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01-11-2005 | 03:47 AM

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Direwolf

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From: Rapid City, SD

RE: Lipos in parallel ?

This'd be a good time to dust off a physics text book if you have one handy. But, here's what you need to know...

A battery is a group of cells.
A cell has a capacity, measured in Amp*Hours (pronounced "Amp Hours" ), abbreviated as "Ah".
A cell has a certain amount of potential to do work, measured in Volts, abbreviated as "V".

When you put cells in series, their voltage is added together. For example:

Code:

    -----&gt; [- 3.7V +] [- 3.7V +] [- 3.7V +] -----&gt;

This battery has 3 cells in series, so this is called a "3S" battery. The total voltage of this battery is 3*3.7V = 11.1V.

When you put cells in parallel, their capacity is added together. For example:

Code:

      .--&gt; [- 1.2Ah +] --.
   ---|--&gt; [- 1.2Ah +] --|---&gt;
      '--&gt; [- 1.2Ah +] --'

This battery has 3 cells in parallel, so this is called a "3P" battery. The total capacitance of this battery is 3*1.2Ah = 3.6Ah.

You can use combinations of cells in series and in parallel to achieve different levels of Voltage and Capacitance. For example:

Code:

       .--&gt; [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +]--.
    ---|--&gt; [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +]--|---&gt;
       '--&gt; [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +] [- 1.2Ah, 3.7V +]--'

This battery has 3 parallel groups of 4 cells in series, so this would be called a "4S3P" battery.
The total voltage of this battery is 4*3.7V = 14.8V, and the capacitance of the battery is 3*1.2Ah = 3.6Ah

Hope that helps.

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