That will control I/C's as far back as the Heart Interface inverter and even some Trace units IIRC.. Yes there are a fair number of these that have not gone buggy. Problem is most owners don't ever know when they do.... I had one earlier this summer off by .4A. Does not sound like much but that counting error ads up quickly... They are also not always off by the same amount from load to charge which makes it even weirder.