Not only is it not a manual charger, it's apparently not a very intelligent smart charger. The reviews are not encouraging. Harbor Freight has some reasonably decent stuff and some that isn't, and this appears to be more towards the latter category.
Apparently if the battery voltage starts out too low, it won't turn on based on surmising an incorrect connection. Apparently it doesn't always do very well at switching between charge and maintenance mode (though maybe people were expecting 50A to supply that continually, rather than with the specified duty cycle of 5 seconds on, 4 minutes off). Apparently a fair few are dead out of the box. Apparently also some people find it sufficient for their needs...but I wouldn't chance it myself.
