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Topic: Battery voltage dropping upon connection (Read 927 times) previous topic - next topic

rptort

I wasn't sure where to post this cuz its not a mechanical/high voltage issue, but it does have to do with power. I need a 5V supply for my circuit but I also need a small battery. So I'm using two stacked coin cell batteries (3V each) and regulating that down to 5V. However upon connecting the power to the circuit, the voltages on the battery and the output of the regulator drop quite a bit. Is this simply because the battery can't source enough current to the circuit?

Thanks!

RuggedCircuits

Yes, it's quite possible. Coin cell batteries generally aren't used for significant currents, and likely have high internal resistance.

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retrolefty

#2
Mar 24, 2012, 08:32 pm Last Edit: Mar 24, 2012, 08:34 pm by retrolefty Reason: 1
Quote
However upon connecting the power to the circuit, the voltages on the battery and the output of the regulator drop quite a bit. Is this simply because the battery can't source enough current to the circuit?



That is correct. The battery has to be selected for the maximum load current it is being asked to supply. Also how long you wish to battery to be able to supply that load current is another selection criteria you must make.

Lefty


Grumpy_Mike

Quote
Is this simply because the battery can't source enough current to the circuit?

How much current are you asking of it?

jackrae

If they're something like CR2032 then they are rated at less than 1mA, which is a lot less than your micro is demanding.  Coin cells are really not suitable as a power source for anything other than memory retention or running RTCs.









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