The boards i bought For $1.50 seem to fry at 3.3 volts. They just like.. die and never work again. thats why i divided the voltage from the PSU so that the input is 1.5V.
it just takes wayyy to long to charge..
edit: i see a problem with wiring two boards in paralelle. the boards seem to put out 200* the voltage that you put in. If i put two in paralelle on the 3.3V, each board is getting 1.65V... that means the output is 330V exactly... which means its at the limit of my caps.. which is... 330V.
Should i be concerned about this?
If the cameras they are from are 3v, then you'll want to give them no more than that, if its 1.5V, then you'll have to find a better way to step it down rather than using a votlage divider. I would suggest a voltage regulator, such as the LM317. As already suggested a shotky diode in series with the 3.3V power supply would also lower the voltage. Diodes drop voltage across them, and shottky diodes tend to drop about 0.3-0.4V. (normal silicon diodes drop 0.6-0.7V). So a shottky would lower your 3.3V from your PSU to 3.0 to 2.9. If you need 1.5V, then a dirty way of doing things would be to use several diodes in series to drop the voltage. for 1.5v to your boards, from 3.3v form your PSU...3.3-1.5 = 1.8V. Thats 3 (maybe four) silicon diodes. Make sure you use ones rated for 1A. 1N4001's are so common its scary.
So, with your diode in place, wire the power input to the flash boards in
parallel. The voltage will be the same for every board, but they may draw different currents.
Then wire the outputs of these boards in parallel too. Then the caps in parallel, then connect it all up. The outputs of the chargers will have diodes in series with them, so current cannot flow 'back' intop the charging circuit. This means that if one charger is putting out 280V, and another is putting out 310V, the 310V charger won't force current back into the lower power charger. Make sense?
Each charging circuit will produce 280-330V at a small current. The voltage is at the maximum, but for lower charging times, you need current. That is why you wire them in parallel, not series. If each charger outputs 3mA (at 330V), then 5 will output 15mA, reduce you charge time to one 5th. You can just keep adding more because you computer power supply has more than enough current capabilty.
Don't worry about 'over charging' the caps. Yes, over their rated 330v will make them fail, but as long as you stick to what the charging circuits are designed for you should be ok. They wouldn't sell those cheap flashes if they failed after one flash, as long as you can emutlate their power supply without going over it. (1.5V if it took a single AA, 3v for two). Measuring the output voltage of these little chargers won't be much use unless its charging a cap. Open circuit (no capcitor connected) its voltage will soar, and possibly destroy your circuit. It was never designed not to have a cap connected.
If you need a diagram I can draw a simple one up for you.
Blueteeth