low-level Lumens Factory D26 dropin

[325addict]

I think, this is the best place to announce, that I started a feeler on CPF Marketplace for some special production run low level incan dropins by Lumens Factory. After a very good talk with Mark from Lumens Factory, we came to the conclusion that it might be very interesting indeed to start a limited production run of low-level D26 incan dropins. Technical specs are:

design voltage: 8.0V (meant to be run from 2X Li-ion 3,7V)
current draw: 300mA
type: ultra high pressure Xenon lamp
life: at least 50 hours(!)
Lumens: 50
unfrosted version (most people seem to like this best).

The run will be once, and will give a batch of 30 to 50 lamps, depending on how many good ones come out. Remember, these lamps are not available from Lumens Factory, and will be made only once....

Here's the link to the thread:

http://www.cpfmarketplace.com/mp/showthread.php?p=2298196#post2298196


Timmo.

 

[Blindasabat]

These will be excellent "nightly dog walk" lamps. Nice specs for real world non 'tactical' use.

 

[cernobila]

How about using the LF ES-9 rated at 850mAh and installing the AW soft start/three level switch, on low this would be rated at about 285mAh. Not sure about the colour temperature at the low setting or the life of the bulb.

 

[325addict]

@ Cernobila: unfortunately, the efficiency of any incan bulb is rapidly going down when underdriven.

This means, a 5W bulb that is driven on, for instance, a power of 2W is by no means comparable with a bulb, which has a power of 2W by design. It wouldn't surprise me at all, if the dimmed 5W setup only has 10 Lumens, instead of the 50 Lumens you will have with this low-level bulb running on its full voltage.
This is a 2.4W bulb, and will perform well. The color temperature of an underdriven bulb is very, very low. The light will be really orange!


Timmo.

 

[DM51]

There is another factor to take into account when deliberately under-driving incan bulbs.

Using any bulb at well below its rated power (by reduced voltage, or PWM - it doesn't matter which) will eventually result in a white smoky deposit on the inside of the bulb envelope.

This smoky deposit results in reduced effective output, in the same way that a very dirty window transmits light poorly. The more the bulb is used like this, the more noticeable the effect becomes, until eventually the output is severely affected.

 

[325addict]

@ DM51: is this also the reason, why you shouldn't dim halogen bulbs? Time after time, I read warnings on this. My brother however, lacks the technological understanding, and is quite stubborn in this, and dimmed his mains-voltage halogen bulbs and.... even after YEARS of constant (dimmed!) use, the first one still has to fail on him yet.....

:thinking:

Timmo.

 

[Bullzeyebill]

I am using AW's soft start 3 level SF C series switch, and yes there is more yellow noted on lowest level, but not too bad. AW's switch uses PWM and the bulb is always delivered the bulbs rated A's at all levels, but the frequency of on off switching causes the light to appear dimmer. JS did a study of this awhile back using the dimmer switch for the Streamlight SL20. The filament does not cool down long enough to affect the halogen cycle. The filament is always getting the full rated amperage but in short fast bursts.

Bill

 

[DM51]

@ 325: Yes, that is the reason why dimming halogen bulbs is not recommended. You can do it, and in fact it is a feature on some incan lights, but it is not recommended for extended use. It won't cause the bulb to fail or blow, as it is being under-driven; it is just that you get this white smoky deposit on the inside of the glass. Eventually it obscures the glass, diminishing the amount of light that can get out. The glass also then becomes the light source, instead of the filament, and being a larger light source it results in a more diffuse, floody beam, in addition to it being dimmer.

@ Bill: PWM will not help or solve this. Yes, the current is flowing through the filament in bursts at the correct rate, with the correct voltage being applied, but what is actually happening is that the filament is operating on an average of the current, as it cannot heat up and cool down instantaneously in the same way a LED can. Instead of the square wave of light emitted that you would see with a LED, you would see the wave pattern had in fact been completely flattened out to an average. That's why you see a yellower color at the lower levels. It isn't drastically bad for the bulb, but if used for extended periods you will eventually notice the white deposit begin to appear.

 

[cernobila]

I am using AW's soft start 3 level SF C series switch, and yes there is more yellow noted on lowest level, but not too bad. AW's switch uses PWM and the bulb is always delivered the bulbs rated A's at all levels, but the frequency of on off switching causes the light to appear dimmer. JS did a study of this awhile back using the dimmer switch for the Streamlight SL20. The filament does not cool down long enough to affect the halogen cycle. The filament is always getting the full rated amperage but in short fast bursts.

Bill

So, if you get full amperage in short bursts, what is the effect on run time if you use any bulb on low only as compared to high only.

 

[Bullzeyebill]

So, if you get full amperage in short bursts, what is the effect on run time if you use any bulb on low only as compared to high only.

Less amperage from battery over time, so runtime will be longer. Many of our Led lights use PWM in combination with constant current for dimming. PWM provides the dimming, with subsequent longer runtimes.

Bill