Petrov45 MkII

G'day Everyone

It's likely none of you will remember my early attempt at building a 35W HID spotlight...

That's for the best, because it was crude, and mostly held together with race tape.


I've made a few changes and would like to share them!

Firstly, I've managed to fit the ballast inside the body of the light, returning the Arlec RT3500 to it's regular svelte self. Then I had to work out what to do with the dirty great big hole I'd cut in the body to allow for the cables to pass...

I decided on a DC socket!

(Please exuse my poor manufacturing abilities, and the fact I managed to smear glue over most of the body in the process)

This socket is wired in to the 12V input to the ballast, but AFTER the switch for the batteries. This means I can run the light from any 9-16V power source that can supply sufficient Amps, and that I can make plug into the socket.

The first cable I've built for it simply has two alligator clips on it, allowing me to attach the light directly to a car battery, or similar.

My second option was to raid the box of old AC Adapters at work (I work for a computer repair business - plenty of old laptop chargers). I came across this old Toshiba pack, designed for the old "Desktop replacement" style laptops. This thing has to be able to supply some juice!


As it turns out, 15V at 6Amps is heaps, and it powers on the light with no hassles, and has quite happily kept it running for an hour, without the pack getting any hotter that it would have while charging the laptop it came from.

So now, my little 35W experiment happily hums along at 45 Bulb Watts (I wish someone could guess how many lumens that might be), gets 30 mins from a battery charge, can run off of any 9-16V power source that I can attach alligator clips to, and can run directly from mains power for as long as I want!

Now all it needs is some cosmetic fixes, and I'd call it a success!

(In case anyone was wondering, It's called Petrov45 after Vasily Petrov, the nice Russian man that kindly discovered the electric arc effect, making this all possible. The 45 bit is kinda obvious)

And one last pic, testing how far the exposure compensation on my camera could go!

I remember your light. Nice to see that you're back at it again.

The DC plug from the toshiba pack still feeds the ballast correct? I'm just trying to understand what changed to make it 45W.

Thanks.

Patriot said:

I remember your light. Nice to see that you're back at it again.

The DC plug from the toshiba pack still feeds the ballast correct? I'm just trying to understand what changed to make it 45W.

Thanks.

Click to expand...

It's 45W thanks to pot-modding the ballast.

The toshiba pack is feeding directly into the ballast input, yes.

Oh, very cool. I missed any discussion about pot modding.

You're probably close to around 4200 bulb lumens give or take 10%.

Patriot said:

Oh, very cool. I missed any discussion about pot modding.

You're probably close to around 4200 bulb lumens give or take 10%.

Click to expand...

I was guessing ~4000 lumens conservatively, so that makes me happy!

Very nice work! It must be an amazing thrower. I saw your older beamshots of it and I could tell it has a very tight, well formed beam.

I agree with Patriot; 4000 lumens or a little more would be about right.

Being where I am geographically, I have the advantage of being able to get out of town and be in perfect dark in about 5 mins.

There's a perfectly straight road nearby ending at a T intersection. At the intersection there's a red, reflective street sign.

I drive to the intersection, turned around and drove back up the straight road after resetting the trip counter in the car.

As it turns out, I could still clearly see a bright, red dot (too far for the camera, so no photos, sorry) at 1800m.

Now I realise thats not a true indication of throw, thanks to the reflective nature of the roadsign, but I find it impressive nonetheless!