I'm getting ready to possibly replace all three batteries in my Power Wagon, and that prompted a call today to Northstar. Found out that they are planning to introduce Bluetooth-enabled batteries at SEMA in November. Batteries will allow you to monitor state of charge in real time on your phone, and also to monitor and evaluate your charging system while in use. They have tested the system with Apple's somewhat proprietary Bluetooth system and say it works just fine. Probably overkill on a single-battery truck, but a great idea for a setup like mine with three batteries to worry about. But I may not be able to wait that long.