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    • TriMetric confusion

    Solar Expert Posts: 39 ✭
    in General Solar Power Topics #1
    Howdy. I just installed the TriMetric and am trying to enter the setpoints. The manual says to use 28.6 for the charged setpoint voltage. I have 12 Trojans L16RE-2V in a 24 volt system. The battery is rated at 1235 AH @100hr and 1110 AH @20 hr. I don't understand their instructions for calculating the battery system capacity. My batteries are connected in series. Please help me with the math. Thanks a lot!
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    • Super Moderators, Administrators Posts: 33,671 admin
      #2
      Re: TriMetric confusion

      Correction: The below I made a mistake and thought the OP had 24x2 volt batteries... Not 12x--The stuff following is correct in principle--but for the original question, the OP should enter in 1,110 AH (20 Hour rate) because there is just one string of 12 batteries. -Bill B.

      L16re-2v 1110 @ 20 Hour Rate.
      • 12 batteries * 2 volts = 24 volts @ 1,110 AH per string
      • 2 strings at 24 volts * 1,110 AH = 24 volts @ 2,220 AH
      Adding batteries in series increases the voltage.

      Adding batteries in parallel adds the AH capacity.

      There is no loss if power/energy if you have a 12 volt bank at 4,440 Amp*Hours or a 24 volt at 2,220 AH.
      • Power = Volts * Current
      • Power = 2*volts * current = volts * 2*Current
      Is that the question?

      -Bill
      Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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    • Solar Expert Posts: 1,485 ✭✭✭✭
      #3
      Re: TriMetric confusion

      The 28.6v setting is just the voltage trigger that the Trimetrics resets the battery to 100% full. That is a good number as your absorb charge setting should be at least 28.6 vdc.

      The AH setting is just the reference for the AH count up/down. You can play whatever psychological games you want on this setting by setting the reference number to 50% to 80% of you batteries AH rating.

      I have mine set to 50% of 20 hr. AH rating to encourage me not to discharge batteries below 50% SOC.
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    • Solar Expert Posts: 386 ✭✭✭
      #4
      Re: TriMetric confusion
      he battery is rated at 1235 AH @100hr and 1110 AH @20 hr
      Use the 20 hour rate: 1110 AH @20 hr on the Trimetric. Set the charged set-point current around 20 amps and the charged set-point voltage around 29 volts. This is used by the Trimetric to determine when the battery is fully charged.
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    • Super Moderators, Administrators Posts: 33,671 admin
      #5
      Re: TriMetric confusion

      MikeO,

      You are suggesting 1,110 AH setting to show 0-100% capacity based on 50% maximum discharge for long battery life?--Or did I mess up reading the original question?

      -Bill
      Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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    • Solar Expert Posts: 39 ✭
      #6
      Re: TriMetric confusion

      I'm sorry, this is a struggle for me. So, is the number I program for the battery system capacity gonna be simply the AH number, which is 1235?
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    • Solar Expert Posts: 386 ✭✭✭
      #7
      Re: TriMetric confusion
      which is 1235?
      No use the 20 hour rate for you battery capacity which is 1110 amp hours. Bill I am suggesting just putting in the new battery capacity rating so when the Trimetric reads 50% full on battery capacity, you know its time to get it charged up again. The Trimetric also has an amp-hours from full reading which would correctly read -555 amp-hours at 50% DOD.
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    • Super Moderators, Administrators Posts: 33,671 admin
      #8
      Re: TriMetric confusion

      Opps--I did miss-read the post... It is 12 batteries--Not the 24 I thought I saw.

      Fixed original link.


      Thank you Mike.

      -Bill
      Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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    • Solar Expert Posts: 39 ✭
      #9
      Re: TriMetric confusion

      Okay, thanks for the help folks. My P1 is 28.6, P2 is 22.2, P3 is 1.11(decimal is flashing which means 1,110). Do I have it right?
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    • Solar Expert Posts: 39 ✭
      #10
      Re: TriMetric confusion

      I can't get P2 to be 22.2. It won't do the .2. All it will do is 22. Is that okay?
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