Review on Battery Monitor BM2 BM3 Bluetooth 4.0 Wireless Battery Tester for 12V Automotive Battery Load Testing, 🔋 Monitoring Automotive Charging Systems, and Cranking Analysis. A Digital Battery Analyzer Applicable for Android & IOS Devices by Dave Calabro

I installed the app while waiting for the device to arrive. When it arrived and I installed it, it was immediately found via bluetooth. Installation was very easy, it took me longer to go outside and get the key from the trunk than to physically install it. My positive terminal cover doesn't quite fit, but can be secured with a small slot in it. After plugging it in it told me my battery was at 9%, somewhere around 12v. I ran the machine for about 20 minutes and got it up to 90% (14.3v) but as soon as I turned it off it started Autumn. After 8 hours my battery is at 68% (12.39V). I will check the battery purchase date. Maybe it needs to be replaced. It's better than waking up at 5am, going out in the rain and finding your car dead because it hasn't started in 5 days. I was lucky that a neighbor jumped on me, but the battery should hold a charge even after 5 days of idling. I am planning to get another present for a friend.