I have the same tester. Piece of crap. I wrote it off, and just bought the ZKEtech 40amp tester Andy uses at off-grid -garage. Many must be buying them, as the price on Amazon is about $280 now, and shipping from China on Aliexpress is VERY high. I just ended up buying one for about $150 plus shipping today. Screw it. The software alone is worth it, and being able to charge and discharge at 40amps would be kinda nice. Now I just need to see if the 110V version can actually do that, and I may have to run a new outlet just for the tester.