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Topic: What is the max current I could draw from a 9V battery? (Read 13 times) previous topic - next topic

encryptor

What is the max current I could draw from a 9V battery?  I'm looking to draw 150 mA aka 0.15A  from a power source.  Does a 12V battery have a higher current rating? :~
peace*&^

dhenry

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What is the max current I could draw from a 9V battery?


I don't think the answer depends on which 9v battery you are talking about right? I can draw about 5ma out of my wimpy 9v battery and I think your super-duper 9v battery can do no better.

jackrae

#2
Nov 12, 2012, 10:48 pm Last Edit: Nov 12, 2012, 10:50 pm by jackrae Reason: 1
If you are talking about a PP3 style battery, the alkaline version has a capacity of around 600mAH.  So for any sensible lifespan you are looking at a useful maximum of around 30mA.

Battery capacity is usually a measure of AH capacity and is based on physical size rather than rated voltage.  In essence a large battery has greater capacity than a smaller one of the same voltage and hence may be considered as capable of greater current capability.

As to maximum current, it all depends on chemistry, how long you want to draw current, how much money you have to spend, etc.  As a simple rule, I would suggest you use AH/20 as a useful yardstick.   The current versus AH capacity is not linear.  For example, taking the above example, you might only get 10 hours at 30mA (300mAH) but you might get 1500 hours if you only drew 1mA (1500mAH).

If you have a particular battery in mind, simply enter its model into a google search and somewhere in there you'll get an AH capacity rating (that's what I did to establish the first line, above)

retrolefty


What is the max current I could draw from a 9V battery?  I'm looking to draw 150 mA aka 0.15A  from a power source.  Does a 12V battery have a higher current rating? :~


Depends on the specific battery you are talking about. A 12vdc lead acid car battery can supply a lot more continuous current then a much smaller 12 volt battery. Small 9 volt batteries are designed to power smoke alarms for a couple of years but won't supply 150ma for even a day.

Lefty

DVDdoug

Here is the datasheet for a Duracell 9V battery.  They don't list a "maximum" current.  From the graphs, at 50 mA it looks like you are down to 7V in 5-10 hours.   

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