No transformer needed. The 3 Volt Lithium watch style battery can replaced (#HW2300) and each will last up to 80 hours. Plan them for a spot you can easily reach to flip the switch on and off.
LED Dollhouse Lights
6 Arm Renaissance Crystal Chandelier LED
Reported Stock: 3
Vendor: Aztec MiniaturesModel: HW2361
$295.95LED 3-Arm Frosted Down Tulip Shade Chandelier
Reported Stock: 6
Vendor: Aztec MiniaturesModel: HW2321
$48.95LED Fancy Clear Ceiling Lamp w/ Ribbed Plastic Shade
Reported Stock: 3
Vendor: Aztec MiniaturesModel: HW2336
$24.95LED Large Frosted Glass Tulip Ceiling Lamp
Reported Stock: 10
Vendor: Aztec MiniaturesModel: HW2312
$24.95LED Modern Hanging Lamp w/ Plastic Cone Shade
Reported Stock: 7
Vendor: Aztec MiniaturesModel: HW2317
$24.95LED Old Fashioned Oil Lamp Copper Finish
Reported Stock: 10
Vendor: Aztec MiniaturesModel: HW2342
$35.95