Review on Onebuy Car Battery Charger 12v 5A: Smart Trickle Charger for Car, Motorcycle, RV, Lawn Mower, Boat, ATV & More by Jon Smith

I ordered another device and connected it to the 12V lawnmower battery. No activity after 24 hours. After 48 hours I unhooked it and sent it back. I thought maybe the battery was dead, but I decided to give this device a try before spending $50 on a new battery. At first nothing happened. After a few minutes of plugging it in, it indicated that the battery was charging. I went to work the next morning with the device still in charging mode. When I got home, charging was complete. After 5 days I put the battery back in the mower and it read 12.7 volts. I also had a low battery that wouldn't start the engine in a car that sits a lot, so I plugged it in overnight and the car started right away. The device appears to be working well and has great readings telling you what's going on and how much charge is in the battery you're working with.