Ducky's Dad
Explorer
Another option would be something like a Ctek 7002 at 8 amps. I have one and it does a very good job on my retired Optima Yellows, now just sitting in storage as emergency backups. I don't know if, by itself, it will work on batteries down to 2.5V as the Odyssey says it will. I do know that the Ctek brought back two or three Yellows that had been sitting outside for a couple of years. This Ctek is very compact and can be had as a refurb for around $85. Good value.