*This question is for Al Skierkiewicz, Hugh Meyer, Ken Streeter, Doc Wu, or anyone else out there who has access to a West Mountain CBA battery tester and knows how to use it: have you ever used the CBA to test automotive batteries? Do you still have test results you could share?
Here’s why I’m asking. A friend has a 2015 step truck with a big Ford engine in it and a Motorcraft BXT 65-750 battery. This spring he tried to start it, and the battery was dead. He brought it to me and I checked the electrolyte level and specific gravity. Added some distilled water to the cells and put a 3 amp slow charger with auto float on it and left it in the garage charging for 10 days. To my surprise it seems to have taken the charge. It passes a 100-amp 10-second voltage drop test, and for the past three hours it’s been powering a 3 amp load, and the voltage with the load in place is 12.5 volts.
Problem is, I cannot find any discharge curves for this model battery. I fact, I haven’t been able to find discharge curves for any similar auto battery.
So I was wondering (and hoping) you guys might have some data that would tell me if 12.5 volts after sustaining a 3 amp load for 3 hours and 15 minutes is good, bad, or inconclusive.