Multimode lights: where's the magic?

[voxluna]

Multimode lights - HI > MID > LOW ... is that action initiated in the head itself, contain a resistor to modify the light levels? (I have one that is a single brightness no matter what, even though it is supposed to be HI > LOW. I'm trying to diagnose where the problem is rather than return to Hong Kong.)

 

[StefanFS]

You need to tell which light this is if you want to get it diagnosed properly.
Stefan

 

[voxluna]

You need to tell which light this is if you want to get it diagnosed properly.

To be exact, this is the Romisen RC-E4 I referenced in an earlier post. If you look at the discussion area for that product's page, many seem to confirm what I have found: one mode, HI, all the time.

I disassembled the whole shebang, but nothing overt stood out. I must say, I was a bit disappointed in the built quality around the emitter:

​

 

[StefanFS]

It's supposed to have a resistor of 7 Ohm in the tailcap. It doesen't, so the description is obviously wrong. With that said I recommend you to mod it with another driver, as the stock drivers of such lights often are of disastrously low quality. I've had a few different Romisen models and have modded all of them with new drivers and/or new switches. Great build quality, except that drivers and switches were bad on my lights.
Stefan

 

[voxluna]

It's supposed to have a resistor of 7 Ohm in the tailcap. It doesen't, so the description is obviously wrong.

Yes, I read this about the resistor somewhere else, can't recall right now. It seems to have happened with several buyers now.

With that said I recommend you to mod it with another driver, as the stock drivers of such lights often are of disastrously low quality. I've had a few different Romisen models and have modded all of them with new drivers and/or new switches.

I've read the Welcome Mat, twice, but the definition of "driver" is not there. Based on my limited understanding, the driver seems to be a separate part from the emitter, the one which regulates output. I don't see how they come apart on this model, though.

I did a cursory search on CPF for "replace driver" etc, but didn't find anything pertinent. Could someone point me to a thread that might explain where to start with driver replacement, particularly what's available and where?

Great build quality, except that drivers and switches were bad on my lights.

I fully disassembled the light, and found that it did indeed have good build quality, nice threads, o-rings where they should probably be, a nice feel overall.

 

[StefanFS]

I did a cursory search on CPF for "replace driver" etc, but didn't find anything pertinent. Could someone point me to a thread that might explain where to start with driver replacement, particularly what's available and where?

I fully disassembled the light, and found that it did indeed have good build quality, nice threads, o-rings where they should probably be, a nice feel overall.

Ok, I'm sorry. I presumed that you know everything about lights.

Here is a good guide on replacing a driver circuit in a led module like yours. It's another light but it's done exactly the same way, with the exception that you need to transfer and solder the springs to your new driver:

http://www.candlepowerforums.com/vb/showthread.php?t=176936

I used this driver, it will have really good regulation with ONE 18650 LiION cell. It will not work with 2 CR123 as it will overheat. There are lots of other good drivers out there, but this is an inexpensive one of good build quality, and also a good performer with one LiION cell.

There are two varieties of it:
16-mode driver
5-mode driver

Stefan

 

[Marduke]

Have you tried changing modes using a soft press??

 

[lctorana]

...but the definition of "driver" is not there...

A "driver" is a DC : DC converter which steps the battery voltage up or down to match that required by a LED (or bulb, I suppose!).

Physically, it is a small PCB with components on it, and it may be potted.


There are four key parameters in choosing a driver:

1. Drive current you want to run the LED at
2. The maximum output voltage at which it will produce that current
3. The maximum and minimum input (i.e. battery) supply voltage
4. The physical size and dimensions.

The advantages of a driver over driving with a resistor are:

1. output regulation
2. the ability to run a LED from less volts than an LED will take
3. (if using a higher voltage than the LED takes) greater efficiency.

Hope that helps.

 

[voxluna]

Ok, I'm sorry. I presumed that you know everything about lights.

Hopefully I'm quick start. I've had many incans -- Mini Mag, Streamlight, Ultrafire -- but I'm new to LEDs.

Here is a good guide on replacing a driver circuit in a led module like yours.

Thanks, those links should be very useful... I've decided to experiment on this one rather than return it. Though I did buy another light from DX, the RC-U4 3-mode.

BTW, 16 modes?

 

[voxluna]

Have you tried changing modes using a soft press??

Yeah, I've tried everything I could think of... on then soft-press (it's a reverse forward), soft press whle off, on-off-on (which should do it), on-wait-off-wait-on, etc. Given that recent buyers have all reported the same problem, I'm resigned to the fact it isn't a two mode after all. :sigh:

 

[voxluna]

A "driver" is a DC : DC converter which steps the battery voltage up or down to match that required by a LED (or bulb, I suppose!)....

Aha, this makes more sense now. It seems to answer what I was trying to ask in this thread, concerning an 18650 vs 2x RCR123.