AA battery pack for backup camera issues

[tonythemediaguy]

Hi,

I'm using one of those cheapo 3.5" backup cameras for a little mini portable I'm working on. I'm trying to work out the power. I'm using 10 rechargeable AA batteries to give the screen a range of 11-14v or so which it works just fine. My issue is when my batteries got down so low, I removed them to charge them up again. 8 of my AA batteries were 1.25v and the other 2 AA batteries were both 0v. My digital charger wouldn't even recognize them, I had to put them in my analog charger overnight to bring them back to life.

So what I'm wondering is why 2 of the 10 batteries were drained so very low and the other ones weren't. I'm using a radioshack 8 AA holder and a 2 AA holder wired in a series. The two AA's that were messed up were right next to each other in the 8 AA holder, where the positive meets the negative from the 2 AA holder.

Hope someone has some insight on this.

Thanks!

[jdmlight]

Are the 2 AA's that were completely drained different in some way? Different brand, older/newer, used more/less, etc? Typically that will happen if those two cells are older/used more. Then, those batteries get discharged more quickly. Because you're using them in series, the "chain is only as strong as its weakest link" adage applies.

[tonythemediaguy]

They are all Duracell nimh 2650mah. Some may be used more than others, but they were all bought at the same time.

I just charged them all up again so I'm going to put them in the holder in a different order to see if that makes any difference. I don't think it will.

What's the most common way of powering these lcd screen in a portable?