What's likely to be going on here (tail cap current issue)

[gcbryan]

I have two Ultrafire BJO8A lights using a single 14500. I've put an aspheric in one and a TIR in the other. Using the same battery one has a current reading (tailcap) of 800 mA and one has a reading of 650 mA.
Is this just likely to be differences in individual emitters and drivers?

This has nothing to do with the tail cap and switch since the readings are with the tail cap removed. I've wiped off the threads so there is nothing obvious to explain the difference.

Edit: After experimenting some more... the light with the higher current draw is dimmer than the one with the lower draw as measured with the light meter.
When I put the pill with the higher draw in the light with the aspheric the lux reading is less than when I match the aspheric head with the lower draw pill.
Would this be a combination of where the driver is less efficient but the emitter is more efficient (higher lux reading). Could the other pill with the higher draw have a more efficient driver and a less efficient emitter?

It's an odd outcome and it's very repeatable.

I even took a bare emitter reading from both lights and the light driven at 800 mA was dimmer than the light driven at 650 mA.

 

[moderator007]

More than likely the manufacturer has switched components of the driver or the driver all together. China has been known to do this from time to time. It all depends on the supply of the components they use. If they run out of a component. They will substitute it with something similiar but not always as good.
Also when I checked google for the ultrafire BJ08A, KD had it listed as 1150ma on high.

 

[gcbryan]

More than likely the manufacturer has switched components of the driver or the driver all together. China has been known to do this from time to time. It all depends on the supply of the components they use. If they run out of a component. They will substitute it with something similiar but not always as good.
Also when I checked google for the ultrafire BJ08A, KD had it listed as 1150ma on high.

I think your explanation is probably the correct answer. Regarding KD and listed specs...hahaha :) Are there any correct specs on any of these sites? I always just ignore the current spec since they usually don't even know what they are typing.

 

[moderator007]

I usually look for reviews before I buy on things i buy either from KD or DX. Some times you can find good info on there products here at cpf.
If it receives good reviews there still the chance that the product could change by the time you receive it.

 

[gcbryan]

I usually look for reviews before I buy on things i buy either from KD or DX. Some times you can find good info on there products here at cpf.
If it receives good reviews there still the chance that the product could change by the time you receive it.

The thing is this is a great light. I lucked up in my search for a single AA/14500 light that I could use as a small "thrower" along with my headlamp for hiking. I bought two and put an aspheric in one and a TIR in the other as well as putting in forward tail switches. This is a single mode light (there may be other options as well I don't know).

It has great heat sinking, a screw in brass pill, easy to change out head and tail switch.

Even the dimmer light is still plenty bright. I only noticed it because I just got a light meter and therefore checked out lux on both of them since they should be identical. When I saw they weren't I checked the tail current.

I got this at Tmart since I knew that I would receive this in about 5 days from ordering. Since the first one worked out so well and I knew I could get another quickly...I did.

If the KD version actually was 1150mA I'd love to have one but I don't want to wait a month to find out it's just like the two I already have.

If someone on here has one from KD and can measure the tail current that would be much appreciated. If they have a light meter that would be even better!

 

[moderator007]

If it were me I would order something like this. They also have AMC 7135 boards without the modes if you prefer. Mod both the lights with the new driver. They will only work with the 14500 then. But they are a very efficient driver for single cell lights. They are 17mm boards so they should fit. May take a small amout of sanding on the outside of the driver to make it fit the pill.
You can choose between 350ma to 1400ma for the single sided board. Each AMC 7135 will give you 350ma of current. They are in parallel. You can buy the 1400ma one and desolder one 7135 off and you will have 1050ma. Its your choice as to what you want the led drive current to be. They also have 1-mode 1050ma drivers no desoldering needed. They are several places that sell these AMC 7135 of boards.

 

[gcbryan]

Soldering is one area I haven't had any luck with. I do have some basic soldering equipment but I haven't had any luck.

If I decide to practice at bit more with old junk parts this is a good suggestion. I have 4 lights where I care about the throw and would like the driver upgraded on all of them.

All are single mode using either 18650 or 14500.