Originally Posted by
My ST-RR EVO
A power supply converts ac current (the type of current that comes out of your wall or extension cord) to DC current (the type of current that comes out of your full size car battery or any battery for that matter). The benefit of a separate power supply is the wattage they make. A 1200 watt power supply can charge batteries a lot faster than say a HiTech x4 ac / dc charger that only pumps out 50 watts per channel. My opinion is that a high performing power supply should be built into the charger. I don't want to be carrying around two separate items. I'm assuming batteries need to be charged by dc current.
The bolded section is not correct. A power supply CANNOT charge a battery without a charger. and then, you are limited by what the CHARGER can output, not the PS.
Example - If you have a 1200W PS, and a 50W DC charger, you will only be able to charge at 50w max. That 50w charger will never charge a 4s pack above 3.4a, regardless of the PS size...
Also the opposite is true too - the charger can only output what the PS can supply. I currently have a charger capable of outputting a total of 600w, but my PS is limited to about 330 watts - so I must pay attention an not set my charge rates too high and overload the PS.
To charge at high wattage / hi amperage, you need a BOTH a PS and a charger that are rated for the desired charging rates.
The math is pretty simple. Amps X Volts = Watts. or Watts/volts = amps.
So if you have a 4s 5000mah pack, and want to charge at 1c /5a, the math is -
5a * 14.4v = 72w - you need 72watts of power to charge that battery at 1c/5a.
One more "Got-ya" when shopping chargers - multi-channel chargers will sometimes be rated by their TOTAL wattage, when each channel can't use that full wattage. Example - my old charger was a 2 channel, "100w" charger. It could charge 2 batteries separately , to a TOTAL of 100w. Charging only one battery, though, it could only charge 50w.
Some 4 channel, 50w per channel charges are sold as "200w" chargers, but they can only put 50w to each channel...
Example -
This Charger is listed as a "320w" charger - it says 320w all over the add copy, but each channel can only make 80w - 80w x 4 channels =320w, so they are not wrong. To me, however, it is a bit deceptive.
Be sure to read into the specs to see what the amperage and wattage is for each channel.