Efficiency of my new Solar Panels?

[hickjo]

Hi all,
First trip away with new 120watt Kyocera panels through a PWM controller. Panels were reading consistent outputs between 90 and 105 watts through the readings on my Wattmeter. Is this an acceptable output range? I am happy for sure just wondering how this compares with others experiences! I was quite particular with the positioning of the panels and it was obviously spring sunshine here in Queensland.

[Peterr]

That's pretty good ..
Lots better than I expect to see from mine this weekend , given the weather forecast.. ....

[armbrup]

Its pretty good with a well setup panel with MPPT controller .

My cheapy set of 120watt panels puts out up to 7 amps at 14 volts which is about 100watts through an MPPT controller , 8 Gauge wiring and panels wired in series .

Regards Philip A

[robcaz]

Hard to say as the output of your panel will depend on how low your battery is ie if your battery is low the watts up with show more input from the panel than if the battery was near full.

[hickjo]

Hi,

Been a while since I originally posted but since then I have added another battery bank to my setup but I am yet to add more panel wattage to my 120W (PWM) set up to keep up with demand.....although these panels still allow us to go away for around 10 days and feed my 100Ah (just lights and pumps etc.) and 150Ah (just fridge) set up but be pretty skinny on available power by the end of the trip.
I am looking at another set of around 160-180 but I am wondering about current output of panels?? It would seem logical to go for big 200W panels which are pretty cheap but a lot of their rated current output is only marginally (2-3 amps) more than my current set up and this is much the same for 160-180W set ups. I understand that in a nut shell a good MPPT will lower the maximum voltage therefore increasing current output (Pmax/Vmp=Imp), hopefully I am grasping these concepts!

So I guess the best way forward is this...look for any size panel that puts out around 11-13 amps and then attach a kick ass quality MPPT controller to squeeze every bit of current out of what ever panel I choose.....thoughts?

[robcaz]

Ideally your battery should be fully recharged via the solar panels by early afternoon, so depending on your power useage you may need more solar to achieve this. By using Richard's Solar Spreadsheet you are able to customise a 12volt system to suit your own needs http://www.campertrailers.org/solar_spreadsheet.htm

An MPPT regulator gives the best possible output from a solar panel at any given point in time depending on the batteries state of charge. The max output from the panel is not needed to charge the battery, so by reducing the voltage, the MTTP regulator can increase the amps, especially so first thing in the morning or late afternoon, outside the peak solar sun hours. Peak solar sun hours is the number of hours when solar irradiance averages 1000 watts per square meter. For example in Sydney around the September equinox when we get twelve hours day & twelve hours night, there is only 5.6 Peak Solar Sun Hours.

While MPPT solar regulator manufacturers claim an added increase of 30% over a PWM regulator, the MPPT inbuilt regulator of the Redarc BCDC1225 sure gives us an added advantage charging our batteries when camped http://www.campertrailers.org/bcdc1225_feedback.htm

Our two 120 amp hour Rita AGM deep cycle batteries with an average daily power consumption of around 30 amp hours give us around four days camping with no sun using the rule of thumb not to allow the deep cycle batteries to discharge below 50% capacity. We run the 40 litre Engel fridge as a fridge by crovacing our meat to reduce power consumption http://www.campertrailers.org/fridge_draw.htm