First mod attempt... what batteries to use?

Hi,

Very, very new to this flash-a-holic thing, but have an idea I want to try out, more for a learning curve than anything else.

I've just had one of those made in china/korea 2 for a £1 keychain lights die on me and threw it away in the bin. Then i had a thought.

So, I rummaged through the bin (and an old quarter punder with cheese, urgh!) and got it back and took it to pieces to get at the led.

Now, this led was a "white" led and powered by two 3v coin batteries and what I wanted to try is:

Put the led into a minimag (either a 2xAA or a 2xAAA) with a drilled-out reflector I have from a Lamba kit I recently recieved.

The problem I have is finding batteries that are 3v and will fit into either a 2xAA or 2xAAA minimag.

I read here recently about someone using a Duracell battery (I think it was called something like a CRV-3 — please excuse my ignorance) which used 2 seperate 3v batteries which can be pulled apart and used.

So, would these batteries fit into either a 2xAA or 2xAAA minimag. Not too worried about having to find a spacer or "padding" to stop rattling — like I said it's my first ever "modding" experience (if I even dare call it that /ubbthreads/images/graemlins/smile.gif ) and just would like to see if it works.

I hope you can understand where I'm coming from and what I hope to achieve and are able to offer some advice.

Many thanks,

Face

/ubbthreads/images/graemlins/thinking.gif CR2 batteries are 3V but fatter than AA.

"I read here recently about someone using a Duracell battery (I think it was called something like a CRV-3 — please excuse my ignorance) which used 2 seperate 3v batteries which can be pulled apart and used."

Yup, that's what you wanna do. However, was the LED attached to a circuit? 6V seems a bit high for a regular LED and you might fry it, I think white LED's have a Vf much lower than that. Try 2xAA first and see if it's too dim/bright, whatever. Better dim for starters than killing the LED.

To answer your question about whether they would fit: yes, when you take apart the CRV-3, you will have two cells that are AA size. In the CRV-3 I took apart, each cell was 3 volts, and the two cells were wired in parallel. However, I have read somewhere that some of the CRV-3s use 1.5 volt cells that are connected in series, so you might want to measure the voltage just so you know what you're dealing with.

Have fun with your mod!

Tim

Also, if memort serves, the part of the cell from the crv-3 pack that looke like (-) is plus. At 3v it wount harm the led, but you may have to flip it around to get it to work. The reason the small fob's can get away with putting 6v on a white LED is that the 2 'watch' batteries can't put out enough current to damage (severly) the LED. On the same note, of you put 6v worth of crv-3 batteries in there, IT WILL GO POP, and probably stink too /ubbthreads/images/graemlins/icon15.gif . some of the newer white and even some of the older ones have a lower then normal(3.60v) running voltage. first just try using 2 alky batteries, or you could pick up some Lithium energisers (+/- $10 for a 4 pak). keep in mind that the cost for the lithiums are weighted against the fact that they will last for a LONG time in this configuration.
Jeff

GreenLED

No, there was no circuit. Just two 3V coin batteries and the LED. When you squeezed the case it made the LED "legs" come into contact with the batteries.

I tried the led on just 1 x 3v coin and it hardly lit up at all.

Again, excuse my ignorance, but what's the difference between having batteries in parallel and in series? Please go easy on me /ubbthreads/images/graemlins/smile.gif

Many thanks for the advice so far,

Face

parallel means (+) to (+) and (-) to (-), this would keep the voltage the same but doubble the capacity of the battery. Series is (+) to (-), this increases the voltage.
Jeff
Also, 3v coin cells are useually pretty clost to 3.0v. New alky's are useually a tad over 1.6 (fresh) and Lithium's are 1.7v to 1.8v(fresh). soooo.. 2 alky could provide 3.2-3.3v and Lithium's 3.4-3.5v.. more then enought to decientally drive a white LED, better than a single coin cell anyways.