That is not uncommon. When you charge a lead acid battery you form hydrogen and oxygen (that's what causes them to explode) it bubbles off the plates in the acid solution and that's what you heard. The faster the charge rate (more current) the more bubbles you produce, I would guess that you were charging it at a rate of 5 amps or more. Regards, Mike D. --- In dmcnews@xxxx, theshovel1224@xxxx wrote: > Had my battery on the charger for about 8 hours today. When I > took it off the charger, I heard a bubbling sound coming from > the inside of the battery. Just wondering, does a charging battery > normally make a bubbling sound after awhile? > > John Yeoman