AH capacity calculation ??? Please help !!
AH capacity calculation ??? Please help !!
(OP)
Hi all ,
I have a unit that consumes 3A at 12V. It is delivering high voltage pulses with following numbers
4 channels
100mA max drain current into 4K load .
Max pulse width is 1mSec .
100 Pulses per second per channelx 4 = 400 Pulses
So i calculated as
(100mA)2 x 4k X 1mSec x 400 = 16W per second
makes it 57.6KWh and what next for Ah?
Doesn't this value look big??
With this i get the battery capacity of 12v / 30Ah for sustained operation for 8 hours .....
Am i doing something wrong??? somehow something is missing somewhere
Please help me with this Watt-hour to Ampere hour calculation.....thanks in advance
I have a unit that consumes 3A at 12V. It is delivering high voltage pulses with following numbers
4 channels
100mA max drain current into 4K load .
Max pulse width is 1mSec .
100 Pulses per second per channelx 4 = 400 Pulses
So i calculated as
(100mA)2 x 4k X 1mSec x 400 = 16W per second
makes it 57.6KWh and what next for Ah?
Doesn't this value look big??
With this i get the battery capacity of 12v / 30Ah for sustained operation for 8 hours .....
Am i doing something wrong??? somehow something is missing somewhere
Please help me with this Watt-hour to Ampere hour calculation.....thanks in advance





RE: AH capacity calculation ??? Please help !!
0.1 amp 1/10 duty cycle = .01 amp per channel
Times 4 channels = .04 amps
Times 8 hours = 0.32 amp hours
RE: AH capacity calculation ??? Please help !!
"I have a unit that consumes 3A at 12V"
Isn't that 8 Hr * 3 A = 24 AHr for 8 hrs operation?
TTFN
RE: AH capacity calculation ??? Please help !!
or
400ms of 100mA per second
100mA x 0.4s = 40mA average current.
40mA x 8 = 0.32Ah
Odd.
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: AH capacity calculation ??? Please help !!
The input side seems fairly clear. The battery is (I assume) on the 12 volt input. If the box needs 3 amps (continuously), then for 8 hours you'd need 3 times 8 = 24 amp hours.
Since the frequency is relatively high (100 pulses per second - as compared to the normal meter) I assume that the 3 A is an average value (if not already filtered internally).
You should double check the low voltage definitions for both the battery and the box. If the box shuts down at 11.999 volts (an exaggeration for clarity), then you wouldn't get all of the spec'd Ah out of the battery.
RE: AH capacity calculation ??? Please help !!
Thanks for the replies . sreid , i guess 0.32Ah will not work since circuit is consuming 3A approx continuously.
IRStuff, u;r right . i missed 20% addition for battery heat and losses. Also i forgot to mention the other parts of circuit which though fairly low power, but consume some power and 30Ah being standard in the market, i mentioned that number in my previous post....
IR : I got the same exact numbers as you do...but wanted to double check since i m going to be recommending a car battery for handheld / portable unit ...:)
Not me guys !!! Guys who developed specs !!:)
RE: AH capacity calculation ??? Please help !!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: AH capacity calculation ??? Please help !!
RE: AH capacity calculation ??? Please help !!
RE: AH capacity calculation ??? Please help !!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: AH capacity calculation ??? Please help !!
TTFN
RE: AH capacity calculation ??? Please help !!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com