GW InstekPSP-405 LCD Display Programmable Switching DC Power Supply, 0-40 Volts, 0-5 Amps, 200W

I've used another version for years. This is just as good. Just be careful of hooking up batteries backwards when charging them. It blows a diode inside easily. But its an easy fix.

These are perfect for our standalone test fixtures that require some adjustability and 30+ amps. We have purchased 4 of these.