12v DC to 1.2v DC

Thread Starter

Scotty762

Joined Oct 23, 2015
8
Hi anyone,
I have a spare torch I never use I want to mod , Led Lenser L7, want it to run full time from 12v.
It normally runs off 3 x AAA 900mAh NiMH 1.2V batties.
Does anyone have a diagram on how i could do it? I dont have alot of knowledge on electronics.

It'd be cool to have the circuits in the torch barrel 20mm Dia x 60mm .

The reason is, I need to have max performance all the time. Distance = production when night shooting. This torch just runs 4 hrs or so then its not enough to be worth carrying anymore.

Any help Appreciated , Scott
 

GS3

Joined Sep 21, 2007
408
Where are the 12 V coming from? Because it seems to me carrying an extra set of batteries is easier than anything else you can do.

Also, some, many, LED flashlights rely on the battery's internal resistance to limit current. If you supply too much current you can fry the LEDs.
 

Dodgydave

Joined Jun 22, 2012
8,471
How is the torch going to be used, in the hand or on a tripod/ holder, how big is the 12V battery, you are still going to have to charge the 12V battery, surely it must be easier to take an extra set of nicads with you?
 

mcgyvr

Joined Oct 15, 2009
5,394
If the 3 batteries are in series you would need a to make/buy a 3.6V supply not 1.2v..
If the current limiting is built into the flashlight a 3.6V constant voltage supply is all thats needed.
 

Thread Starter

Scotty762

Joined Oct 23, 2015
8
Torch will be in hand or mounted on rifle scope. will run from sockets in 4x4 or boat .
I understand theres tonnes of alternatives. I have heaps of spare batteries and a few other torches to use but want to make this for fun. Thats why i chose the cheaper plastic L7 not p7 or p7.2 .

Im already drawing up a new endcap to hold a button and a 2.1x5.5 female plug.

Will the needed circuits fit inside the torch tube? anyone have any diagrams?

Chers,Scott
 

Thread Starter

Scotty762

Joined Oct 23, 2015
8
Yeah sorry , i had a reply open for hours before i clicked post.

I believe the batteries are in series . Here is a link with someone that pulled a similar torch apart maybe you can understand what kind of regulations it has: http://budgetlightforum.com/node/34815

Dodgydave , i had a quick look , Lm2596 chip looks ideal ! size and everything! now just to find it in NZ
 
Last edited:

ian field

Joined Oct 27, 2012
6,539
Where are the 12 V coming from? Because it seems to me carrying an extra set of batteries is easier than anything else you can do.

Also, some, many, LED flashlights rely on the battery's internal resistance to limit current. If you supply too much current you can fry the LEDs.
A 3 cell unit is almost certainly as you describe.
A 2 cell type has insufficient voltage for a white LED, and pretty certainly has some form of built in voltage booster. Making a selection on that basis would be the best solution to the TS's problem.
 

Thread Starter

Scotty762

Joined Oct 23, 2015
8
Since Im(we) are modifying it, what would be the best cree and driver for maximum throw? with or without the buck converter. Truck is 12v ish , 50amp alternator.

Something like 1m dia beam at 500m would be fine for example. Just one mode is fine too.

All inside the L7 or P7 shell. I think the original driver is under 20mm Dia.

Am i dreaming here?
 
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