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Efficiency of flat fixed solar vs adjustable portable?

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#21 JaSAn

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Posted 20 January 2017 - 02:59 AM

. . .  When my camper target weight is 650 pounds adding a second solar panel, 25 pounds, and a second battery, 55 pounds or 80 pounds is huge! So can I make what I have more efficient? . . .

 

IMO if you are trying to minimize weight the lightest you can go is fixed flexible panels on the roof and LIFePO4 batteries.  You are trading weight for $$$.

 

One thing I haven't seen discussed is with flex panels used as portables: one must provide structure to hold them rigid as they are aimed at the sun. The structure can equal or exceed the weight of a second flex panel.

 

As to batteries I don't understand your issue.  The battery weight will be the same for fixed or portable panels.  Your batteries are sized to run your loads and your charging system is sized to refill the batteries every day.

 

jim


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#22 Vic Harder

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Posted 20 January 2017 - 03:02 AM

Wow, great thread.  Best thought so far is that  "a 100w portable/suitcase is able to recharge batteries equally as well as a 160w flat fixed panel...if you're moving the portable to track the sun all day".  

 

I have yet to try out my solar setup.... real soon though!  On a "rest day" in the forest I will likely be using my portables.  Most often not, as the truck/camper will be parked at a trail head.  Too tempting for folks if the portables are out and deployed, so the roof mount will have to do the trick.

 

BUT, given Boonie's weight goals, I think maybe making the roof mounts easily dis-mountable for portable deployment might be worth looking at.  And I would look at 2 100W flex panels.  My reading of the info out there is we need 2x the AH of the batteries to ensure good recharge levels.


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#23 Bill D

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Posted 20 January 2017 - 04:01 AM

My reading of the info out there is we need 2x the AH of the batteries to ensure good recharge levels.

 

That's a good rule of thumb that I never heard of.  Thanks for sharing that tidbit.


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#24 Squatch

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Posted 30 January 2017 - 12:55 AM

In my limited testing under bad cloudy conditions, mid winter. My 100w poly portable will "roughly" double the amperage going into the battery through my Trimetric. My roof panel is a 160w mono.

 

I can't wait for a day with some real sun to get a better handle on how much the portable adds.

 

One thing no one has brought up. WIND! My roof panel is solid as a rock as is the camper in a bad storm on the beach in NC.

 

It doesn't take much of a gust to put the portable as risk of falling "glass panels". I haven't fullly worked out my leg system yet. but to prevent being blown around in modest winds it would have to be staked or weighted.

006%20Small_zpsgi2hq5ek.jpg


Edited by Squatch, 30 January 2017 - 01:15 AM.

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#25 ntsqd

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Posted 30 January 2017 - 02:23 PM

Based on that RoT I'm going to need to quadruple+ our 100W solar wattage. Which is going to mean roof lifter thingies.....

 

Saw a simple trick at a flea market in Bullhead City, AZ couple months ago. One of the vendors used 4 of those collapsing 5 gal. water jugs as anchors for the E-Z-Up in their parking lot stall. Filled with water during the day, poured back into their RV's water tank when done. I'd guess one of these tied to the apex of the portable's 3 legs would do the trick.


Edited by ntsqd, 30 January 2017 - 02:23 PM.

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#26 JaSAn

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Posted 30 January 2017 - 04:45 PM

 My reading of the info out there is we need 2x the AH of the batteries to ensure good recharge levels.

 

That rule of thumb was developed for fixed locations that have neither real estate nor weight issues.  If you can fit it, it won't hurt (one can never have too much solar).  I used HandyBob's minimum rule of 1X battery AH.  I am seldom below 100% in the evening.

 

Your requirements are specific to the latitude you camp at, what time of year, the amount of cloud cover, and how many watts you use per day.  There are many calculators out there, although most are geared to tilted panels it will give a general idea of how much sun to expect.  I use this chart:

 

http://www.solardire...-sun-hours.html

 

jim


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#27 Happyjax

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Posted 30 January 2017 - 05:07 PM

In my limited testing under bad cloudy conditions, mid winter. My 100w poly portable will "roughly" double the amperage going into the battery through my Trimetric. My roof panel is a 160w mono.

 

I can't wait for a day with some real sun to get a better handle on how much the portable adds.

 

One thing no one has brought up. WIND! My roof panel is solid as a rock as is the camper in a bad storm on the beach in NC.

 

It doesn't take much of a gust to put the portable as risk of falling "glass panels". I haven't fullly worked out my leg system yet. but to prevent being blown around in modest winds it would have to be staked or weighted.

006%20Small_zpsgi2hq5ek.jpg

Squatch, when you figure out that leg system let me know. I haven't come up with one either :)


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#28 DavidGraves

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Posted 30 January 2017 - 05:40 PM

Howdy all

 

We all know about the aftermarket adjustable wind deflectors commonly seen on pickups towing 5th wheel campers.

 

The are lightweight aluminum, easily adjusted for angle and secured by suction cups and straps. 

 

I have one to use as a donor for the angle tilt portion to make an easily adjusted panel.....not sure yet about fixed on roof or temporary on truck hood etc.

 

On another consideration, my T100 windsheild lies at about 45 degrees.....suitable angle for the Northwest and BC...I might instead just bungy it there....we mostly boondock and can position truck anyway we want in most instances.

 

DavidGraves 


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#29 Vic Harder

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Posted 30 January 2017 - 07:23 PM

That rule of thumb was developed for fixed locations that have neither real estate nor weight issues.  If you can fit it, it won't hurt (one can never have too much solar).  I used HandyBob's minimum rule of 1X battery AH.  I am seldom below 100% in the evening.

 

Your requirements are specific to the latitude you camp at, what time of year, the amount of cloud cover, and how many watts you use per day.  There are many calculators out there, although most are geared to tilted panels it will give a general idea of how much sun to expect.  I use this chart:

 

http://www.solardire...-sun-hours.html

 

jim

 

I am looking forward to seeing how well all this stuff works.  soon now!


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#30 DavidGraves

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Posted 30 January 2017 - 07:35 PM

Hey Vic

 

When does the sun come out in Alberta ?  LOL

 

Actually we just had the first day of Spring on the north Oregon coast.....first day of Summer will be July 7th.

 

David Graves


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