Operation Hours for LiPo Battery

I am using a LiPo battery and the specs is below:
Capacity: 4.4 Ah
Discharge Rate: 60 C
Voltage: 22.2 V

I am using a LiPo battery to power up two motors and the current required is about 14 (A).

How can I calculate the operation hours for my battery?

I'm not sure what the spec is saying. Is the quoted Discharge Rate the maximum allowable rate, or is it the rate for which the battery will have a guaranteed 4.4Ah capacity?

alec_t said:

I'm not sure what the spec is saying. Is the quoted Discharge Rate the maximum allowable rate, or is it the rate for which the battery will have a guaranteed 4.4Ah capacity?

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maximum allowable rate

According to the specs, the battery will be fully drained after 18 minutes.
(4.4Ah / 14A) = 0.31 h

As you discharge the battery, the voltage will drop. Over discharging kills your battery very fast.

For safety you should not never discharge a LiPo pack down past 80% (3.75V per cell) of it's capacity. So if you take that into account you have:
0.31 h * 0.8 = 15 minutes

misterT said:

According to the specs, the battery will be fully drained after 18 minutes.
(4.4Ah / 14A) = 0.31 h

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Maybe.
We don't know if the motor is working hard, working a little or idling.
My electric RC airplane uses 50mA when cruising or 4A when climbing vertically at full power. The duration of a battery discharge varies a lot depending on how hard it works.

For safety you should not never discharge a LiPo pack down past 80% (3.75V per cell) of it's capacity. So if you take that into account you have:
0.31 h * 0.8 = 15 minutes

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No.
The battery is safe to discharge each cell down to 3.2V. The cells are pretty-well matched.
Each cell is 4.20V when fully charged.
The 22.2V battery has six 3.7V cells in series (for a total of 22.2V) so each cell is 3.7V when half-discharged.

audioguru said:

Maybe.
We don't know if the motor is working hard, working a little or idling.
My electric RC airplane uses 50mA when cruising or 4A when climbing vertically at full power. The duration of a battery discharge varies a lot depending on how hard it works.

Click to expand...

Yes, of course. I just wanted to give the "naive" answer to the original question, so the OP has a chance to understand the math.

audioguru said:

No.
The battery is safe to discharge each cell down to 3.2V. The cells are pretty-well matched.
Each cell is 4.20V when fully charged.
The 22.2V battery has six 3.7V cells in series (for a total of 22.2V) so each cell is 3.7V when half-discharged.

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I checked the numbers from this page: https://www.rchelicopterfun.com/rc-lipo-batteries.html
Is the information there wrong, or did I misread something?

killer_fighting said:

I am using a LiPo battery and the specs is below:
Capacity: 4.4 Ah
Discharge Rate: 60 C
Voltage: 22.2 V

I am using a LiPo battery to power up two motors and the current required is about 14 (A).

How can I calculate the operation hours for my battery?

Click to expand...

If you are discharging at 14A, that's about 3X the "C" rate so your battery will likely deliver maybe 80% of it's rated C rate (rough guess, the manufacturer should have a graph for this). The specified C rate is usually for a discharge rate of about c/10. At higher discharge rates, there are a lot more internal losses so the C rate is much less. So assume it's now a 3.5A-hr battery. At 14A, the battery will last about 3.5/14 hours or maybe 15 minutes.


The curve below shows how battery capacity drops at higher currents.