Rechargable Battery Facts?

I have many surefire, streamlights and a g2 with a p60 drop in from DX that take 123 lithium batteries. I also have a few that run on D's A's and AAA's. I have been reading at CPF for a while and just joined. My question is are there any good resources to find out about rechargeable batteries. Not to sound like a novice, but I am. Are rechargeable AA, AAA, D all 1.5 volts like an alkaline? Does the "mah" play a big deal in amount of brightness or run time? What is a protected circuit? Are the rechargeable 123 batteries any good and do they have a better run time? What type of charger to buy for what type of batteries? I looked for answers, but you guys already know what you are talking about and I am a little confused. Maybe if you guys know of a link that has the basics in it for me. Thanks for any info, just trying to learn.

Hello Rbramski,

Welcome to CPF.

You need to spend a little time reviewing the material at www.batteryuniversity.com and then you should have an idea of the overall picture.

Tom