A good battery load tester is essential for anyone who tinkers with cars, boats, offroad vehicles and more. Just because your battery shows 12v doesn't necessarily mean it's good to go. Test your car battery under a load to tell for sure. The Harbor Freight Centech battery load tester also can show the status of your car charging system. They cost only $19.99 or less with your coupon.

Harbor Freight 100amp 6v/12v Battery Load Tester:
https://www.harborfreight.com/automot...