How can I calculate maximum "healthy" amp draw on a battery bank?

[SolarWatt]

What is the definition to 100% DoD ??

[SolarWatt]

I should explain myself better:
I want to determine the Peukert coefficient of my battery.
For that I need to know the time for 100% DoD in two different discharge rates.
One I know, 20 Hours at 3.5A (Because it is 70A-H battery)
Now I Discharge at rate of 7A and measure the time it takes to reach 100% DoD.
But how I know I reached 100% DoD ??

I am using the formulas at: http://www.smartgauge.co.uk/peukert_depth.html

Thanks
Elad.

[Sunking]

When under any load you reach 1.75 volts per cell or 10.5 volts for a 12 volt battery.

FWIW a rested 12 volt battery will measure 11.8 volts

[SolarWatt]

When under any load you reach 1.75 volts per cell or 10.5 volts for a 12 volt battery.

FWIW a rested 12 volt battery will measure 11.8 volts

Thanks