Making an ugly, portable battery diagnostics jig
0My design philosophy: "Decide that I want something, RIGHT NOW, and then build it on the spot and make it up as I go along". This entire build/design took about four hours.
This thing is essentially a portable 12 A battery charger and 12 A dummy load for 6-cell lead-acid batteries. Its purpose is to allow me to get an idea about the condition of scrap batteries before I bring them home for reconditioning. It will allow me to assess a few things;
The OCV (state of charge) of a battery,
the voltage under load (indicator of internal resistance), and
the battery's ability to accept charge (indicator of internal resistance and possible sulfation, as well as a dead give-away of shorted cells, if the OCV drops below 12 V after a short charge)
So, I'll be able to get a rough idea about how the battery has been treated during its lifetime, and most importantly, after it's been taken off-duty; a battery that's been sitting for so long that its OCV is much below 12 V (weeks to months), will probably have some serious sulfation.