Need the solar/power pros to weigh in

TantoTrailers

Well-known member
I’m out of daylight so I’m going to let it sit an hour and see where I am at according to the BMS. Right now with the fridge off it’s sitting at 100% and 12.98v.

9E1ADDD0-FEBB-4FC3-8F43-CD648161312C.png
 

luthj

Engineer In Residence
Its probably 98-99% or so. Remember a true 100% every few cycles is best to prevent sulfation. That's the absorb voltage until 1% of C.
 

TantoTrailers

Well-known member
Yes it definitely will get full charge frequently and after every use, including tonight. However, my trip to UT will be 9 nights without a plug so I need to make sure I can regain close to 100% using solar to compensate for the minimal use I tested with yesterday. My friend is bringing his generator just in case I need it but I really want to be self sufficient with what I have invested in thusfar, it will definitely be a true test...last long trip I had coolers, no fridge and a simple fuse panel.
 

dreadlocks

Well-known member
the low angle of the sun makes finding a shade free spot very difficult in the winter, then you subtract hours of actual sunlight and the poor angle on the panels and its a tough situation this time of year.

My portable solar was performing like a beast May-Aug, I had more energy than I knew what to do with.. but by late october it was getting really hard just to get non-diffuse lighting through the trees for more than an hour out in the field.

When the sun is high in the sky its easy to find a opening big enough to get sun on it all day, when its low in the sky you pretty much need to be far, far away from any trees to your south.. even an acre sized opening in canopy might not be enough depending on your latitude and the height of the trees.
 

TantoTrailers

Well-known member
In UT we will be out in the wide open with maybe a power pole for shade, not sure what to expect but I dont think shade will be an issue. The rack I made for my solar panels has legs that I can elevate them about 2’ on one end for better angle.
 

dreadlocks

Well-known member
Canyons and stuff arent much better, I was in Utah in october but I didnt spend much time out in the desert flats, when I did it was overcast all the time.. most was at altitude in the trees.. tho this time of year would be the time to be a desert rat, and would be really your best hope for decent solar right now..

Dont be afraid to hang em vertically if you need in the winter months, especially if snow is on the ground and you can catch reflections and wont have to clear anything off if it snows more.. there's solar calculator apps that will show you optimal positioning and angle you can put on your phone that can give you some good pointers.. anymore I just pull out my compass, find south and point it that way with some idea how the sun will track the sky based upon experience.
 
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TantoTrailers

Well-known member
I finally got to do some legitimate field testing in Utah. I ran my heater all night with the fridge in the galley and was able to recover every bit of power during a severely overcast and rainy day with just solar. Additionally I wanted to see if I could run all that + my snowboard boot dryers which are DC and draw 12-13w (also running all night) this consumed 23% of my battery after 10 hours. Last test was so try to regain it all with solar on another overcast drizzly day and it didnt miss a beat. An hour before sunset it was at 100% again.

Seems to me that my systems are all working properly! I will do some more testing in summer when temps are causing the fridge to run like mad.

Screenshot_20200123-073721.png

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Edit: I ran the panels in series the entire time and had them flat on my roof rack with no effort to angle them better.
 

shade

Well-known member
I finally got to do some legitimate field testing in Utah. I ran my heater all night with the fridge in the galley and was able to recover every bit of power during a severely overcast and rainy day with just solar. Additionally I wanted to see if I could run all that + my snowboard boot dryers which are DC and draw 12-13w (also running all night) this consumed 23% of my battery after 10 hours. Last test was so try to regain it all with solar on another overcast drizzly day and it didnt miss a beat. An hour before sunset it was at 100% again.

Seems to me that my systems are all working properly! I will do some more testing in summer when temps are causing the fridge to run like mad.

View attachment 563444

View attachment 563445

Edit: I ran the panels in series the entire time and had them flat on my roof rack with no effort to angle them better.
1579860442344.png
Mission Accomplished!
 

Chris-NC

New member
So much great and helpful information in this thread. I've been doing a lot of research on this topic lately as I'm putting together a solution for in my Jeep. This thread has probably answered 95% of my questions and concerns. Time to get to work now!
 

HongerVenture

Adventurer
Long time since I posted around here. This thread has taught me a lot as I prepare to put solar on my Troopy. Thanks for spending so much time documenting this! And spending the coin to learn so much. Really great thread.
 

67cj5

Man On a Mission
The Solar shop says they should be in series if sunlight is limited or if you have any shading on the panels, Which will give a higher voltage but the Amp output is the same as it would be for a single panel.

But in Parallel you get more Amps but the Voltage is lower and any shading can cause the voltage to drop below the desired amount,

It is confusing as to which way is better, They make a good argument for both setup's, In series' giving out 7 Ah from 4 X 150w panels is a good steady flow, But in parallel getting 28Ah from the same panels Sounds a lot better but the Voltage is lower on the input side of the MPPT Controller, I think in series should be called Winter setup and in Parallel should be called Summer setup, Or compromise by running the 4 panels in 2 banks of 2 so they are in series and parallel at the same time.

regardless of the above I am still not clear as to which is best
 

dwh

Tail-End Charlie
regardless of the above I am still not clear as to which is best
Voltage/amperage on the input side of MPPT is largely irrelevant - it's still gonna be the same amps at battery voltage on the output side either way.

The parallel vs. series question is about shading, which comes down to bypass diodes. I cover that in this thread...


 
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