The stock Dolphin charger has always gotten a bad rap. Mostly because it's not well understood. I've done more research on chargers than anyone else. This experience goes into this now , very solid, product. They are well tested. If you find that your 12v aux battery is not at 13.5v-14.3v then you may have a dc-dc board issue. Don't forget if you want a higher or lower voltage output from your charger, then you should also purchase a Charger Software Mod for your Main Board.