Amazon has the TOPDON AB101 Car Battery Tester for only $21.99 Shipped when you clip the 20% off coupon and use coupon code AB101DEAL at checkout ! (Reg. $40) This has really awesome reviews. This car battery tester is highly recommended by Scotty Kilmer and BestReviews. By directly benchmarking the battery health, this battery analyzer gives advice on whether to replace the battery. Besides, the cranking and charging system tests are also included.
