Charging batterys inline??

I am making a LED hula Hoop for my GF for her Bday.
It is pretty simple just 18 leds hooked up to 2 x AA batterys in series to get 3 volts.
I want to put some sort of a plug so she doesnt have to take the hoop apart when the batteries die??
How can i charge the batteries while they are in the hoop?

I have very limited experience working with circuits and such.. so please keep it simple. Thanks for your time. I will post the finished product when i am finished.

If this helps...
I am loosely baseing my hoop idea on this
LED Hula Hoop

so yah i just want to be able to charge the battery's in the hoop.

The battery is 3V when new. Some bright green and blue LEDs need 3.5V so they won't light.
The battery voltage quickly drops to 2.4V and the red LED will become dim.
The battery voltage continues to drop and the remaining red and orange LEDs will get dimmer and dimmer.

Okay .. well i 'll use different resistors and put a couple 9 volts or 4 AA's to make 6 volts... Back to the question,
how can i charge them while they are in the hoop?

dog812 said:

Back to the question, how can i charge them while they are in the hoop?

Click to expand...

You slap a couple of magnets on either side of your girfriend's torso. Then, use some coils with larger wire so the current gets bigger. As she swivels her hips with the hula hoop, she'll induce, gee-whiz, something I'd imagine into the coils, perhaps into everyone who's watchin'... I forgot, where was I?

If you'd keep up on the alternative energy forums you'd know...

Sorry i thought I explained it but I dont mean charging them while shes hooping..
I mean after shes done.. what can i use to plug it in or something?

Connecting more batteries and a 9v battery even make the hoop unbalanced.

dog812 said:

I have very limited experience working with circuits and such.. so please keep it simple. Thanks for your time. I will post the finished product when i am finished.

Click to expand...

Please post a video of your GF's hula hooping