IF YOU RUIN THE LAMP, IT IS NOT MY FAULT. THIS IS AN EDUCATIONAL HOW-TO PROJECT FOR THE SAKE OF THE LAMP.
Step 1: Materials...
Ikea Solar Table Lamp ( I bought at Ikea)
5v Small Transformer (was a cell phone charger...)
22 Ω Resistor ( RED RED BLACK ) It is okay to use this resistor. It won't ruin anything.
Diode (found in common electronics! 1 amp diode will do!)
Drill (to make hole for wire to come out to transformer)
Step 2: Start
Take apart the base of the Solar Lamp and take the two screws out of the connectors plate.
Solder the 22 ohm resistor to the positive side of the connector. Then the adapters positive wire to the 22 ohm resistor.
Solder the negative side of the adapter to the negative side of the connector plate.
Jam it all in the plastic case thing. MAKE SURE you don't have anything touching that should not be touching.
Put the connector plate together to the dark base. Don't completely put it together yet.
Add the diode coming from the circuit board, to the connector. (See photo)
You don't want the 5 volts going into the circuitry.
You're done! Put it back together carefully.