Around 2017m05d22 I pulled a 12V SLA battery from a trailer. The SLA was being used to power the emergency braking system for the trailer. I did not know how old the battery was or when it was last charged. Here is a photo of the battery.
My DMM measured 6.3V across the SLA. My experience says this means the battery is near death and cannot be restored. I chose to mess with it anyway. I put the battery on a 14.3V / 2A charger and measured a voltage of 13.9V. This usually means the battery is not accepting charge and is presenting a high impedance to the charger. I left the charger connected overnite. The next day the voltage was still 13.9V. I disconnected the charger and the voltage was 12.2V ...... this was a surprise. I do not yet have an explanation for it.
I shorted the SLA with a spoon for 2 seconds and got a big spark and some glowing metal. Afterward the voltage was still 12.2V. With the charger connected the voltage was now 13V.
I will continue to monitor this battery.
Gus in Denver
tags: 99guspuppet 777SLA 777restoreSLA