Depends on which one, but many of the new ones don't necessarily have any kind of float or trickle mode. That supposedly can slowly damage batteries. What they have is a maintain mode, where it stops charging when full, monitors the voltage, and then starts charging again when it drops below a certain voltage.
I bought a Schumacher SC-1200A/CA (may be discontinued) over 7 years ago and it's the one I can still find since all the other ones I've got seem to have disappeared. I like the LED display, which outputs the voltage when not in charge/maintain mode and then flashes between 12 (I guess meaning 12V battery seen) and an estimated charge percentage until the display eventually goes dark (starts displaying again with any button press). It's a 3A/12A with a select button for 3A/12A and another for standard or AGM. At 12A it charges until fully charged and then goes into maintain mode where it will only charge at 3A. It is kind of weird with a dead battery because it seems to think that 7V means that it's a fully charged 6V battery.
I looked it up i my Amazon order history, and it was $30.52 back in 2013. Can't find anything quite like it for the same price, but this one is the closest at more than $50. It doesn't seem to have buttons per se, but looks like a key for rate selection and battery type, plus a dedicated start/stop as membrane keys (not sure if I like that idea because I've seen that looks like at gas pumps).
I bought a Schumacher SC-1200A/CA (may be discontinued) over 7 years ago and it's the one I can still find since all the other ones I've got seem to have disappeared. I like the LED display, which outputs the voltage when not in charge/maintain mode and then flashes between 12 (I guess meaning 12V battery seen) and an estimated charge percentage until the display eventually goes dark (starts displaying again with any button press). It's a 3A/12A with a select button for 3A/12A and another for standard or AGM. At 12A it charges until fully charged and then goes into maintain mode where it will only charge at 3A. It is kind of weird with a dead battery because it seems to think that 7V means that it's a fully charged 6V battery.
I looked it up i my Amazon order history, and it was $30.52 back in 2013. Can't find anything quite like it for the same price, but this one is the closest at more than $50. It doesn't seem to have buttons per se, but looks like a key for rate selection and battery type, plus a dedicated start/stop as membrane keys (not sure if I like that idea because I've seen that looks like at gas pumps).