Battery life calc with on/off duty cycle

J

Joe G $$Home$$

Jan 1, 1970
0
Hi All,

I would like to estimate the battery life of my Rx receiver which has an
ON/OFF (wakeup / Stdby) duty cycle.

1st I calculate the average current

Current Av = [(Iwake * Twake) + (Istdby *Tstdby) ] / [Twake * Tstdby]

Where
Iwake is ON or wakeup current (mA)
Twake is wake up period (s)
Istdby is OFF or standby current (mA)
Tstdby is standby period (s)

When I know the average current I can work out the average battery life

Hours = mAh / Current Av

OK so far?

Any other ways of looking at these calc's would be appreciate

Joe.G

I

Ian Stirling

Jan 1, 1970
0
Joe G $$Home$$ said:
Hi All,

I would like to estimate the battery life of my Rx receiver which has an
ON/OFF (wakeup / Stdby) duty cycle.

1st I calculate the average current

Current Av = [(Iwake * Twake) + (Istdby *Tstdby) ] / [Twake * Tstdby]

Where
Iwake is ON or wakeup current (mA)
Twake is wake up period (s)
Istdby is OFF or standby current (mA)
Tstdby is standby period (s)
OK so far?

Looks OK.
Any other ways of looking at these calc's would be appreciate

Energy.
Battery has N joules (power * time).
Look at powers.

Also, in real life, depending on battery chemistry, it may be inaccurate.
How inaccurate depends on pulse rate, battery chemistry, internal resistance,
....
If you're never discharging the battery faster than 1C, it's probably OK.

J

Joe G $$Home$$

Jan 1, 1970
0
Thanks Ian.

I'll do some calc's with power and time.

Regards
Joseph

Ian Stirling said:
Joe G $$Home$$ said:
Hi All,

I would like to estimate the battery life of my Rx receiver which has an
ON/OFF (wakeup / Stdby) duty cycle.

1st I calculate the average current

Current Av = [(Iwake * Twake) + (Istdby *Tstdby) ] / [Twake * Tstdby]

Where
Iwake is ON or wakeup current (mA)
Twake is wake up period (s)
Istdby is OFF or standby current (mA)
Tstdby is standby period (s)
OK so far?

Looks OK.
Any other ways of looking at these calc's would be appreciate

Energy.
Battery has N joules (power * time).
Look at powers.

Also, in real life, depending on battery chemistry, it may be inaccurate.
How inaccurate depends on pulse rate, battery chemistry, internal
resistance,
...
If you're never discharging the battery faster than 1C, it's probably OK.