A big advantage for me is the dna 40 board hits the Ni coil with high watts to bring it up to temp fast, then backs down to your set watts or lower is need be.
For the OP http://www.evolvapor.com/datasheet/dna40.pdf
Battery:
A single cell rechargeable lithium chemistry battery is recommended. Either a lithium ion or a
lithium polymer type can be used. Any battery used should be rated for a MINIMUM of 16 amps
continuous discharge current. High C rated lithium polymer or IMR cylindrical cells are strongly
preferred. Make sure that all contacts and connections are capable of handling at least 16 amps.
