Well yesterday Sat Aug 16 2014, I dug out an inverter and hooked it up it didn't work at first. After opening it up I noticed it had a couple of loose connections and what looked to me like a 94 pin computer chip was half out of its socket Pushing it back in place the inverter went to working
the bank was only at 12.34v after resting all night
I tried various electric heaters but the inverter would go into low input voltage warning and shut off
So I thought of an electric hot plate with its variable heat control
At the full setting the bank showed 11.7v then the inverter would shut off.
I finally got the hot plate adjusted where the bank voltage showed 12.1 and left it there in just a few seconds the heat on the plate was above 700°f after a few minutes the coil was starting to glow a dull red
After 15 minutes the voltage dropped to 11.8 I turned the plate setting down until the voltage was back up to 12,1 . Another 5 minutes I had t adjust it again until after a toal of 30 minutes the pate was down to 600°f the voltage was down to 11.6 .At which time the inverter shut down again
With the inverter off the bank showed 11.9v I put both of the Wanco chargers on parallel on and after about 2 Hrs the the while charging voltage had reached 13.6 the at rest voltage was 12.6 after 10 hrs inverter on standby the voltage is still 12.2
I will charge and discharge again sometime today.
You can just barely see the left sodium tube start to turn color a lot of my testing is using the benswag method (best educated non scientific wild A**guess)