You can use the more powerful YTX20CH replacement the HJTX20CH-Firepower WPS Lithium Battery its the same size as the OEM Yuasa...
I don't get why they're doing this in the first place:
use all the avail space to give you actual reserves instead of "hey, we're producing it in 1/3rd of the size to barely meet your original capacity..."
Over here we've real winters, hence being grounded for a couple of months can occur... during which a conventional battery frequently dies/eats itself if left unattended...
I would go the Li-Io route if those would survive up to 3~4 months in the garage... (and all the safety issues are fixed...)
On the larger scale I think we're getting fooled and shortchanged by lobbyists and industry...
Back in the 90ies my ST batteries would easily lasted 5~6 years (car batteries ~10 years)...
Now with all the RoHS
everything must be low toxic directives, one rates himself lucky to see 2 years of any automotive battery...
and I fail to see how this increased circle of
mining<>production<>waste should be environmental friendlier in at all... (except keeping shareholders happy...)
So besides a significantly larger capacity, I'd also like to see a
noticeable increased lifetime on those Li-Io batteries, especially over the problematic mining of rare ores involved...