Review on 🔋 FJC 45115 500 Amp Carbon Pile Battery Tester: Efficient and Reliable Inspection for Batteries by James Jenkins

For the price - like a decent block. I have not disassembled it, only used it with 3 batteries and have not tested the alternator with it under load, but the voltage and current readings have been verified with my meter and ammeter to be accurate and there was no sign of heat to worry about. but I only drew 200 amps with it, it's an "old school" system. If it starts reading "out of spec" it's easy to adjust as the potentiometers can be clipped from the front of the unit. If it ever fails completely and you know what you're doing it will be very easy to fix - it's a variable resistor ;)