Real battery capicity (tank capacity / Amper rating ?)

Now a days mobile phone comes with different batteries rating 1000mah to 4000mah. but actually any mobile phone takes current to some extent only.so how can we justify that a battery with larger ampere rating give more backup. Because for example a 1.5v *2 AA battery lasts long than a 3.7v mobile li-on battery(650ma appox.) with used for same load.Finally I assume that a battery with more size or amps to considered when buying?

A battery that can provide more electrical energy will give more backup. E = V * I * t. So, t = E / (V * I).

For same voltage, greater current rating means the battery stores more chemical energy and can thus convert more to electrical energy than a battery with a lower current rating. So, for same voltage, greater current rating means greater backup time.

Because for example a 1.5v *2 AA battery lasts long than a 3.7v mobile li-on battery(650ma appox.) with used for same load.

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This depends on the specifications of the batteries themselves. The current rating of the AA batteries you're referring to is probably much higher than that of the mobile phone battery.

Hope this helps.
Tahmid.

rajakumarn said:

Now a days mobile phone comes with different batteries rating 1000mah to 4000mah. but actually any mobile phone takes current to some extent only.so how can we justify that a battery with larger ampere rating give more backup. Because for example a 1.5v *2 AA battery lasts long than a 3.7v mobile li-on battery(650ma appox.) with used for same load.Finally I assume that a battery with more size or amps to considered when buying?

Click to expand...

You cant compare non rechargable batteries such as alkaline 1,5 with rechargable Li-Ion 3,7V. But you can compare NiMh (1,2V) with Li-Ion.

Alkaline 1,5V can have capacity around 1800-2600mAh.

When we speak about mobile devices, size and shape of batteries have major role. Li-Ion can be very thin. Number of recharging cycles,....

Price - Size - Capacity - Reliability