TN31 Standby Current Draw

[harro]

Hi Everyone;
I just want to relate an experience i've had with my TN31. You may or may not have experienced this, and this thread is meant to be IN NO WAY denigrating to the TN31, or Thrunite. I do use it fairly often and love what its capable of!!
Recently, there was a period of time where it sat idle for a period of about three months, and with Eagletac 2500mah cells that were about 90% charged. I normally store any electronic switched lights with head or tailcap ( whatever works for that particular light ) locked out. But this time due entirely to me forgetting to lock out the TN31's head, after that three months, it was dead. Ring was on standby and switch was off, but light not locked out. Remember, this is all my doing.
After checking into batteries and the hot side of cells, i learnt how to 'reset' the cell protection, but alas, all three showed less than 1.7v on my DMM, so erring on the side of caution, three new cells were procured and the old ones were disposed of in the correct manner.
As several highly regarded and experienced reviewers have stated, 'dont forget to store em locked out, or even remove cells when not using'.
I hope this saves someone the unnecessary cost of replacing cells, or, heaven forbid, something irreplacable.
Best wishes;
Mike.

 

[langham]

Thanks for the heads up, but I wouldn't chunk out some cells just because they got discharged. You can revive them by connecting them in parallel with a fresh cell for a minute or so and then throw them on the charger for a long charge. Why didn't the batteries protection circuit prevent discharge below the protection's limit? Isn't that what it is for? I was also under the impression that turning off the tail switch removed all current, as seen on another thread on CPF. They did some very precise measurements of the amount of resistance seen on the battery carriage of the light to include resistance with the switch in the off position and in STBY.

 

[harro]

Thanks for the heads up, but I wouldn't chunk out some cells just because they got discharged. You can revive them by connecting them in parallel with a fresh cell for a minute or so and then throw them on the charger for a long charge. Why didn't the batteries protection circuit prevent discharge below the protection's limit? Isn't that what it is for? I was also under the impression that turning off the tail switch removed all current, as seen on another thread on CPF. They did some very precise measurements of the amount of resistance seen on the battery carriage of the light to include resistance with the switch in the off position and in STBY.

Yeah, thats what i thought too, but evidently, when they drop too much below about 1.7v it can become a little iffy. I dont know the ins and outs of this, but i'm sure someone would.
As for the switch, i'd also heard that standby current is ment to be extremely low also ( 90ua-ish or so ), but...thats how it happened. On the TN31, the switch is electronically assisted, and itself, draws a current even when off. But again, there are others far more qualified than me to comment in depth about this. Many thanks for your input on this;
Mike.

 

[ma_sha1]

With some electric switches,I noticed that with increased humidity, it speed up the battery drain. When using humidifier next to my light, there was a huge difference observed, so I don't think mfg. spec drain rate is reliable if it depends on humidity so much.

 

[langham]

http://www.candlepowerforums.com/vb/showthread.php?337747-ThruNite-TN31-Review-(XM-L-U2-3-x-18650) This review is where I got my before mentioned data. If the switch is off then the resistance should be infinite, as it is not electronically assisted only the magnetic control ring is. There could be a slight short in your switch. As far as the batteries go I think it is always worth a shot no matter the circumstance, I have found that as long as it is greater than nothing they revive a good amount of the time. This is based on laptop cells that are unprotected.

 

[harro]

http://www.candlepowerforums.com/vb/showthread.php?337747-ThruNite-TN31-Review-(XM-L-U2-3-x-18650) This review is where I got my before mentioned data. If the switch is off then the resistance should be infinite, as it is not electronically assisted only the magnetic control ring is. There could be a slight short in your switch. As far as the batteries go I think it is always worth a shot no matter the circumstance, I have found that as long as it is greater than nothing they revive a good amount of the time. This is based on laptop cells that are unprotected.

Live and learn, i guess. Tks all for your info and seasons greetings to you.

 

[K9Patrol]

How is this possible? The off switch on the TN31 is a mechanical switch.

 

[harro]

How is this possible? The off switch on the TN31 is a mechanical switch.

Funny as it sounds, the switch does indeed have electronic assistance, and even when off, draws a very small current. So, even with magnetic ring in standby, and switch off, there is still a small parasitic drain. I know very little about these things, so my reference comes from someone far and away more learned in these matters, in this case, Selfbuilt.
The only way to truely break current draw in this light, is to physically lock it out.
Estimates seem to range from about 2 yrs to about 5 yrs on a good set of 18650's for standby/switch off, current. In my case it was about three months. Who knows, maybe i had a dodgy cell, or something not quite right in the light, but it doesnt affect normal day to day use/recharging. I just make sure i lock it out if i'm not going to be using it for a while ( as with all my electronic switched lights ).