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Question on Total current draw

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Toleedo

New Member
I was wondering how to add these up for total current draw in a day

Current draw will be 27.65mA 3 times a day and it last 40.24 s
Current draw will be 21.64 mA 1 time per minute for 12 ms
Current draw will be 6.13 uA all other times

So for 120.72 s per day current draw will be 27.65mA, for 17.26 s per day it will be 21.64mA and for 86, 262.74 s it will be 6.13 uA.

So about 99.84% of the time it will be 6.13uA, 27.65 mA about 0.14% of the time, and 21.64mA about 0.020% of the time. I am just not sure how to add all these up for total current draw during a 24 hour period...probably pretty easy and I am a bit rusty.

Thanks
 

crutschow

Well-Known Member
Most Helpful Member
To get the average current, multiply the current draw by the percentage each are on in each day and add them together.
 

JimB

Super Moderator
Most Helpful Member
You are probably confusing yourself by using the expression "total current draw".
What I think you really want is the quantity of charge used in order to calculate battery life, yes?

So,
27.65mA x 3 x 40.24s = 3337.9 mA.s (milli-amp seconds)
21.64mA x 60 x 24 x 0.012s = 373.9 mA.s
0.00613mA x 86262s =52.87 mA.s

add it all up:
3764.67 mA.s or about 1.05 mA hour if I have understood your figures correctly.

JimB
 

Toleedo

New Member
Thank you both, I did what both of you recommended, but kept thinking, am I doing this correctly...thank you for the confirmation.
 

Ratchit

Well-Known Member
I was wondering how to add these up for total current draw in a day

Current draw will be 27.65mA 3 times a day and it last 40.24 s
Current draw will be 21.64 mA 1 time per minute for 12 ms
Current draw will be 6.13 uA all other times

So for 120.72 s per day current draw will be 27.65mA, for 17.26 s per day it will be 21.64mA and for 86, 262.74 s it will be 6.13 uA.

So about 99.84% of the time it will be 6.13uA, 27.65 mA about 0.14% of the time, and 21.64mA about 0.020% of the time. I am just not sure how to add all these up for total current draw during a 24 hour period...probably pretty easy and I am a bit rusty.

Thanks
You can get the "total current draw in a day", but it will constantly change every instant depending on when the three different sources turn on. Therefore, run a recording ammeter for 24 hours and read the chart for the time you are interested.

If you want the average current, compute the amount of charge in coulombs as JimB has shown you. Then divide by the number of seconds in a 24 hour day to get the average daily current in amperes.

Ratch
 

hyedenny

Active Member
I was wondering how to add these up for total current draw in a day
Are you looking for average current? It sounds more like you're looking for total power used. Amp-hours, or watts.

Edit: Whoops, someone beat me to it. SORRY!
 
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