Rayovac Sports Headlamp - First time mod advice

[electronics4life]

Re: Rayovac Sports Headlamp - First time mod advic

I haven't yet had my light apart so I can't be much help on your switch location. If you were doing as I am though (3 white LEDs and 1 LS). You could use the existing switch for 1 LED setting and 2 different current LS settings.

I know it kind of seems pointless doing all white. I was hoping to achieve a setup similar to what I use everyday at work. I use a Princeton Tec Attitude (3 regular LEDs) for most tasks with a long runtime and a Badboy400 Q3 only 20% of the time. Granted I don't know how much current the Attitude pushes through its LEDs. I was just guessing around 30ma. To be honest the whole headlamp is kind of pointless to me. It might get used once a year while camping. BUT, the fun of learning and designing is worth it to me as my major is Electronics Engineering.

 

[electronics4life]

Re: Rayovac Sports Headlamp - First time mod advic

Forgot to ask. What current is most LS ran at? I think I read 350ma. What "hotter" transistor are you going to use for your LS?

 

[electronics4life]

Re: Rayovac Sports Headlamp - First time mod advic

Still wondering..

 

[jtice]

Re: Rayovac Sports Headlamp - First time mod advic

350mA is spec...
but you can push over 750mA, IF you heat sink it really really well.

 

[electronics4life]

Re: Rayovac Sports Headlamp - First time mod advic

Well I won't be heat sinking it at all /ubbthreads/images/graemlins/ooo.gif. Unless the star backing counts. /ubbthreads/images/graemlins/tongue.gif Needless to say I will only be pushing 350ma through it.

 

[Doug Owen]

Re: Rayovac Sports Headlamp - First time mod advic

[ QUOTE ]
electronics4life said:
Still wondering..

[/ QUOTE ]

Sorry, I missed it.

As you already know, 350 mA is spec for them. I suspect I'll go for something about half that (plenty bright, even if a bit hard on battery life), say 160 mA then two lower levels, typically I've been using 'two f stops' (quarter current) so 40 and 10 mA.

Then maybe swap out the white LED for the 120 by 140 degree Nichias (a underused part, IMO).

When you look into this you'll see that the switch is not compatable with what you suggest unless you build two current regulators for the LS. I think a small switch to control the LS is the call.

You can push the 2N3906 to 100 maybe 120 mA before you start having saturation problems. For this use, I'll no doubt go to one of the Zetex high gain, low Vsat PNPs. A buck or so, but well worth it in this use.

Doug Owen

 

[electronics4life]

Re: Rayovac Sports Headlamp - First time mod advic

Doug, do you have a manufacturer part number for the zetex transistor. I really have no clue how to pick one just by looking at specifications. Also what formula do you use for battery life? I take it nimh batteries aren't rated "per hour" like car batteries.