P30LF percent charged readout seems to be way-way off

Discussion in 'Charge Controllers' started by J Stanley, Mar 14, 2022.

  1. P30LF, Trojan t-105 (4). Controller settings entered direct from data sheet for the various required numbers (float, 13.5V, bulk charge 14.8V, equalize 16.2V which is not a possible setting). For equalize, I used the highest setting that was allowed. As I recall that was something just over 15V.

    SOC from data sheet is 100% @ 12.8V, 80% @ 12.5V, 60% @ 12.25V, 50% @ 12.1V. The P30LF says the SOC is 50 to 60% @ ~~ 12.6V, and triggers bulk charge.

    This does not seem to be remotely correct. Normally, the float charge is about right, at 13.5 to 13.6V. But the controller State Of Charge curve seems to be totally bogus. It starts with 90% remaining up at over 13V.

    I assume the battery voltage settings are used in some way to derive the assumed SOC curve. Since the equalize voltage from the data sheet of the battery is beyond what the P30LF settings even allow, perhaps that is fouling up the arithmetic to derive the curve.

    Whatever the reason, the SOC readout is completely wrong. I do not know whether this is due to an original programming error or due to some defect in the nit itself.

    Should the P30LF be expected to have the SOC curve so far wrong for a very standard deep cycle lead-acid battery?
    Last edited: Mar 14, 2022

Share This Page