

United States, MO, St Peters
Joined Oct 2003
28 Posts

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Thanks for your time....Brian 





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Bummer, out of stock already...will you post here when more are available? 




Many power supplies do fluctuate their output voltage when there is no load on them. Normally the voltage tends to rise a lot, and the circuitry has trouble maintaining the output voltage with no load on it.

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The ones I use and sell are rock steady according to my voltmeter. I don't have a scope.




Newbie Needs help :)
I have a server power supply that I bought from classifieds. I do not know what brand. I do know that it is producing 12 volts.
How can I discern the amps that it is capable of producing? According to my Icharger 206B, the charger should be producing 200 watts at 12 volts. Is there a way to test that? I have tried to charge my 3300, 6s lipos at 5C, but even though I set my charger at 15 amps, it only runs up to a little over 10 amps if I remember correctly. Obviously the power supply is holding the Icharger back because it COULD produce 300 watts at 18 volts. But how does one know how many WATTS it will take to charge a 3300 Mah, 6s lipo at 15 amps? What is the formula for ciphering? If this is not the correct thread for this question I apologize and ask if someone would direct me? Thanks so much!!! 







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Volts X amps = watts




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I have done some closer looking at my power supply. It is a Dell Switching supply. It claims that it can produce 502 watts Max If I understand the symbols correctly, it state that at 5 volts it produces 2 amps and at 12 volts it produces 41 amps. Of course 12 volts times 41 amps equals 492 watts so that is the Max they state.... Now my Icharger says it produces 300 watts at 18 volts so I assume that means it produces 200 watts at 12 volts. What I still don't understand is 1. what is the limiting factor of my system that prevents me from charging my 3300 6s lipo at 5c? 2. how to I discern what the limiting factor is? Is it because I am trying to charge a pack to 22 volts and I only have 200 watts at my disposal therefore I can only get up to around 10 amps? 




If that is the case then the Dell power supply is the limiting factor.
SO the next question is how do I go to an 18 volt Power supply. I assume that the Icharger can not take 24 volts so I can not just put two of these Dells together.... 



Oops... More info:
Here are the specs for the Icharger: Input voltage range: 10– 28.0VDC Charge current range: 0.05 – 20.0A Discharge current range: 0.05 – 20.0A Maximum charge power capacity: 300W @ input voltage > 18V Maximum discharge power capacity: 20W Maximum regenerative discharge power capacity: 300W Maximum extern discharge power capacity: 500W @ 25V/20A Seems to me that the specs say that it can run on as many as 28 volts DC. Which means I need to get a 24 volt power supply yes? It also says its maximum charge capacity is 300 watts at 18 volts. Which I believe means that I can charge at 16.6 amps? 



Usually the limiting factor is the charger limits out on either watts or amps.
But you do need to feed the charger with enough power. These little chargers are pretty sophisticated. They take 12v input and boost it the 25.2V to charge a 6S pack. The specs for the charger should tell you what input is required to get full output. Your batteries require  16.5AMP to charge at 5C and that is 415watts. Your charger wouldn't provide that. 
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