Power Supply

[BrianG]

That ofna one doesn't look bad at all for under $100. 14.5v @ 18A can power a charger with a 200w limit (assuming 80% charger efficiency).

If you don't mind the inefficiency of a linear PS for home use (would be HEAVY to lug around), you might be able to pick up a strong transformer rated for ~20v @ 30A, regulator, several pass transistors, caps, rectifier, heatsink, case, and a few other components for around $50-$80. Should be able to build a PS capable of ~400w.