45 amp charge controller; need to add additional panels.

pyana1
pyana1 Solar Expert Posts: 39 ✭✭
in Solar Beginners Corner #1
my panels specs read :

Pmax: 252.23W
Voc: 37.87V
Isc: 8.57A
Vm: 31.14V
Im: 8.10A

I'm currently in Haiti with two (500 watts PV) and I would like to add two more identical panels... I have a Morningstar mppt 45 amp charge controller. by glance of the specs provided, can I add two more panels; totaling 1 kilowatt PV on my 45 amp controller.

or will one additional panel totaling 750 watts be ok

4 Trojans 450ah / 12 volt system
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Comments

  • scrubjaysnest
    scrubjaysnest Solar Expert Posts: 175 ✭✭✭
    #2
    If the 4 panels are wired in parallel then 4(panels) X (Isc)8.57 A = 34.28 A so that isn't a problem. Or should not be if there are no local codes against it.
    If the panels are wired series parallel then 2 panels in series Voc adds; so The new Voc is 75.74 volts at Isc of 8.57 A. Adding the second string in parallel gives a total Voc of 75.74volts and Isc of 17.15 A. Again not a problem if the CC can handle the voltage and I believe it can but not positive.

    Ok, just checked and the TS-mppt-45 is good for 150 volts
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #3
    pyana1 wrote: »
    my panels specs read :

    Pmax: 252.23W
    Voc: 37.87V
    Isc: 8.57A
    Vm: 31.14V
    Im: 8.10A

    I'm currently in Haiti with two (500 watts PV) and I would like to add two more identical panels... I have a Morningstar mppt 45 amp charge controller. by glance of the specs provided, can I add two more panels; totaling 1 kilowatt PV on my 45 amp controller.

    or will one additional panel totaling 750 watts be ok

    4 Trojans 450ah / 12 volt system

    Working backwards, with a charge controller that can handle 45 amps output, at 12 volt the charge controller can handle 12v x 45 amps = 540 watts, panels normally put out about 75% of their panel rating when hot, so to input 540watts you can effectively use about 750 watts of panels (750X.75= @560) so 1 additional panel should work fine. with 3 panel in parallel would not stress the charge controller as much a single string of 3 and would be the suggested use. If you went with 3 panels in parallel it will be suggested that you have a fuse or breaker for each panel.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • pyana1
    pyana1 Solar Expert Posts: 39 ✭✭
    #4
    By HIS grace, thank you guys 💪😎👊 .
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