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Maker Pro

Portable Strobe Battery Pack.

Eric Downs

Jun 11, 2015
1
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Jun 11, 2015
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Hello. I am wanting to build a battery pack for this unit. http://www.adorama.com/fp1820a.html Could I get some recommendations for a inverter and a battery?

Would this work and is it overkill?
http://www.amazon.com/gp/product/B000NIG2FG/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

I know I will need a sealed battery but I just cant not figure out how many AMP/HOURS I will need. Say I will be using this flash at full power every 10 seconds in 60 mins. So that would be 360 seconds or 6 mins.? Do I need a very large battery?

Thanks for any replies.
Eric
 

Martaine2005

May 12, 2015
4,278
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May 12, 2015
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4,278
Hi Eric, The inverter would more than likely be fine, as a little extra headroom would avoid thermal shut down.

The sealed battery would have to be trial and error I think..Due to flash and inverter running off the battery.
Perhaps a 12AH to start and do some testing on how long it lasts.

However, my concern would be using it in sync with an expensive camera. These inverters are not pure sine wave and interfere with delicate electronics.
I wouldn't trust what it says about 'laptops, cameras etc.

Just my two cents worth.
Martin.
 

AnalogKid

Jun 10, 2015
2,665
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Jun 10, 2015
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2,665
The inverter is overkill, and that will cost you efficiency and battery time. Do you need to power the modeling light when on battery power? If not, a 400-500 W inverter should be plenty. Let's whip out a coctail napkin and run some numbers.

900 W-s total energy over a 3 second cycle time is 300 W for three seconds. At 75% efficiency, the battery has to supply 400 W / 12 V = 33 A for 3 seconds for each full-power shot, plus some margin for startup transients. 3 seconds is 1/1200th of an hour, so each full power shot is 0.0275 A-h. So you need a relatively small battery with gigantic peak current capability. Peak currents can warp the plates in a SLA battery. Get a battery that can handle the peak currents and you should get plenty of shots, even with running the flash electronics and fan between shots.

ak
 
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