LED assistance desired, Just a little project Options

[Bigmeanbulldog55]

I'm doing a little project for my Animal Training class and I'm having some problems with my LED set up. I've got some regular Radio Shack brand LEDs, model 276-1622. The power source is 4 AAA batteries putting out about 6.4 volts (volt meter measured). I'm only lighting one LED at a time with the 6.4 volts. I've done this twice now. The light flashes and then won't light again. Am I really blowing these things with little little voltage? I don't understand because I had some hooked up in my car running the 13-14 volts between the 2, and they worked just fine. They were a different brand though. What do I need to make this work?

[Bigmeanbulldog55]

I've ditched the 4 AAA, and opted for a set up with one AA battery per LED. Do you think that will work? I'm going to try it on an LED I don't need first. This isn't the ideal set up for me, but it works for now. If 3v is max, I should be able to get away with 2 AA or 2 AAA batteries per LED. I want them as bright as I can get them. I guess I'm newer to LEDs than I thought I was.