808 the way you usually do,
Then one by one discharge them at a high rate, like 5A on the hobby charger and chart the discharge curve.
Have a look at the voltage that the cells maintain under discharge.
That will show you if they are keeping sufficient voltage under load (>1.2V) or not.
If all the cells perform well under that test, then you'll know you have a faulty TK70 and can then return it.
If you don't have any friends with a hobby charger, and you don't have a 6V power supply, then unless you can think of another way to track down the cause of the problem; you can't just assume it's caused by the flashlight or the cells.

Here's an example of some D cells discharged with a 4A load I did quite a while ago.
The Voltage levels shown are not exactly right though, because there was a significant voltage drop through the wires and connection to the cells.
You need to take a measurement at the cell under load and compare it to the hobby charger's voltage reading and the difference is the voltage drop, which should be added to the discharge curve voltages. (Edit: added chart with corrected data based on V drop and % of error in mAh readings that I have since calculated.)

samgab said:

I still think it's hasty and presumptuous to decide that the problem is either the TK70, or the batteries, without further data.
The problem could be either, and further tests would be required to narrow it down.
What if you exchange the TK70 for a new one, and it turns out you had a couple of problem cells causing the trouble all along?

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Yeh really that would be an expensive mistake considering shipping cost, know one who is having this problem has said whether or not they have tried the light with primarys. They may not hold turbo long but should be long enough to figure out if the problem is with the NiMH's your using.

wow thank you all for all the infomation! unfortunately, i dont know anyone with a hobby charger. seems like im the only one who loves flashlights in my circle of friends.

Profi58 said:

Today I walking with my TK70 into the wood an I have the same problem. If I put the TK70 to torbo, the lamp fall back after 15 s to high. I use Ansmann 10.000 mA-Batterys. maybe, it ´s a problem of temperature. We had -1° Celsius.

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did u try it indoors to see if it works normally? please let me know!

o i bought it at warriors and wonders

Ive got the same batteries 8 of them. Works fine indefinately on turbo. But... there are irregularities between lights (and Tenergy batteries for that matter). Fenix has just dropped the quality when it came to this light. Opening the box was a big disappointment. My heart sank when I saw dust in the reflectors and on the outside head. Felt like an old light. The laser etching was faded (evenly) and when I went to gently wipe the lens/glass with a damp cloth, my jaw dropped when I saw a drop of water trickling its way down towards the LED which was on. I was thinking waterproof huh? IXP nothing. And then it hit me, short circuit 4 x 10000 mAh batteries! Holy crap run! (turned it off first.) Definately an indoor light for beside my bed. Not for walking in the rain. But the batteries are definately not the problem unless you got a bad batch. I'm thinking the drivers.