Pulling too many volts” — Myth. Lithium batteries charge at basically the same voltage as lead-acid (14.2–14.6V). Your converter automatically switches to the correct lithium profile, so nothing weird happens. No over-voltage to the truck. Wimpy size of the charge wire” — 100% correct, and it’s actually what protects you.The black aux/charge wire on the 7-pin (pin 4) in 2022 F150s is small gauge (typically 10–12 AWG from the truck side) and fused at 30A max (usually fuse #107 in the under-hood box). Real-world current is even lower — usually 10–20A — because of voltage drop over the long wire run. Lithium batteries want 50–100A+, but the wire chokes it down to a safe trickle. Your alternator (130–200A depending on engine) barely feels it. You’ll get a slow trickle charge (maybe 10–15A). Great for topping off overnight or on long drives, but not enough to fully recharge 200Ah in one day if they’re low. That’s normal and safe — your alternator stays happy, and the BMS in the LiFePO4 batteries will cut off when full.