DIscharge voltage level?

klrskiesklrskies Solar Expert Posts: 30
I've been stopping the discharge from my battery when the battery voltage equals 12.1v, but that's under a load. Is that how to gauge the cut off voltage, or is it the batteries' voltage level after the load is removed, and the battery has stabalized for a while that is used to determine discharge cut off?



  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: DIscharge voltage level?

    Standard disclaimer: Voltage is not an accurate indicator of SOC.

    That said, it would be a bit impractical to disconnect loads, wait a couple of hours, then check resting Voltage to see where it's at or dip the hydrometer in for a SG reading.

    Your 12.1 Volts under load is as good an arbitrary cut-off point as any, and ought to ensure you don't over discharge your battery. Remember that different loads drawing different Amps will bring the Voltage down different amounts; don't be surprised to see the V spring back up when a heavy load is turned off at 12.1. Of course a more powerful battery will withstand the drag of heavier loads better (less V drop).

    For a very accurate on-the-go SOC reading you need a battery monitor.
  • klrskiesklrskies Solar Expert Posts: 30
    Re: DIscharge voltage level?

    Thanks for the response. I've been looking at battery monitors, and they seem like the the ideal way to keep up with battery status...the tri-metric 2025 looks like a good one to consider...around $150 + a shunt. Beats having meters all over bthe place like I have now.
  • icarusicarus Solar Expert Posts: 5,433 ✭✭✭✭
    Re: DIscharge voltage level?

    The Trimetric is a great meter. It I'll give you pretty accurate gauge of SoC.

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