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

I always look at things for their value. This is a good device for the price. In my opinion the quality is good and slightly better than what I expected at this price point. I opened it up and was pleased to see the heat shield on the wires and near the circuit board (used for a 10 or 15 second timer that buzzes). The connections looked solid and I tightened a few more of them. The clamps and cables are quite good and flexible. Even before I used it, I connected a small 12V fan (like in a PC). It blows on the pile of coal and this helps it dissipate the heat much faster. I hooked it up to a battery and pulled 400 amps for 15 seconds and ran it about 4-5 times in a row and it got hot, but later I took it apart and saw no burn marks or signs of overheating. As I drew 400 amps, I noticed that I could get up to 400 amps, then the reading would slowly drop lower as the heat increased resistance in the carbon pile and joints. So in 15 seconds it can go from 400 to 350 or so. When I pulled 300 amps through, the sensor was pretty stable. So the connections seem correct for 300 amps, but you're pushing it to 400 amps (but I don't think you really need more than that). Finally I set the analog voltmeter. Most people set them up by setting them to zero when you don't have anything plugged in, but I don't think that's the best way to do it and it's often inaccurate. I think your best bet is to apply the voltage that matters most to you and then adjust to accurately measure that voltage. So I used a regulated power supply to put 9.6 volts in (you could probably use a 9 volt battery too) then I increased the reading by 0.4 volts so it reads exactly 9.6 volts. The sensor was perfectly zeroed before alignment, now it reads 0.4v with no connections, but now it works at 9.6v and 12.6v. For this reason I only adjust them with the actual connected voltage. The ammeter is accurate enough in my opinion, it read 50 amps when my clamps read 55 and read 400 when my clamps read 425. Again, I don't think you need excessive current accuracy. I think an analog gauge, even on an expensive model, would be about as accurate. Most of the stuff inside looks repairable if you ever need to fix it and yes I would probably buy it again if I had to.