If your using cheap crap ultrafires in the zy-t08, I find decent cells dropped the drive current from 3a to 2.4a, I now have a variable resistor to fit to sort this…. (i actually have ten, spares are useful, right?) :bigsmile:
Craig is the best. Goinggear is also great! I bought my Zebralight H600F from them. They gave me 12% off their normal price without even having a discount code. Really good seller.
Hi Gords
It’s good to have spares to compare your mods. 
Why would better cells be worse than the duffers I am using now? I know that there would be less demand on the batteries with a pair in parallel than in series but why would drive current drop with ‘decent’ batteries? I am pretty useless when trying to understand current versus voltage and stuff and would like to know more about the science behind this, preferably with simple analogies until I can get my head around this. Could you point me in the right direction, ie a link to somewhere where I can learn a bit more about the theory because at the moment I can only make comparisons with what I see with my eyes. I am waiting for delivery of a DMM and would love to know how to take tailcap measurements etc.
Thanks
Paul
I just got my USB battery box. Works great, both ports work with idevices (advertised as just one that would). Only prob is my protected cells don’t fit. Good thing I have a pile of laptop salvaged cells.
I don’t know the science, but the circuit is very resistance sensitive, I can put ultrafire Grey’s in, measure across the switch and get 3a, do nothing other than fit keeppower 3400mah cells or unprotected Samsungs, it reads 2.4a, the difference is noticable to eye I feel. It’s down to cell resistance I’m sure. You can however fit a potentiometer (variable resistor) across the sense resistor, it in the zy-t08 thread you need 0.22ohm ish (hence the variable resistor) you can then test and dial in the drive current you want on good cells. Needless to say, once set, you should stick to the same cells or test with new ones to be sure your ok.
It’s odd, and really counter intuitive, but doing nothing other than fitting crap cells really boosted my measured output.
Since you made me buy my first light on BLF almost a year ago that I’m still very happy with that’s good enough for me.
The reason is because your driver board wants a certain amount of power to deliver the right current to the LED. If your battery is a bad performer, you will measure higher tail current with the same emitter current.
In general, measuring tail current alone on a boost or buck driver is not useful. Your measuring input current, not output current. You need to measure emitter current as well. If the emitter current is where it should be, then a lower battery current is better.
On a DD or AMC7135 driver, it will give you an accurate measure of LED current.
Some day I’ll do a post on the various driver types and cover the basics of how each works. Essentially, we use four main types of drivers;
- Direct Drive: unregulated, (as simple as a piece of wire, better is a MOSFET with logic to allow PWM for modes), tail current = emitter current; power in = power out + resistive losses
- Linear: usually AMC7135 based; essentially, tail current = emitter current; power in = power out + circuit loss
- Buck: lowers voltage to match load requirements; tail current < emitter current; power in = power out + circuit loss
- Boost: raises voltage to match load requirements; tail current > emitter current; power in = power out + circuit loss
Edit: one curiosity here is the zy-t08 is 1s2p, so I don’t think it would be buck or boost. interesting…
2 - 10180’s from lighthound. Guess what for. (hint: I don’t smoke)
Are you going to make smoke with them?
2 AW14500's ready for when my SC52 arrives.
This light’s a beast. Amazing for its size and running on AAs!
Bought 5 led lenser flashlights and 3 emergency flares for $15.00. t5 with 1aa i really like, v2 3aaa, p7 3aaa, another still in pack that takes 3aaa and a very small k3 that takes the 4 ag13 also a nice little light. most of these are quick zoom even the k3. the t5 has a really nice beam and on the box it says that it converts the 1.5 volt aa into 4 volts.
sorry but did not know how to post the pic.
+1 could be one of the best lights of the year!!!
Holster for my Sky Ray King/ Fenix TK75
Today I received a package from a buddy across the pond. He only said he was sending me a light. Once I saw the big bubble pack envelope I knew there was much more than a light inside there! I'm very touched that someone I only know from a flashlight forum would be so thoughtful to send gifts, especially by way of international shipping! There are some wonderful people here on BLF!
-Garry
(Wiping tear from my eye.)
That’s awesome!!! This forum is filled with great people with large hearts!! It’s great to be apart of this big family!!! 
is that the TR-J18 from NZshooter giveaway? :bigsmile:
I’ll hazard a guess that its a custom light, a light the previous owner found extremely useful for its possible low output when a new baby wakes up in the night.
I’d say, go with the karma rule, pay the favour forwards in the future, it makes the world go round.
