PD flicker

[tibim]

I seem to remember hear somewhere that this is normal but wanted to run it by other PD users. Anyone experience the light flickering when the battery gets low? This is normal for the converter? The weird thing is I can give the light a hard tap with my finger or beat it on the table and it will make the flickering more frequent. It will not flicker as much when just sitting on the table untouched. I am running this light in high mode. Does not do this with a new battery so I'm not sure if there is some kind of a contact issue or not.

The light I have is a PD-S mizer.

-tibim

 

[Codeman]

Yes, this is quite normal for most regulated lights. If it ever does flicker with a new battery, then that would possibly indicate a bad or dirty contact.

 

[McGizmo]

I am no electronics expert by any stretch of the imagination but I would guess that your "fiddling" with the light at this point may be increasing or decreasing the resistance in the contacts enough that the converter tips into or out of regulation when the battery is at its limit.:shrug:

 

[tibim]

Upon further testing...

At what point of battery exhaustion is this flickering considered normal? I changed the battery in the PD with one that was not brand new but still had quite of bit of juice left in it. The PD was running nice and bright in high mode. After allowing it to run for about 45 minutes I noticed the flickering beginning again. The light was still running very bright(to my eyes it didn't seem much more dim, if at all, than with a full battery) but the flickering was occuring none the less. It wasn't as drastic as the flickering with the very weak battery that I previously experienced, but was still interrupting the otherwise high output. Tapping the light in this case did not make it flicker more.

What's normal?
Should the PD get noticably dimmer before the converter begins this flickering? Or is this phenonmenon the converter being unable to hold high regulation and changing between high and a lower mode?

My next test will be to take a known 100% CR123A and start it running, keeping an eye on it to see when it beings to flicker.


-tibim

 

[McGizmo]

I am not sure I can answer this properly. The wiz2x2 is a buck boost converter so as long as thebattery can provide the required power, you will have constant current to the LED which means no noticible dimming of the light. At the point that the battery can no longer provide the required power, the converter starts acting up with flickering. I take this as a sign that it's time for a new battery. The extent of flickering is not consistent from unit to unit that I am aware of but then I have not done any testing of a number of these at the point where it is time for a new battery. :shrug:

Perhaps others can chime in with their experience here. I do know that the flickering issue was more pronouncd with higher current settings and this is one of the reasons that I did not mess with turbo levels. With the mizer drive level, it is likely that the converter is milking more power out of the cell and when it is at the point of marginal capacity, it is really at the point of marginal capacity!! The Mizer is a new deal here so you are part of the experiment!!

 

[Illum]

erm....

personally, my PD never flicked until the last minutes where the battery died...

 

[Roccomo]

+1 for what illum the nation said...lux PD.

 

[tibim]

erm....

personally, my PD never flicked until the last minutes where the battery died...

Interesting..
Can anyone with a PD-S (preferably mizer like mine) give us some input?

The voltage of the cell that was causing it to flicker right now is 2.73 volts. This is pretty darn low. The almost dead one I was playing with yesterday was at 2.70 volts. So the battery in there now is much more dead than I thought it was.

I think you are right Don... The mizer version, being that it requires less juice, is better at staying in regulation until the battery is close to exhausted. It has a slower "death" or longer period of flickering than a non-mizer.

I don't think there is any kind of a contact problem or any other issue with the light. It is interesting to see how the mizer version is different from the standard when it comes to low battery.

I have put the weak battery from last night back in(2.73v) and continued running it. It has been going about twenty minutes now and gone from flickering every few seconds with high light output to a lower(medium?) level of light with a more frequent flicker. The flickering now is probably a constant 10hz, but the output remains constant(it is however slowly getting dimmer). Reminds me of a PWM light right now. Constant light level but noticable flickering. Keep in mind the light is in high mode and the flickering of course goes away if I switch it down to low.

-tibim

 

[Kiessling]

Flickering with dying batteries is normal. A big big variation with the amount and time of the flickering is also normal, even with the same light and different batteries.
No need to worry, I see it as the last-ditch battery indicator.
bernie

 

[tibim]

No worry anymore.

Just collecting information

-tibim

 

[blahblahblah]

This past Sunday, we used my Ti PD for BBQing illumination in 20 degree weather. When the battery ran out of juice it just switched off. I was using an RCR123a so this could have been the protection circuit.

 

[NewBie]

I often use flashlights in my lab, as I will turn off ambient lighting to reduce the effects of stray light.

While I was testing a new version of a photodiode fast light measurement circuit, I happened to shine my PD at the photodiode, and lone an behold, I saw pulses in the light. I thought thats interesting, wondering what was wrong with it. The pulsing was probably about 250KHz, and a 20% off-duty cycle.

The following week I replaced the cell, as I was taking it somewhere where I needed it for certain.

While I was checking the photodiode's circuit interaction with another circuit, and checking out that circuit, I noticed the pulsing was gone, with the new cell.

This one has the Wiz 2x2 circuit in it.

 

[Illum]

I am no electronics expert by any stretch of the imagination ...

EDITED [reason: personal stupidity]

 

[farmall]

*

 

[Kiessling]

dat2zip designs the drivers / electronics in Don's lights. It is the guy of the Sandwich Shoppe.
bernie

 

[Illum]

edited, thanks for the clear up