R/C Tech Forums - View Single Post - using computer server power supply for charging station
Old 02-13-2013 | 02:31 PM
  #17  
Dave H
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Joined: Oct 2007
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Originally Posted by youwish16
i know how to make them but i dont know about all the numbers. can someone explain?

say i have a charger that charges 4 2s batteries at once at 5 amps each, how would i determine the minimum power needed from a power supply?
Basic equation: Voltage x Amps = Watts

For the case mentioned, including allowance for charger efficiency:

4 lipos x 8.4V full charge x 5A / 80% charger efficiency = 210 watts

Most power supply manufacturers recommend ~30% extra for reliable operation: 273 watts.
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