View Full Version : Power supply question
T-wrecks450
11-05-2007, 06:10 PM
Can chargers be over-amped? I was told no, but I'm no electrican so I figure I ask first before I blow my brand new charger. I have a power supply that is 12V DC, but my volt meter can only measure 10A max.. when I try to take a reading it always giving me an overloaded reading. I read through my charger manual (Hyperion 1210i) and didn't see a maximum Amps listed just minimum 8A, so I am thinking it doesn't matter what it is, it will use what it needs and that is it. Is that correct or should I just scrap it and buy a new one? I hate to spend money on a power supply when I could use it for more packs. Anyway, thanks for the input guys.
Update: I did some more research and found that it is a 300w rated power supply, so 300w/12V = 25amps. I think it should be ok. Everyone agree? Anyone Disagree?
Pinecone
11-05-2007, 10:50 PM
No, the charger will only draw what it needs.
If you tried to measure amps just between the terminals of the power supply, you aer basiclaly shorting out the power supply. Don't do that. :)
ghtracey
11-07-2007, 05:05 PM
No, the charger will only draw what it needs.
If you tried to measure amps just between the terminals of the power supply, you aer basiclaly shorting out the power supply. Don't do that. :)
LOL Speaking of blowing that brand new charger....
If you are trying to measure how much current its pulling, you would put the ammeter one the positive input power lead, red to the supply, black to the charger. Worry more about your charger blowing your power supply than the other way around. You can work out how many amps your charger needs like this.
(I'm using rated voltages here, not peak so draw may be higher)
Power = Voltage * Current
ex1) Charging 3S1p 2000mah at 1C
P=IV=11*2=22W.
P=IV so I=P/V=22/12=1.83A. You are pulling 1.83A from the supply.
Now say you are charging a 6S1P 3700mah at 1C
P=22*3.7=81.4W
I=81.4/12=6.78A
From this you can see where the watt rating on your charger comes into effect. Also, the efficiency of the charger is not perfect and they will draw more from the supply than you calculate.
T-wrecks450
11-11-2007, 10:04 AM
Thanks guys, :noteworthy now I have a little more understanding on how this works.