Calculating Battery cells?

Question

Hi all can anyone help me with my equation. I am trying to make a 14.4V 1.3Ah Battery using 14 individual cells linked together. only the problem is I don't know or understand the eqautions required to work out which ratings of cells to use if anyone can help it would be greatly appreciated.

Answer 1

Put the cells in series (stacked one on top of another) to add voltages, keep same Ahr rating of each cell.

For Alkaline batteries, AA has over 2Ahr, so putting 10 in series gets it for you.

http://data.energizer.com/SearchResult.a...

Nickle metal hydride or rechargeable alkaline may make it with AA cells, especially for low current draw. Same number of cells.

For NiCads, the AA is probably not capable of putting out the energy you want, need to go with C cells. 12 cells or so should do it.

Answer 2

You want to end up with 14.4 volts with an amp-hour rating of 1.3 amp-hours.

I don’t think a solution is possible without knowing what cells you have to work with. And, here are two examples of why I can’t do it.

Number One: A 12 volt car battery has six cells because the difference across the terminals of one lead-acid wet cell is two volts. The battery hooks up the cells in series, and you end up with 12 volts. Now if you made a battery with the same materials the size of your bath tub you would still have 12 volts. But that bathtub size battery would last much longer.

Number Two: Consider the common flashlight battery; a small AAA cell in a penlight flashlight will go dead long before a D size will (assuming the same bulb), yet they’re both 1.5 volts.

Then we have wristwatch batteries, hearing aid batteries, and others. All of which will create the same voltage within their group, but they too come in many sizes.

Thus, with the information provided in the question, an answer seems impossible to me.

Answer 3

Exactly 14 cells?

6 lead acid cells at 2v each will give you about 12 volts, 7 will give you 14 volts.

Two of these batteries in parallel will give you about 14 volts also.

Since you have a series parallel connection, each cell has to deliver half of 1.3 amp-hr or 0.65 amp-hr.

14.4? Batteries are not that accurate, with an implied accuracy of 1%. You will get about 14-15 volts.  When being charged you will get 16-17 volts. When low on charge, 12 volts.

Answer 4

When you are combining rechargeable batteries, the voltages add when you put them in series, and the amp-hours for the group are the same as for one cell, because the current is the same for all of them.  If you put them in parallel, you have the voltage of one cell (usually about 1.2 volts for lead-acid or Ni-Cd batteries), and the sum of the amp-hours.  So with 12 batteries in series, you would get about 14.4 volts, with the Ah rating of the individual cells.