Yuasa website lists a charging current of 1.6A for the YB16AL-A2, and also provides some useful information regarding the 'do's and dont's' for recovering discharged batteries. The following is not recommended......
I bought a CTEK MXS 5.0 some years ago, fully automatic with several options including a small battery setting (with motorcycle icon). Eight charging stages, desulphidation, soft start (0.8A until 12.6V), bulk charge (increasing voltage to 14.4V, 0.8A), absorption (14.4V, declining current), analyse (checks if voltage drops to 12V), float (13.6V, 0.8A), pulse (12.7V-14.4V, 0.8-0.4A). Also a recondition mode (max 15.8V, 1.5A). Also able to charge car batteries at up to 5A, and the one I have works on 12v lead acid batteries (wet, MF, Ca/Ca, AGM and GEL). Just connect to the battery and let it do it’s magic. With the connectors supplied, easy to put the bike on charge every couple of weeks over winter to keep the battery in tip top condition. Brilliant bit of kit, perhaps you can find one on eBay!
12.6 this morning after an overnight charge on the low setting of the 4ah car charger. Left it off charge until I get home from work and will check it again.
Someone said that to me around twenty plus years when we constructed a surface mounted swimming pool & by not reading the manual we got one or two things wrong but we'd correct them in the end.
I have an Optimate II, it doesn’t seem to do anything if the battery is below about 10.5V. I bought a cheap standard battery charger for that situation, about half an hour on that then the optimate seems to work.
What about the shoe bomber and that cvnt with the exploding underpants. That didn’t explode. Just burst into flames. Maybe there is a God??