# Energizer AA E91

Discussion in 'The Projects Forum' started by vin.lwh, Mar 1, 2009.

1. ### vin.lwh Thread Starter Member

Jan 29, 2007
10
0
I'm working on a mobile robot, and it needs 12 volts and approximately 3 ampere. Correct me if I'm wrong, I connect 8 AA E91 batteries in series which is 1.5 volts in order to achieve 12 volts. In order to increase the ampere, I need to connect another 8 more batteries parallel to the original 8. I don't know how much current does the batteries produce.

My questions:
1. What is the maximum current can the energizer AA E91 produces?
2. What other methods can be used to reduce the number of batteries used?
3. How long does it take to drain all the current away from the AA E91 battery assuming my device runs continuously?

I've search the data sheet of the AA E91 but I don't really understand what it means.
http://data.energizer.com/PDFs/e91.pdf

Thanks so much in advance. Really appreciate it.

2. ### wr8y Active Member

Sep 16, 2008
232
1

1. From the link, it appears the battery can provide as much as 1,000 mA (1 amp) - but it won't supply that current for long.

1. The two charts "CONSTANT CURRENT PERFORMANCE" tell it all. The lower of the two charts will tell you how long you can draw 250 mA at what temperatures. Notice how long it takes for cell voltage to drop to any certain level. If you know what minimum voltage your project will accept and what current it draws, you can see how long your project will operate on those batteries.

2. Reduce the load on the batteries.

3. Again, that depends on the current draw. How much current are you taking from the battery?

Go look at those two charts "CONSTANT CURRENT PERFORMANCE". All you need to know to calculate how long the project will run is:

Temperature
Current draw
Lowest voltage that the project can operate on

3. ### wr8y Active Member

Sep 16, 2008
232
1
Oh, and thanks for posting that link. I have looked and looked for those charts on Energizer batteries and never found them!

4. ### Audioguru Expert

Dec 20, 2007
10,822
1,224
Don't use throw away battery cells that do not last long. Instead use rechargeable Ni-MH cells. They have a voltage of "only" 1.2V each but during a discharge the voltage is higher than alkaline cells for most of the time.