battery boil

[madson95]

Hi was walking by my coach yesterday and could hear the battery hissing.pulled the tray out and the first battery was hot and hissing. shut off all switches and pulled the plug on the charger(old orig charger)waited for about 5 min and battery still hissing. i then disconnected the hot leads from the battery and after awhile it stoped hissing this am went back and connected the hot leads, everything else was off and the charger was unpluged. it started up hissing again . disconnect the battery .was wondering if the other batterys could be trying to charge the battery?and if it could be a short in that battery. plan on getting a new charger, (a smart one) so something could be smart. any sug. would be helpful
warren madson
85 40' wide body
vw bug toad
Bandera TX sept to may Calmar IA may to sept