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chrisgerman1983 03-17-2014 05:21 PM

Camera Flash mod?
 
This is not eco modding related at all but you guys are pretty damn smart so I figured you would know the answer. I have a camera flash that I want to apply more voltage to, to decrease the recycle time. How much extra voltage can you usually give a device before damaging it? The flash uses 4-AA batteries and I want to somehow use my 18v Lithium ion battery pack for my cordless tools ( I have way more then I need) From what I have read there are battery packs for these flashes that give 300v and the biggest concen isthat you can pop the flash so fast it will melt. Any ideas?

EcoReality 03-17-2014 07:10 PM

If you know what you're doing, you can go in and charge the HV cap directly.

A typical flash has a high-voltage capacitor -- 300 to 450 volts or more -- and a circuit that boosts battery voltage to cap voltage in order to charge it.

Very expensive flashes have a way of applying 300+ volts directly to the cap (well, through a current-limiting resistor, to keep from frying things). This allows the minimum possible recharge time.

If you <i>don't</i> know what you're doing, I advise against this! There is potentially lethal voltage there!

Cobb 03-17-2014 09:09 PM

I dont think you can go from 6 volts to 18. Maybe 7.5 with an extra cell. You will generate too much heat too fast and melt something.

P-hack 03-17-2014 09:39 PM

12v pack -> inverter -> strobe light :) you will have to sort out the trigger, but the power circuits and recharge times are all there.

chrisgerman1983 03-17-2014 10:06 PM

hmm getting it to sync to 1/200th of a second could be tricky :D

D.O.G. 03-18-2014 02:16 AM

If you're wanting to use the 18V battery pack, maybe you could drop the voltage with something like this.
LM2596 LED Voltage Regulator DC Buck Adjustable Step Down Converter Module NEW | eBay

I'd be wary about raising any rated voltage more than 25% without knowing what components the manufacturer has used in the first place.

chrisgerman1983 03-18-2014 02:01 PM

that would be perfect and i could dial the voltage up a bit at a time too. If I posted a photo of the components would you be able to give more insight?

D.O.G. 03-18-2014 06:20 PM

Quote:

Originally Posted by chrisgerman1983 (Post 415887)
that would be perfect and i could dial the voltage up a bit at a time too. If I posted a photo of the components would you be able to give more insight?

I'm willing to try, but I expect it would be hard to tell from a photo.:o

Thinking about this some more, as much depends on the duty cycle of the flash unit as the charge time/voltage.
At the end of the day, it's up to you how far you want to push the envelope. How expensive is this flash unit and can you afford to accidentally cook it?

In regard to P-hack's comment about strobes, I've seen slaved strobe units used in a photographic studio.
These were self contained, mains voltage units that were triggered by the flash of the camera. I can't give you any details though, I only worked there briefly, many years ago.

nemo 03-18-2014 07:09 PM

Yes flashes can be over heated if they don't have thermal protection. Below some recycle times based on battery chemistry and number of batteries.
SB-800
Number of batteries
Min recycle time
Alkaline-manganese
x4
6.0 sec.
x5
5.0 sec.
Lithium
x4
7.5 sec.
x5
7.5 sec.
Nickel
x4
6.0 sec.
x5
5.0 sec.
NiCd
(1000 mAh)(rechargeable)
x4
4.0 sec.
x5
3.5 sec.
Ni-MH(2000 mA)(rechargeable)
x4
4.0 sec.
x5
2.9 sec.
Fresh Batteries

As you maybe aware firing the flash at less than full power also increases recycle time. Can you just move closer. What type of recycle time are you looking for.

Cobb 03-19-2014 06:11 PM

What exactly are you trying to do? Are you trying to make it a strobe light or take photos faster with a camera?

You can get cheap led strobe lights around halloween time.

For cameras you can also get better flashes. I have 2 for my 35mm camera alone with some lenses that are a few feet in length. I got one flash that is smaller in size and can shot off like a strobe light. I can zip through a roll of 35 mm film in a manner of seconds. If its night I got an ir feature too. The other flash is about as big as the camera and is freaking bright. It doesnt cycle as fast, but its bright and worked well for even outdoor pics in total darkness.

EcoReality 03-19-2014 07:50 PM

You can get into the pack and charge the high-voltage cap directly from rectified line voltage.

KIDS! DON'T TRY THIS AT HOME!

