The lights charge via USB cable.
Step 1: Get Lights
It is Important that when you purchase lights they need to be:
1. Led lights not incandescent!
2. Battery or solar powered (mine were solar powered and the sun charged a ni-cd battery
Step 2: Modify Lights
Cut off string of lights and save. If you want to save the solar charger part you can, I used the solar part for parts.
Step 3: Then Solder Plugs and Jacks
Then strip wires from light string and solder to jack, you can use any dc jack as long as you have a male and a female to go to gather. As you can see in the picture I soldered the LEDs to the jack. In the next step you will see what the other two wires connected to the jack are for.
Step 4: Connect Plug to Lights
The other wire to the small jack goes to this jack.
Step 5: Connect Rechargeable Battery Pack
Then install 3 rechargeable battery's into the holder and notice the large jack on the side of the holder, that is where the male jack going to the string will plug in.
Step 6: Make and Connect USB Cable
The USB cable I used has a USB plug on 1 end and a small male plug on the other end. I could not find a USB cable like this so I went to RadioShack and bought a small male jack and I cut off the end of an old USB cable and soldered a wire between the USB cable and the plug, then hot glued the the wire to the USB cable, I did solder the connections but the wire from the USB cable was smaller than the wire I used so I got glued it just for strength.
Step 7: Connect USB Cable
Now connect the USB cable to a phone charger or any USB port that can supply power that can supply at least 700 mA. Then connect the other end to the small jack on the led light string. Then plug in the USB cable.
Step 8: Test It!
Plug in the USB plug into a USB port and the lights should go off then after about 1 hour of charging unplug the cable from the string of lights ONCE UNPLUGGED the lights should THEN come on. The jack is wired so the lights will come on when unplugged and the lights will stay off when the charging plug is plugged in. If it doesn't work try soldering all connections and make sure it is wired as in the pictures. Enjoy!