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Archive 2012 · Electrical Engi question about powering speedlights
  
 
ether1
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p.1 #1 · Electrical Engi question about powering speedlights


So...this may seem weird at first but bear with me....
Some of us here use only speedlights...so even when you are indoors and have AC power, you still need to use batteries or battery packs.

How come nobody thought about building a little AC/DC adapter that would be capable of powering speedlights?
I can't imagine that being more than $20 in parts...the only problem, I guess, would be to ensure you don't allow the flash to fire too fast and cause it to overheat or just blow up.

I do have a friend who is a good electrical engineer and works with power controls etc... I think I will ask him to build me one and see what happens.




Nov 21, 2012 at 05:28 PM
howardm4
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p.1 #2 · Electrical Engi question about powering speedlights


this is probably horrifically overpriced but ................

http://qtm.com/index.php/products/2012-05-17-18-18-59/turbos/turbo-ac



Nov 21, 2012 at 07:59 PM
BrianO
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p.1 #3 · Electrical Engi question about powering speedlights


ether1 wrote:
...How come nobody thought about building a little AC/DC adapter that would be capable of powering speedlights?


I've had one for my Vivitar 285HV for years. Pearstone still sells them:

http://www.bhphotovideo.com/c/product/638035-REG/Pearstone_239404_SB_4_AC_Adapter.html

The "HV" in 285HV stands for "High Voltage," and it could also use high-voltage battery packs.


Edited on Nov 21, 2012 at 10:37 PM · View previous versions



Nov 21, 2012 at 10:16 PM
400d
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p.1 #4 · Electrical Engi question about powering speedlights


It's odd that the Vivitar adapter is rated only for 200VDC. I believe most of the hot shoe flashes nowadays are 330-350VDC. [From my very limited EE knowledge]: let's say the capacitor in 580EX is 330VDC/1300uF, if it recycles in 1.56s, resistance 1.2kOhm, the max. current draw is 0.275A. Basically an adapter converting 120VAC to 330VDC with a current rating 500mA seems sufficient?


Nov 21, 2012 at 10:28 PM
 

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BrianO
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p.1 #5 · Electrical Engi question about powering speedlights


The problem I see is that while the capacitor's output voltage may be 330 volts, the input voltage to the charging circuit may be less.

Before plugging anything into a jack on a flash, I'd be darned sure what that jack is designed to accept.

(For a Canon Speedlite I assume it would be the same as the output voltage of the CP-E3 or CP-E4 battery pack, which multiple searches indicate is 270 volts.)



Nov 26, 2012 at 06:00 AM
timgangloff
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p.1 #6 · Electrical Engi question about powering speedlights


http://www.innovatronix.com/index.php/webshop/power-supply-adaptors-for-small-flashes/tronix-speedfire-for-canon-flashes-north-american-model-detail


Nov 27, 2012 at 04:16 PM
rodmcwha
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p.1 #7 · Electrical Engi question about powering speedlights


OK, guys, the voltage rating on an electrolytic capacitor is the maximum voltage it can handle, without breaking down---not its"output" voltage!
Be careful playing around in your speedlight, if you don't know what you are doing. There are things in there that you don't want to touch, even after you take out the batteries. It can knock you on your backside!



Nov 27, 2012 at 04:41 PM





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