# Dry cells

Discussion in 'The Projects Forum' started by Lightfire, Feb 10, 2011.

1. ### Lightfire Thread Starter Well-Known Member

Oct 5, 2010
690
21
Hello, maybe this is the very EASY and ANYONE can EVEN determine the answer but since I am not belong to those, here I AM asking.

First,

If for example, I had 8 1.5 volts battery (AA) and I connected each others. So after I connected each others, I will have 12 volts, right?

So, now, I had a 12 v halogen lamp (which is let's say 50 w), do those batteries can operate this halogen lamp well? As same as what what wet cells power gives.

OR batteries have their own specification or whatever?

OK,

This one is very easy easy easy and I can even determine. But I'm just correcting myself.

OK. Let's say here's the 8 1.5 (AA) batteries.

- +- +- +- +- +- +- +- +

Is the connecting batteries correct? I mean they are designed correctly?

SO, if they were so, where is the pole/terminal of - and +?

I means let's say my device had polarity so where should I put the negative and positive?

Should I put the negative wire on the very very first sign (which is -) and the positive at the very very last sign (which is +)?

THANKS A LOT FOR UNDERSTANDING MY QUESTIONS EVEN IT IS SO
NONSENSE!

HAVE A GREAT day!

2. ### SgtWookie Expert

Jul 17, 2007
22,194
1,761
If you connect eight 1.5v batteries in series, you will have 12v potential across the battery bank.

No. AA batteries have a very small mAh capacity compared to "wet cells", like SLA batteries.

AA dry cell batteries are rated in mAh's, or milliamp-hours. A typical alkaline cell might be rated for 2500mAh to 2800mAh. The cells are tested using a constant load over a 20 hour period, and are considered exhausted (used up) when their voltage falls below a threshold value.

2800mAh / 20 = a 140mA load for 20 hours.

NiMH and NiCD rechargeable batteries have lower mAh ratings than alkaline cells do.

lead-acid "wet" cells are typically rated for AH instead of mAh.

The batteries are designed correctly. Your series connections are correct.

On the far left side you have the bottom negative terminal, and on the far right side you have the top positive terminal. If you measured the voltage from - to + you would see +12v.

Yes.

Lightfire likes this.
3. ### Lightfire Thread Starter Well-Known Member

Oct 5, 2010
690
21
I can't understand the mAh and AH. What is that?

Anyway, if I will try to power the halogen lamp into 8 1.5 volts connect batteries, it will power even though in a little time???

Thank you again!

4. ### Wendy Moderator

Mar 24, 2008
20,993
2,731
mill = 1/1000

AH = Amp Hours

There is something else about batteries, they have the equivalent of a resistor inside. It isn't real, but the math is the same. This limits the total amount of current you can pull out of a battery, lead acid batteries have a smaller internal resistance.

Apr 5, 2008
16,990
2,969
6. ### Lightfire Thread Starter Well-Known Member

Oct 5, 2010
690
21
OK!

What is the difference between AA, AAA, D, C types of batteries? They are just the same voltage. OR it means the bigger battery, the more lifetime it had???

Sep 7, 2009
2,803
595
8. ### Audioguru AAC Fanatic!

Dec 20, 2007
9,418
903
50W at 12V is a current of 50/12= 4.2A which is far too much current for small AA cells.
Look at the datasheet for an Energizer or Duracell AA alkaline battery cell on their websites to see that a brand new AA cell is 1.5V when new and its voltage drops to 1.0V in about 50 minutes and might produce 4.2A for maybe 3 minutes but then your light bulb will be very dim with only 8V.

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