40 years ago at 16 I got a Schumacher battery charger. Worked great until a few years ago and it went into the dumpster. Sparks are bad in a battery charger. I needed a new tender charger and went with Schumacher, it either worked a day and then died and or didn't work out of the box.
Some research and got a well-reviewed Chinese brand, that has worked well for charging and tending, great big digital display.
For some reason I also got a Noco Genius 5, don't remember why, at the same time. Though a limited experience pool, it has to be one of the best you can buy. I have drained 2 batteries down to 6+ volts and both of them have been brought back to life with the Noco. The Chinese one above failed after a few hours on both batteries, got a "batt" on the display but the Noco revived them, miraculously.
Highly recommended.
