Not knowing what type of charging you require, most any brand name multiphase microprocessor controlled unit should do the trick. We have one of the B&D 40 amp chargers from back in the day, which has been wonderful at bringing back to life batteries that have seen better days. I can't imagine they had any advanced technology that today's chargers couldn't duplicate or replicate. No reason you couldn't get a PD or other unit from the links above, we have a 55 amp Iota IQ4 that does a marvelous job keeping our rig's battery bank happy.