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I've been searching all over the web and couldn't find a simple answer to my question. Partially because I'm no electrical engineer, so I really need a simple and direct answer.

My question is if you have a portable battery with the same output voltage as the input voltage on your device, does the amp matter?

A little more background. I'm trying to power a PAM8403. I was wondering if this battery can be used https://www.google.de/url?sa=t&source=web&rct=j&ei=YF2bVa28OsH8UIHKmJAL&url=http://www.adafruit.com/products/1566&ved=0CBwQFjAA&usg=AFQjCNF5zVB0SBjyOxSfughSyLLrkuZAVQ&sig2=t5OVPEnTbJfaZBYtfonXeQ

Would any portable batteries used to charge android phones work, for example?

Thanks a lot

Fred
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PAM8403 can give 3.2 W of output and its quiescent current is 16 mA at 5 V. hence total load can be considered as 3.3 W Maximum. At 5 V , it translates to ~0.66 A of current when working at full load.

The battery capacity is 10000 mAh. Since, there are no more details on the internals of the battery, i am going to assume 8000mAh (8 Ah) of charge will be available to the user.

hence, 8 Ah / 0.66 A = ~12.12 hours. PAM8403 can be driven for more than 12 hours with the suggested battery at full load. The suggested battery turns off itself if there is very low load current for certain duration (Think, speakers muted!), in order to keep the battery on this circuit is suggested by the seller.

User323693
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You're trying to match up a power source with a load.

The rated output voltage of the source has to match the input voltage that the load wants.

The rated output current of the source also matters, but it doesn't have to match the load current. It just has to meet or exceed the load requirement.

The source current (in Amps) has to be at least as much as what the load wants. If the source is rated to provide 2.0 Amps and the load only draws 1.7 Amps, that's OK. But if the load wants to draw 2.5 Amps out of a source that's only rated to provide 2.0 Amps, then the source won't be able to supply enough power, the source voltage will decrease, and the load won't work correctly (or maybe won't work at all).

MarkU
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