runtime question on direct driven DX 3AA X2000

[barnefko]

Hi Folks

I recently bought a x2000 torch from DX (see http://www.dealextreme.com/details.dx/sku.14228
Because i wanted to use it as a headlamp i drilled a hole in it, soldered two wires and connected a 3AA batterypack so i can wear the batteries in my pocket (-20C here in sweden...)

Ok, long story short: sadly its a direct driven light and i couldn`t find any runtime graph for a direct driven SSCP4 light on 3 serial AA`s (2000mah Eneloops in my case). For my trips with the bike and my ski-tours i would need a runtime graph or esimation, so i know when i have to pack 3 extra AA`s

Thank you so very much for your help and sorry if this was mentioned before, but i couldn`t find anything in the forums.

Greetz from the darkness. :candle:

 

[Barbarin]

Use the force of the "search", Luke.

I don't remenber who or when, but runtime graphs regarding this have been posted many times, and you can even use the LED calculator, (but you are going to need the current draw) CALCULATOR


You have posted the link to the CR123 battery type light, but I think you wanted to talk about the 3AAA. Well, in that small light I would not use more than 400 mA/hour (again you need a tester), and that taking care of the heat dissipation of the star. (Many cheap lights just use "air" as conductive interface. :shakehead

At 400 mA on T=0 min using NiMH DD resistored down you can expect to reach T= 420 min @ 250 mA, before the line gets down faster.

Probably if you battery holder and wire have enough resistance you are not going to need any resistor.

Hope it helps.

Javier

http://www.kenworster.com/ledcalc/

 

[barnefko]

Hi
Thank you very much, i somehow wasn`t able to find the calculator you named above.

Small correction: i converted the CR123 light into an 3 AA (R6) light. I took the CR123 version because of its size.

Please note that this mode is done at a very low level of experience and skill. I didn`t use any resistor, just connected the P4 star directly to the 3 AA`s.
Not a good idea? At least it seems to work for now......

Thank you for your patience.....

 

[Barbarin]

Hi
Thank you very much, i somehow wasn`t able to find the calculator you named above.

Small correction: i converted the CR123 light into an 3 AA (R6) light. I took the CR123 version because of its size.

Please note that this mode is done at a very low level of experience and skill. I didn`t use any resistor, just connected the P4 star directly to the 3 AA`s.
Not a good idea? At least it seems to work for now......

Thank you for your patience.....

If you are wiring the batt pack to the driver I'm not sure because I don't know the driver (it could be a step-up, step-down, buck-boost...). If you are wiring directly the batt pack to the LED you are probabaly about to damage it unless your wire and batt pack has enough resistance or the LED very high Vf.

In order to make decent mods you need some knowledge of basic (very basic) electronics. Here you can find very usefull information that was posted some time ago on CPF. You will need also a multimeter, and that won't cost you more than 15 €.

It is very important to measure current through the LED, as it is easy to fry it when wiring directly to the batteries, and even more if the thermal dissipation is not good enough. Time ago I posted something very basic about that, "Thermal management optimization"

If you spend a while here on CPF you will be able to make amazing mods, a lot of them much better than regular production flashlights. Homemade and moddified lights are not created as industrial products which have very restrictive aspects, and that allows modders to make great products.

Regards, and good luck with your mods.

Javier