tweaking charge controllers

baja1
baja1 Registered Users Posts: 13 ✭
in Solar Beginners Corner #1
I am so flippin lost.
having read suggestions for tweaking the mx60 to charge new trojan L16's I almost get it but I have 2 110watt panels that go to a sun saver mppt. this cc doesnt have the tuneability the mx60 does so if I have these two charge controllers stacked arent they both going to be doing something different at the same time?
this having different panels is a pain in the butt. I thought I had it figured out how to incorperate these two panels into the two strings of 75watt panels but coot set me straight(thank you sir). the idea being to simplify things with one controller.
so what are you supposed to do when paralleling two controllers?
thanks again guys!
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: tweaking charge controllers

    you were told by coot to go ahead and parallel the outputs of the 2 controllers to the battery. if one goes into say absorb before the other is out of bulk then you may need to bring the one that is better adjustable to the specs of the other one so they match. just how far off from each other are they that you don't think it'll work?

    btw, in the future do note that you don't need to start another thread that is covering the same ground as that other thread is. i don't feel like combining it with the other one at this point, but if it irks any of the other mods, be my guest.:roll:
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #3
    Re: tweaking charge controllers

    First, you don't worry about it. :D

    The Sunsaver is going to have "low" Voltage set points compared to what the MX60 can do. This is really okay, as it will mainly be contributing to the Bulk stage where Voltage is coming up from low and the Amperage flows freely.

    So the SS has an Absorb set point of 14.4 Volts. The Trojans want 14.8 for Absorb. Set the MX60 according to the Trojan recommendations and let it handle the last of the charging. During Absorb the Amps should drop off drastically, meaning you won't need full panel capacity. The 600 Watts on the MX60 should be plenty for Absorb on L16's. Once it drops back to Float the SS may contribute again as needed.

    That is if my recollection of two strings of four 75 Watt panels on the MX60 is right, and you only have one bank of L16's (320 or 390 Amp hours). Even so, 600 Watts of panel ought to run 52 Amps @ 14.8 Volts - on two strings of 320's that's 8%. Add in the push from the 110's and it should still work.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
    Re: tweaking charge controllers

    the 70a mod for the mx is an option too.
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