Help interpreting manufacturers specs; Morningstar

outwestbound
outwestbound Registered Users Posts: 38 ✭✭
edited November 2018 in Off Grid Solar & Battery Systems #1
Hi. I got confused looking at an exhibit in the manual on page iii vs. other descriptions. Could someone please confirm what the maximum input open circuit voltage is for the Morningstar ProStar PS-15M when configured for a 12 volt system? Morningstar combines their descriptions of the 15M and 30M, 12V and 24V models in a way that I can't understand. My panel exceeds 30volts coming into the controller and the controller charges a 12 volt battery bank. 

Thanks. 
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #2
    Being a PWM controller you really need 12 volt panels. The controller has a maximum allowable voltage but when charging a 12 volt battery any voltage higher than about 18 volts will be wasted. You end up getting the current of your panel at the batteries voltage. Too many manual choices online to locate whatever pages you are talking about.
     It sounds like you have 60 cell panels, from the voltage mentioned. Your best bet would be to get an MPPT controller.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • outwestbound
    outwestbound Registered Users Posts: 38 ✭✭
    #3
    littleharbor2 said:
    Being a PWM controller you really need 12 volt panels. The controller has a maximum allowable voltage but when charging a 12 volt battery any voltage higher than about 18 volts will be wasted. You end up getting the current of your panel at the batteries voltage. Too many manual choices online to locate whatever pages you are talking about.
     It sounds like you have 60 cell panels, from the voltage mentioned. Your best bet would be to get an MPPT controller.
    Thanks and I agree with your comments. I've planned two systems in this small motorhome. Primary is a single LG 300 watt, 60 module panel going into a BlueSky 3000i MPPT for the reasons you described. I understand your comments. The secondary is a "suitcase" foldable 120 watt (3 x 40) array. For this foldable, I want an affordable PWM that will better suite this lower voltage panel, again, for the reasons you mention. BUT, if my primary 3000i controller goes down, I want to be able to install this PWM in the place of the dead 3000i. I will be overlanding in South America were having solar working is essential. 

    Hence, the question of voltage. I'll call Morningstar. Thanks 
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