This circuit is from a 1967 publication. It is possible to power a fluorescent lamp from a 12 V battery. The unijunction can be 2N2646, SCR or TIC106 and diode 1N4004. T1 is wound in a laminated core and L1 has approximately 30 turns of wire 26. The other winding can be done with AWG 28 to 30 wire.