In article , Richard Lane wrote:
I have 2x SRM27 (85Ah) flooded batteries approximately 5 yrs old on my
sailboat. I wish to test their remaining Ah capacity by applying a fixed
current load and monitoring the terminal voltage over time.
Question: I believe the Interstate table of voltage vs state of charge
is open circuit voltage, if this is true then I would have to interrupt
the discharge periodically in order to measure the o/c voltage then
resume the load until I have achieved 1/2 remaining Ah.
Does anyone have a more direct test of remaining Ah capacity?
Dick

Just keep watch of voltage under load. Forget open cell.

greg