I don't think you want to raise the battery pack voltage. It's designed for 6V, and going much over that is likely to fry it. Instead, go in and charge the cap directly with 300V or whatever. Take the voltage off the cap label, and go 25% or so below that, and put that much into it.

chrisgerman1983 03-20-2014 04:14 PM

Thanks for the replies. I am trying to get faster recycle time for the flash. I want to fire at full power in bursts but not for too long. It is an older flash I wouldn't be heartbroken if it fried but I want to try and avoid that from happening. I can buy newer faster flashes or full studio strobes but I like to use what I have if I can. Here are few pictures of the insides.

http://i58.tinypic.com/23mlvue.jpg

http://i59.tinypic.com/1zq6lfp.jpg

http://i60.tinypic.com/nmceh3.jpg

EcoReality 03-22-2014 07:07 PM

That big cap in the second photo -- charge it up and measure the voltage on it. Then jack that voltage into it for the absolutely fastest charge. Unless there's a bigger cap the photos don't show. (The main charge cap generally takes up a good 50% of the space.)

chrisgerman1983 03-23-2014 08:15 PM

Thank you! I will take it apart a little more. I thought it seemed small, The disposable cameras i have taken apart had way bigger.

chrisgerman1983 03-29-2014 01:58 PM

Ok here is the big guy, 350v. So how should I wire the battery into the cap? is it just as simple as running + & - or does the cap run in line to the flash.

http://i57.tinypic.com/zu1b13.jpg

EcoReality 03-29-2014 06:26 PM

Quote:

Originally Posted by chrisgerman1983 (Post 417734)
Ok here is the big guy, 350v. So how should I wire the battery into the cap? is it just as simple as running + & - or does the cap run in line to the flash.http://i57.tinypic.com/zu1b13.jpg

Okay, now you've got a bit of engineering to do.

You need a ~340 volt supply. Do not exceed 350 volts, or you'll fry the cap! Apply it to the cap. That's about it. Note that if you use a commercial power supply, it may also have big caps hanging on it, and combined with the one in the flash, may supply enough energy to fry the flash tube.

If your 340 V supply is "stiff," (low output impedance) it might be good to limit inrush current to the cap with a small resistor. I can't tell you what to use without knowing more about the HV supply.

Basically, the rest of the electronics is an inverter to get the 6 V from the batteries up to 340 volts, plus a trigger transformer that gives a very brief pulse of some 10,000 volts to cause the cap to discharge into the tube.

Be careful. There may be enough energy in that cap to cause all your friends and relatives to gather in your honour.

chrisgerman1983 03-29-2014 06:59 PM

ookaayy... I might put it back together lol... thank you very much for your help!

Cobb 03-29-2014 07:28 PM

Were you just going to solder some leads from a double a battery or the one from your power tool?

Quote:

Originally Posted by chrisgerman1983 (Post 417795)
ookaayy... I might put it back together lol... thank you very much for your help!


chrisgerman1983 03-29-2014 07:30 PM

I think I would have had to run the higher voltage directly to the big cap?

Cobb 03-29-2014 10:00 PM

Yes, those tubes take a bit of voltage to light up. Now led strobe lights do not need that high voltage.

HIGH VOLTAGE ROCK N ROLL!!!!!:thumbup:

EcoReality 03-30-2014 12:38 AM

Quote:

Originally Posted by chrisgerman1983 (Post 417805)
I think I would have had to run the higher voltage directly to the big cap?

Yes, but there's no way to run 18V into anywhere on that flash and get the result you expect.

The existing inverter is designed for 6V, which it then turns it into ~350V. So you'd need to build an inverter to turn 18V into ~350V.

Or just connect a rectifier to your 240 VAC clothes dryer plug and run that to it. You'd end up with around 340V DC.

(NO! I CAN'T BELIEVE I WROTE THAT! KIDS, DON'T TRY THIS AT HOME!)

Seriously, don't do that! And heirs, don't sue me if he does! :-)

Cobb 03-30-2014 01:03 PM

You could always visit a radio shack or an online equivalent and make a cascade voltage doubler and in no time you can get your 18 volt battery to a few hundred to few thousand.

P-hack 03-30-2014 03:25 PM

the built-in inverter on those are crap. You can do boost or even h-bridge (into a 12v wall wart) -> doubler to get to 300v. (plus you need a 4000-8000v trigger)

I'm liking the LED approach, looks like that will fire repeatedly, all day, with less losses. Will need to play with the exposure. But it looks like that is where "flash" has been headed for a while(more efficient, don't need 300+ volts, no glass parts). little xenon tubes get in trouble with overuse/overheat.

http://www.cap-xx.com/resources/docs...D_flash_v3.pdf

Edit, well, long exposure times have their caveats too.


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