You describe an old MANUAL charger without timer. They are not allowed to be sold anymore in too many states.
For shorter excursions, a smart battery charger will wheeze out just enough power to limp by. For top charging or restoring a full charge, they are as useless as **** on a boar hog. Try to opt for a pay-for added guarantee on a smart charger. Then all you will be stuck for is the shipping costs when it ignites or plays dead.
Chargers that do not have a built-in timer are extremely stupid. And anything that claims to be automatic or smart is NOT a battery charger -- it is a Tickle Me Elmo grade joke.
