I'd say the rate advised by the manufacturer in the data sheet
** Just a tad less than that required to blow the internal fuse.
Do SLA batterys usually have an internal fuse?
I'v never seen any mention of one in manufacturer's literature.
I have seen the aftermath of people short circuiting large gelcell/AGM
batterys and heard storys of other incidents. This is almost allways
due to people using an uninsulated spanner and rotating it so it
touchs another battery terminal or the chassis, although ocasionally
people put a link lead on the wrong terminal.
I'v never heard of a battery fusing, if the short is cleared after a
few
seconds the batterys works afterwards.
In my experiance the off-load off-charge voltage of a
charged SLA battery only gives a meaningfull indication
when the battery is near the end of it's life.
When the battery has only a fraction of it's capacity left,
in the region 10% of the original AH rating,
the voltage drops quickly off charge,
eg if a nominal 12volt battery is at 12.5V instead of 13.5 straight
after being taken off charge it probably has significantly reduced
capacity and will probably be useless within a year.
Bob
