I had misread the original battery crash test article, in the YM April 2008 issue Nigel Calder suggests a 5% load over a 20 hour-ish crash test down to 10.5 volts. I performed a 10 hour test.

The battery is a 140ah Bosch starting its 4th season of use. I applied a 7.3 amp load overnight. After 9 hours 54 minutes the link-10 monitor reported 70 amp hours consumed.

At test end the reported current had dropped to 7.0 amps and voltage under load was 11.53v. After 6 minutes of zero load, voltage recovered to 11.85v. I thought this indicated a healthy battery but the graphs here suggest my battery had lost 95% of its charge compared a theoretical 50%.

http://www.arttec.net/Solar_Mower/4_Electrical/Battery%20Charging.pdf

However this site below indicates that my rest 11.85v volts for an assumed 10 degrees c = around 40% remaining.

http://www.buchanan1.net/lead_acid.shtml

Whereas this Adverc chart below says 12.2v = 50% charge.

http://www.adverc.co.uk/technical/technical-soc.asp

What do you all think, one more season of use left?