SunSaver SS-15MPPT with 200 watts of PV ?

easytim

Morningstar - SunSaver MPPT Charge Controller Model SS-15MPPT

The SunSaver MPPT charge controller is designed for 12V and 24V battery charging from PV modules with a maximum open circuit voltage of 75V. Use up to three 36-cell modules in series.

It can be used with 200 watts of PV when charging a 12-volt battery and up to 400 watts when charging a 24-volt battery.

I have a question,

I want to buy two 130 watt solar panels and use the SunSaver SS-15MPPT

My PV panels together produce 260 watts. will this work with the SS-15 MPPT?
It says it can be used with 200 watts, I'm not sure I understand what the 200 watts means.

Please give me a little help with this

mike95490

Re: SunSaver SS-15MPPT with 200 watts of PV ?

What is the Vmax power of the panels you are buying. If it's not more than 19V, the MPPT gains will be very small. The "magic" of MPPT happens with a high voltage array, being down converted to the battery voltage, allowing for smaller gauge array wires.

In your case, 260w of PV, *.8 (thermal de-rate) = 208W
So unless you have PERFECT tracking of the sun the entire day, your array will likely still be just under the 200W limit. Any brief peaks, the MPPT controller just throttles back to save itself, and then continues after it cools down. But you are at it's hairy edge.

BB.

Re: SunSaver SS-15MPPT with 200 watts of PV ?

I agree with Mike on the solar panel power output...

My GT system (warm side of the SF California Peninsula) typically runs about 2.5-2.7 kWatts maximum on 3.5 kWatts of roof top panels... Very rarely (a couple times a year for not very long) will I see near 3.0 kWatts:

2.7/3.5= 0.77
3.0/3.5= 0.86

260 Watts * 0.77 = 200.2 Watts
260 Watts * 0.86 = 223.6 Watts

If you are in a warmish area (60-90F) with roof mounted panels--you will probably be at or below the controller's limit 98+% of the time. And you will be controller limited by about 10% reduction in panel output.

If this is will be a very cool/cold/windy area with pole mounted array--you may wish to get a larger controller (the new TriStar, in another thread, is "due" in September--may be an interesting product to look at).

-Bill

Solar Guppy

Re: SunSaver SS-15MPPT with 200 watts of PV ?

Nothing "hairy" about it, The SunSaver can run 24/7 at 45C ambient at its rated current levels, its a 15 amp controller. If your charging at 14.4 , that 216 watts , or 432 watts for 28.8V, these are Bulk charging levels for typical battery's

For 260 watts of PV, you will probably never see any loss as you have to have the panels at 25C, 1000wmsq ( most locations are low 900s , this is the irradiance or strength of the sun ) and perfect angle to the Sun, none of which happen unless you on a high mountain, cold conditions and you have 2 axis tracking. Typical peak from those to panels will be just @ 200 watts.

You can run in series or parallel, at these power levels and typical temperatures it makes little difference to the mppt, you only need to be slightly above the charging voltage to have the Mppt 100% active. Even in my hot Florida climate, I am always above the bulk charging voltage with my panels typical about 65C on the roof. For an extreme location like the desert, then the two panels would be best in series.

easytim

Re: SunSaver SS-15MPPT with 200 watts of PV ?

Hey solar guppy,

So the SunSaver SS-15MPPT -15L will work well with two 130 watt panels in parallel then. Thats good news for me, I have ordered this combo. The hands on will help me understand its use better

Each solar panel is 12vdc @ 7 amps each

easytim

Re: SunSaver SS-15MPPT with 200 watts of PV ?

mike90045 wrote: »

What is the Vmax power of the panels you are buying. If it's not more than 19V, the MPPT gains will be very small. The "magic" of MPPT happens with a high voltage array, being down converted to the battery voltage, allowing for smaller gauge array wires.

In your case, 260w of PV, *.8 (thermal de-rate) = 208W
So unless you have PERFECT tracking of the sun the entire day, your array will likely still be just under the 200W limit. Any brief peaks, the MPPT controller just throttles back to save itself, and then continues after it cools down. But you are at it's hairy edge.

Thanks for the info - here is the panel I will be using
http://www.wildnaturesolutions.com/solarpanels.html

Vmax 19.8V
The 130 watt panel


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