You probably should have mentioned that to use the high voltage method of attempted recovery safely, it is necessary to use some sort of current limiting device. I am guessing that your variable supply had that built in, but not all do.
In the early days of radio, some amateurs would use electrolytic rectifiers made from a strip of sheet aluminum and the carbon rod from a #6 dry cell immersed in a bath of baking soda. The rectifier thus constructed was hooked up directly to the 110 volt ac with a light bulb in series as a current limiter and used to charge batteries. Not exactly CSA/UL approved, and "extremely disagreeable" to have around, according to contemporary accounts. Steve Thomas C&C27 MKIII Port Stanley, ON. ---- Michael Brown via CnC-List <cnc-list@cnc-list.com> wrote: That should be Caustic Soda, not Baking Soda. If a battery in otherwise good shape has self discharged to the point of being flat has a bit of Epsom Salt or such added it might help recover the battery. No magic going on. With a flat battery it is hard to get a current flow started and the cells may not respond equally. A small amount of some metallic salt will allow charging and help with equal charging. I have used a variable power supply to recover a new but flat AGM. They were left uncharged for about 3 years. It required around 30v to get a 0.05 amp charge started, which gradually became 0.1 amps at around 20v after a couple of days. Out of three dead AGM two have recovered and I was able to run a discharge / normal charge test on them. The other AGM only recovered to 10.4v after sitting idle, one cell never charged. Michael Brown Windburn C&C 30-1 _______________________________________________ This list is supported by the generous donations of our members. If you wish to make a contribution to offset our costs, please go to: https://www.paypal.me/stumurray All Contributions are greatly appreciated!
