Im a DIY guy. And i could easily go out and buy one of these. But, i am very interested in creating one. So i am set out to creat a bettery powered battery charger. now i need some help, this is what im going to do,and if im wrong or missed somehting please tell me.

I am going to get Brand new D batteries, and Old Double A batteries that don't work (rechargeable obviously) i am going to get a piece of 2x4x1ft and im going to notch a little spot for the double A batteries. IM going to buy mini alligator clips and thread some wire through it then connect the alligator lips to the D and double A batteries, but before that, i am going to drill a hole, about 1 inch big. into the 2x4, twice, big enough to go on both sides of the battery, i am going to put the gator clips through there, then attach them to the battery as well as i can, i am going to get a volt meter and measure every now and then. is this 1 safe. or 2 will it work?

You are "barking up the wrong tree". It would work, but why but batteries to recharge batteries? It gains you very little as opposed to using a transformer type power supply to do the charging. Better yet, just go out and buy a battery charger and be done with it. In the long run, you save money, and most of all time. While I understand your desire to "DIY", but the practicality of the project just is not there. You are trying to save money, but will only end up spending a lot more in the process. Go out and buy the manufactured charger, and use your intellect for something else that is more worth while.