Battery voltages/percentages

Brianellul Solar Expert Posts: 95 ✭✭

Where can I find a graph or table displaying battery voltages versus capacity remaining percentages such as

12.7v - 100%
?v - 90%
?v - 80v



  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Battery voltages/percentages


    In deference to Trojan’s position as a long-established and leading battery manufacturer, I’m partial to their SOC vs. voltage table for their flooded-cell batteries, which is available here.

    Note that there are other tables floating around. Here’s another example (scan fairly far down). And, Bill Darden, perhaps the on-line battery guru, offers this table. Note that Darden does acknowledge that open circuit values vary by plate chemistry.

    For AGM batteries, here’s a link to another Darden reference, as well as to one from Deka (see page #13).

    You’ll have to decide which one makes sense for your application and battery manufacturer. Note that these values are “open circuit voltages”, or OCV. They’re taken after the battery has been removed from all charging sources and loads and allowed to “rest" for at least three hours and perhaps as long as 24 hours.

    These values do not apply to batteries under load, in which case the values will always be lower than the resting OCV.

    Jim / crewzer