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…
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.
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!
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.
