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Solar charging in shade


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A couple newbie campers with portable solar panels were claiming they were still getting a good charge even though their panels were in the shade.  I hated to break it to them that no, that's not how it works.  The panels need to actually be in the sun to work.

They see a voltage reading on their controllers, and they interpret that to mean they're working.  Of course we old-timers know that leaves out half of the formula for solar charging.

So.. whenever anyone claims they still get a charge in shade, remind them that we also needs to see AMPS on the gauge!  

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Correct, ITS "CHARGING AMPS" FLOWING THROUGH THE BATTERIES    "we needs to see"  to insure charging and that takes X amount of energy and a source  X volts HIGHER then battery voltage to accomplish . Of course, you still harvest some solar energy even in shade and/or cloud cover, just not near as much as if in direct bright sunlight WELL DUH. 

When my last RV was parked under the pole barn roof I still pumped a few charging amps into my battery and their voltage rose. In fact, the very reason I just added a fourth solar panel on my RV roof just last week was because when parked in total shade canopy tree cover (Ocala Natl Forest) and it was rainy n cloudy all day I wasn't quite able to achieve 100% SOC by early to mid morning as I do otherwise  grrrrrrrrrrrrrrrrrr so I'm hoping yet one more 235 Watt 24 Volt Panel might enable me to achieve my charging goals, but even if not, it will be closer.

 YES you need to see AMPS,,,,,,,,,,NO solar panels do NOT need to be in direct sunlight to harvest energy,,,,,,,,,,,,,,.BUT as we all know it sure helps lol

Nice chatting with you

John T           Live from Escapees 58th Escapade in Sedalia Missouri...........Solar and WiFi and Technology Seminars all week yayyyyyyyyy

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So how much of the charging capacity is someone likely to see in the shade?  10% of capacity?

I'm curious because I have the truck sitting under a carport of sorts at the moment.  I always keep a small solar panel on the dash to keep the battery from going low.  It works great when in open sun but not sure about the shade.  Not much power required to just keep the battery topped off, though.

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1 hour ago, oldbutspry said:

So how much of the charging capacity is someone likely to see in the shade?  10% of capacity?

 I don't have any hardcore precise or scientific measurements to answer that, solar energy harvest still depends on if the sun is direct overhead to the panels or at an angle and how bright it is. My best guess from experience is I got MORE then 10% in shade versus what it would be if I pulled the RV out into direct sunlight. Solar harvest is still greatly reduced in shade but I'm getting to the point I can still achieve nearly 100% SOC even if in shade and that was my goal so I'm not all that concerned as I'm about out of roof space anyway lol. 

Nice chat, thanks

I will be at an Escapade Solar Seminar in the next day or so, that's a good question for an "expert"

John T

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Agree... there is some charging in the shade.  I recall staying in Glacier NP at Apgar campground on cold, rainy days and even parked under trees for 4 days.  We conserved... a LOT... but still were good.

Full-timed for 16 Years
Traveled 8 yr in a 2004 Newmar Dutch Star 40' Motorhome
and 8 yr in a 33' Travel Supreme 5th Wheel

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In my conversion van I was parked overnight at Walmart. It was dark outside but I was directly under one of their parking lot lights. And getting a charge. I couldn't believe my amps were going UP at NIGHT! Those are some powerful lights!

Linda Sand

Blog: http://sandcastle.sandsys.org/

Former Rigs: Liesure Travel van, Winnebago View 24H, Winnebago Journey 34Y, Sportsmobile Sprinter conversion van

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6 hours ago, oldbutspry said:

So how much of the charging capacity is someone likely to see in the shade?  10% of capacity?

It's impossible to really put a number on it. Depends on the panels, region, depth/type of cloud cover, temps, topography, etc etc. but you'll still get a trickle... which can be enough to maintain storage levels, or more, if you have enough up top. For that matter, you can even pull a bit out of parking lot lights overnight. 😉

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2 hours ago, sandsys said:

...I was directly under one of their parking lot lights. And getting a charge.

Exactly.

Trivia: In the 1990's solar powered calculators made up more than 10% of the solar cell market... intended for indoor use.

My solar watches charger is a small l.e.d. array that fits neatly over the face. Solar devices and chargers are bound to expand as energy efficient devices become more prevalant, solar cell prices drop and efficiencies increase. The next iteration of solar cells just may be "solar recyclers" in your home used to reclaim energy used for indoor lighting. 😉

The morale? You can never have "too much" solar and sans direct sun can still produce "useable" amounts of juice.

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10 hours ago, Yarome said:

Exactly.

Trivia: In the 1990's solar powered calculators made up more than 10% of the solar cell market... intended for indoor use.

My solar watches charger is a small l.e.d. array that fits neatly over the face. Solar devices and chargers are bound to expand as energy efficient devices become more prevalant, solar cell prices drop and efficiencies increase. The next iteration of solar cells just may be "solar recyclers" in your home used to reclaim energy used for indoor lighting. 😉

The morale? You can never have "too much" solar and sans direct sun can still produce "useable" amounts of juice.

We have solar powered flashlights that sit on our windowsills just waiting for an emergency.

Linda

Blog: http://sandcastle.sandsys.org/

Former Rigs: Liesure Travel van, Winnebago View 24H, Winnebago Journey 34Y, Sportsmobile Sprinter conversion van

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12 hours ago, oldbutspry said:

Sounds like indirect light will be enough for my purpose. 

CONGRATULATIONS, having enough solar so you get by EVEN IN INDIRECT LIGHT is great, as said any solar is good solar and more solar (within reason and budget and practicality but still a free choice) is even better. If I always parked in the sun, never under trees, and it was never cloudy n rainy most of the day, I could get by with a lotttttttttt less lol.

 Happy Memorial Day, God Bless and thank all Veterans

John T Headed to Seminars, mostly Technology and Solar and WiFi and RV electrical at the Escapees 58th Escapade here in Sedalia Missouri

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