Discrepency in maximal charging amps

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MichaelK
MichaelK Registered Users Posts: 234 ✭✭✭
in Off Grid Solar & Battery Systems #1
I posted this on the Midnight site, but so far I have not gotten any kind of response.  So, I thought I would ask here about amp limit of my Midnight200 charge controller.

On page 9 of the "DIY Manual" (10-543-1 REV A) I spotted the Current Output Limits chart as indicating that the maximal current output for a 48V system as 78A.

When I bought my Midnight200 controller back in 2017, page 67 of the manual (10-001-1 REV: 1) indicated though that the Absolute Current Output for a 48V battery was 65A.  Since installation, I've had the max amperage set to 65A.

Since I have a 4500W array, I typically see clipping to 65A when running heavy loads, like my 240V well-pump, around noon.

So, the question is why the difference in the two amperage maximums?  Is it a firmware issue?  Currently I'm running firmware version 2193 on my 200s.
System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    #2
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    The maximum output amperage may be a function of state of charge battery voltage and ambient temperature around charge controller affecting how hot it gets.  

    I am pretty sure it will cut back when it gets too hot.

    Often the maximum battery charging current is stated at 48.0v or lower battery voltage and as battery voltage rises its maximum charge current is less.
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  • MichaelK
    MichaelK Registered Users Posts: 234 ✭✭✭
    #3
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    It really doesn't say anything about state of charge, or overheating?  Here are the tables....

    from my manual

    from the DIY manual

    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,442 admin
    #4
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    Manuals are not always in sync with the hardware/software...

    I believe that the Midnite (and many other higher end brands) controllers have programmable max output current... If you can program to the higher value, it should be fine.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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