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I'm trying to find out the current needed to power a Godox MS300 photography flash (Official specs at the end of the page). I'm using the 220V version, and it says that at max power, the output is 300Ws [*1], for which it takes 1.3 seconds to charge.

I'm wondering if it's as straight forward as:

\$\frac{300Ws}{1.3s} = 231W\$

And then

\$\frac{231W}{220V} = 1.05A\$

If I'm getting it wrong, is there a way to calculate the current needed with the data given by the manufacturer? Even an aproximate would work.

*1: The modeling lamp has a 150W consumption, but that is a different light than the flash itself.

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  • \$\begingroup\$ the document states that the device uses 150 W ... the 300 Ws is the output of the device, not the amount of power it uses \$\endgroup\$
    – jsotola
    Commented Aug 23, 2021 at 21:44
  • \$\begingroup\$ @jsotola, the 150W is the usage of the modeling lamp ("preview bulb"), not the flash itself, I'll add it to the question to avoid confusion. \$\endgroup\$
    – FercoCQ
    Commented Aug 23, 2021 at 21:58

1 Answer 1

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The 150 W is for the modeling lamp. Average power during charging would be an additional 231 W plus the losses in the charging circuit. The charging circuit may not be very efficient, so you could see over 600 watts chargnr with the modeling light on. That may be another 230 watts. The short-time power shouldn't be much of a problem unless you shoot a lot of pictures in a short time.

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  • \$\begingroup\$ So if minimum strobe interval is 1.3s continuously , or 230Ws and minimum flash duration for 300Ws/ 0.5 ms = 600 kWatt but the mystery is output energy 300Ws is greater than the input energy of 230 Ws every 1.3w (??) . So I conclude it cannot sustain this flash rate at max power. \$\endgroup\$
    – D.A.S.
    Commented Aug 23, 2021 at 22:30
  • \$\begingroup\$ @TonyStewartEE75 You can't trigger the flash continuously, you have to wait for it to charge. Cheaper flashes might take even longer to charge, and still be able to discharge those 300Ws when you trigger them. \$\endgroup\$
    – FercoCQ
    Commented Aug 23, 2021 at 22:45
  • \$\begingroup\$ The specs say otherwise. 220Vac 0.1 to 1.3 recycle time. So they didn’t say the accurate limits \$\endgroup\$
    – D.A.S.
    Commented Aug 23, 2021 at 23:31
  • \$\begingroup\$ The range listed for the recycle time probably reflects the ability to charge to less than full voltage to reduce the flash power. The flash has an over-temperature protection feature. That suggests that it is possible to overheat it by sustained rapid flashing., but the manual doesn't seem to say anything about that. \$\endgroup\$
    – user80875
    Commented Aug 24, 2021 at 0:05
  • \$\begingroup\$ The 1.3 recycle time should be the expected time for a full power charge (the whole 300Ws), but you can adjust the power down to 1/32 if needed, so I expect the 0.1 recycle time to be the time needed to charge 1/32 of 300Ws. \$\endgroup\$
    – FercoCQ
    Commented Aug 25, 2021 at 0:15

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