I have a question about battery consumption.Let say my battery has voltage of 6V and capacity of 11 mAh. It has to power up the circuit consists of microcontroller (5V, 50 mA), bluetooth module(3V, 20 mA), gyroscope(3V,10 mA). How to calculate the power consumption of the circuit.And how long the battery can last long to power up the circuit.Can it be longer than 5 hours? If not what can I do? I dont want to use external power supply and 11 mAh battery is the maximum energy capacity that I can have.
2007-08-27 11:09:29 · 3 answers · asked by Ikmal 1 in Science & Mathematics ➔ Engineering
how to make it last long up to 5 hours?Is there any rechargeable coin battery that have capacity a lot larger than 11 mAh
2007-08-27 11:27:30 · update #1
In order to compare apples to apples, you need to convert your voltages and currents to power. Your battery can do 6V@11mAh, therefore 66mWh. Your processor is consuming 5V@50mA, or 250mW, your bluetooth is consuming 3V@20mA, or 60mW and your gyro is 3V@10mA, 30mW. So your device is consuming a total of 340mW (assuming everything else is perfect, which it isn't). So if your battery can provide 66mWh, then it can produce 340mW for .194h, 11.6 minutes. Of course, your battery probably derates the capacity based on discharge rate, I'm guessing a 11mAh battery won't even produce 340mW (57mA@6V) even as a surge, but that is dependent on battery chemistry. Also these numbers assume that your conversion from 6V to 5V and 6V to 3V are 100% efficient, which they aren't by any stretch.
2007-08-27 11:31:39 · answer #1 · answered by EE dude 5 · 0⤊ 0⤋
Right away I see a problem with getting any significant time from that battery.
The microcontroller is using 50 mA,while the battery is supplying only 11 mAhr (the voltages are close enough -- the DC-DC converter to get the battery voltage regulated to 5 V would eat up that 20% difference in inefficiency, anyway).
The battery capacity for the microcontroller, alone, is only going to be about 10 to 13 minutes (11/50th of an hour). Add on the other 2 components, and your battery will be lucky to last 5 minutes .
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2007-08-27 18:19:16 · answer #2 · answered by tlbs101 7 · 0⤊ 0⤋
I have to go so i have no time to do the math for your but
Take the volts times amps of the battery to get the watts
Do the same for the others parts, add them together and divide it will tell you the hours.
By the looks you might get 10 minutes.
2007-08-27 18:23:43 · answer #3 · answered by Yoho 6 · 0⤊ 0⤋