Flashlight driver

Hi all,
a few days ago in the Sunday "Porta Portese" fair in Roma I've bought for 13€ this flashlight with zoom:
http://i47.tinypic.com/do9ybm.jpg
with a 18650 battery (a blue one; the one in the picture is salvaged from an old battery pack), 220V charger (very simple, but exactly 4.20V) and 12V charger.

It works well, but the driver is impractical: Hi (1A), low (200mA), strobe. I haven't understood if it has a memory. If I wait for 2 minutes or more, sometime i find the same last mode; if I switch on after a few seconds or only a minute it starts with the next mode.

I've bought a 5-mode with memory driver PCB from Hong Kong, but the seller told me there are quality problems, then I have to wait some weeks. Furthermore, it is 17mm diameter instead the 20mm original PCB, then I have to fit it making an adapter.

Does anyone have any idea?

Thank you!
Gianluca


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For a high quality, efficient, no nonsense driver look at shinningbeam & the '3-mode perfect regulated board'; it's made for your battery type, (also works with 3X Nimh) 3 modes with memory; 1A, 350mA, 60mA. no strobe, on blinky modes. He has a couple others that may suit your project as well. They are 17mm also so you will need to shim.

I like simple, reliable and efficient in a driver. Maybe out of trendy style but I also like and use the drivers at 'the sandwich shoppe'. Good luck.

Thank you, LowLumen.
It's very interesting, altough it costs about 17$ (14€) shipping included, more than I paid for my flashlight...
I'm thinking to make a switching current-regulated supply, using a MC34063, inverting configuration. Problems are: -space -a suitable small coil -no memory: I have to use a trimmer or a potentiometer/switch.

Gianluca

http://i50.tinypic.com/2z5ui2p.jpg
Ooops... Output capacitor polarity is wrong!


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You not really are thinking of BUILDING Your own driver and
A) get cheaper and
B) smaller
than a purchaseable driver solution, are You?



PS: yes, any driver - even crap and unreliable ones - will be more expensive than that light.
What does this tell You about the "quality" of the light?


PPS: get a better light,
and stay away from unprotected batteries!

yellow said:

You not really are thinking of BUILDING Your own driver and (...)

Click to expand...

I have already built many buck and boost switching regulators, up to 4A. Major difficulties are to get the right transistors (fast, low Vcesat, high gain), coils (100~200uH) and diodes (Schottky). I salvage and keep many components from broken switching regulators

I'm thinking to try something like a CD4017 to start with a preset intensity everytime I power on, then switch to other levels with short pulses

yellow said:

PS: yes, any driver - even crap and unreliable ones - will be more expensive than that light.
What does this tell You about the "quality" of the light?

Click to expand...

Light is very flat and strong. I like it.

I have already built many buck and boost switching regulators,

Click to expand...

I also have and of course I know the problems (the ones You mention and all the others, too)
but You did not requote the main points:
1: How do You think to get the homemande driver into a light offering that little space?
2: When that BIG, homemade driver will be more expensive than the cost of a cheap driver (together with its shipping costs) ... why doing that?



PS: That light is not done good - mechanically, surface, parts used - when putting such efford and time into a project, better get one where it makes sense to mod it. Where the parts are machined well and from material + threatment good engouth to live longer than a few hours of use

yellow said:

1: How do You think to get the homemande driver into a light offering that little space?

Click to expand...

The spring is very long. Using SMD's there should be enough space.

2: When that BIG, homemade driver will be more expensive than the cost of a cheap driver (together with its shipping costs) ... why doing that?

Click to expand...

Shipping from USA to Italy requires very long time and I'll have to pay customs (if the parcel will arrive at my home...).
I build my projects using salvaged devices. I have a very large quantity of them. Many of them are very fine, from broadcast equipment.

PS: That light is not done good - mechanically, surface, parts used -

Click to expand...

Mechanics are done very well, with also many o-rings (though I'll not use it in critical conditions)

I'm trying to understand how works the memory of the original driver. It seems to work well, but time allowed to change mode is very long. If I'll build my driver I'll try a CD4017 with a schottky or germanium diode and a capacitor on Vdd to hold the state for a few seconds. If I power off for more time it will go back to preset intensity. I can choose reference resistors values i.e. to have the sequence: 20%, 50%, 100% or another, like 50%, 20%, 100%.

LowLumen said:

For a high quality, efficient, no nonsense driver look at shinningbeam & the '3-mode perfect regulated board'.

Click to expand...

Uhmm... It says:
* Voltage input: 2.8V - 5.5V
* Low and medium mode are current controlled, not PWM
* Perfect regulated circuit for constant current output
It seems "High" is not current regulated, like using a simple buck switching regulator... A buck/boost or SEPIC or inverting configuration will provide current regulation also at the maximum current and a partially discharged cell.

Datman said:

.....................
* Perfect regulated circuit for constant current output
It seems "High" is not current regulated, .........

Click to expand...

High is current regulated to 1A on that board.

That driver is also 16mm, not 17mm.

My original driver is 20mm. It needs an adapter anyway.