20 amp.. That's not a fast charge, Even for a Group 24 that is not a fast charge. (in fact for a group 24 is it very close to the recommended charge rate)
Anything bigger well the bigger the battery the slower the charge as it were.
20 amps for a decent house battery system is approaching a trickle charge.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times