I have one of these: http://www.hollyhockbatteries.com.au/CX4000PRO.html Rated voltages are: 3.6v and 7.2v for lithium batteries 1200mA max. charge current I use it to charge the battery only. Although its not 4.2v, would it still be suitable, if I hook the +'s and -'s from the charger to the points you specified?