If you've been putting too many amps into battery you've probably damaged at least one cell.
Lead acid batteries should never be charged at more than 1/10 of capacity (although initial current can be higher to 'break down' surface resistance, usually for no more than 1/5 ~ 1/3 for 20~30 sec)
If you have a 10A/hr battery 1A will be max charge, smaller battery, smaller charge rate.
Using car charger/quick charge/jump start will at best shorten life and at worst damage battery
It's such a problem Suzuki stopped changing batteries under warranty in 2009~2010 (forget exactly when), dealers were not prepping them properly and they were failing after 3~6 months