On-Truck Solar Panel Charging Parked INSIDE the Garage?

[Dissent]

EDIT - This was a battery charging thread but is only a waste of time now. Don't read.

I have an onboard CTEK charger and an ARB 50 fridge plugged into a 120v surge suppressor which I plug into my garage outlet every night to keep the battery and fridge charged. During the day, the 100w Renogy solar panel keeps the battery charged with the fridge feeding from the truck battery.
As I plugged in last night, I checked my Victron solar charger and noticed the panels were receiving 6.5v with ambient daylight in the garage. I turned on the garage fluorescent lights and it went to 7.5v. It dawned on my that instead of plugging into the wall every night, why couldn't I just position a light above the solar panel and let it charge using the solar panel as I do during the day? Here's a pic of how the panel is oriented on the truck. The light in the pic is off on the aisle about 18" outside the edge of the panel.

Is anyone doing this and do you have advice about what kind and size of light would be needed if I positioned something about 1.5 feet above the panel?

 

[mct75]

I've looked into this, the light you would need would have to be insanely bright. Like, a 1000W spotlight to get 100W of solar power.

Something like an auto-eject shore power plug would be fun if you don't want to worry about dragging the cord away when you drive.

 

[BILT4ME]

The loss of efficiency between leaving the light on and plugging in the truck..........

 

[Dissent]

I've looked into this, the light you would need would have to be insanely bright. Like, a 1000W spotlight to get 100W of solar power.

Something like an auto-eject shore power plug would be fun if you don't want to worry about dragging the cord away when you drive.

I'm not worried about the plug, I'd just rather not deal with it. It's just one more thing to deal with.

I'm looking at LED or Fluorescent light sources. I have a crazy bright 4' LED bar in my shed that sips energy but I'm not sure what it's light output is. Before buying and experimenting with different solutions, I wanted to reach out to see if anyone else is doing this.

 

[Dissent]

The loss of efficiency between leaving the light on and plugging in the truck..........

I'm not looking to save money or the planet at this point. Just want to see if it's feasible. Light source would be LED or Fluorescent when I do get back to that part of it.

 

[mct75]

LED bar in my shed that sips energy

if the bar sips energy, you'll get maybe 10% of that energy into the panel, and less into the battery you are charging. A 100W light bar might get 5W into the battery all said and done.

 

[Dissent]

if the bar sips energy, you'll get maybe 10% of that energy into the panel, and less into the battery you are charging. A 100W light bar might get 5W into the battery all said and done.

I understand there are massive inefficiencies involved. I believe the solar panel itself is only about 15% efficient so if you had a 100w light, it would only receive say 15w but I'm not entirely sure if light wattage has a direct effect on photovoltaic absorption. During the night, the only real draw on the battery is the fridge. I don't need a full 5A fed into the battery as I would in direct sun in the Phoenix summer, I'd guess less than 1A is required to keep things happy given the amount I've seen the fridge cycle while in the garage at night.

I don't have any empirical numbers yet, I literally just came up with this last night. The wattage output of a light source may not be critical, but the wavelength and intensity of those waves might play a more critical role. Incandescent bulbs do affect solar panels but their wavelengths vary. I'm not sure about LEDs or Fluorescent wavelengths at all.

I've seen bright LED panels used in commercial lighting (5000 lumens @ 50W) but I'm not sure how a photovoltaic cell reacts to LED light. I obviously need to play with it but thought I'd reach out for first hand experiences first.

 

[mct75]

It's a neat idea, and will definitely work, but you're still looking at hundreds of watts of light (that needs to be focused all on the panel) for tens of watts of power into the system. And if your average power draw is only 1A, a deep cycle battery could provide that current for days without an issue.

Fun idea, just wildly impractical.

 

[SmokingRocks]

I run shire power in the garage because even with my LED garage lights on my 100w panel doesn’t produce a fraction of what the fridges are taking off the battery in an hour.

Shore power is easy and efficient, is the world really getting to the point where taking the 5 seconds to plug in shore power is just too much to fathom haha jeez

 

[Dissent]

It's a neat idea, and will definitely work, but you're still looking at hundreds of watts of light (that needs to be focused all on the panel) for tens of watts of power into the system. And if your average power draw is only 1A, a deep cycle battery could provide that current for days without an issue.

Fun idea, just wildly impractical.

Oh, I never claimed that this was going to be practical.

I already have an X2 Deep/Start battery. It will last 2-3 days sitting before it needs attention but I still want to satisfy my curiosity about this.

 

[Dissent]

I run shire power in the garage because even with my LED garage lights on my 100w panel doesn’t produce a fraction of what the fridges are taking off the battery in an hour.

Shore power is easy and efficient, is the world really getting to the point where taking the 5 seconds to plug in shore power is just too much to fathom haha jeez

That's the actual feedback I'm looking for.

For the record, I do have a NOCO shore power port that I will be mounting on my Prinsu roof rack but I haven't dealt with the 2nd roof penetration for it yet. Right now, I slide open the rear window, drag out the cord end and plug it into the dangling charge cord from the ceiling.

I'm not quite that delicate. It's not the 5 seconds, it's a lot of movements that requires both hands to be free and it's just a PITA when I have to carry a few things out of the car with me. Eventually I'll get the port installed but I need to get another Blue Sea deck penetration puck (I ran a 7x lead trailer wire through the other side for lights/solar connections). Why not in the bumper you ask? I will trip over it constantly. I have plenty of power in the ceiling and there's too much foot traffic around either end/side of the truck in the garage.

 

[BILT4ME]

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[Broski]

sorry for the hijack. But I'm just curious the ARB fridge is a heavy fridge I only put mine in if I'm going on a multi-day trail run. The rest of the time I just use a small Igloo cooler with blue ice in it for one-day runs. I know you're not living out of your rig or you wouldn't be parking it in your garage. That's a lot of fridge to put your daily lunch in. Ok hi jack over.

 

[Dissent]

sorry for the hijack. But I'm just curious the ARB fridge is a heavy fridge I only put mine in if I'm going on a multi-day trail run. The rest of the time I just use a small Igloo cooler with blue ice in it for one-day runs. I know you're not living out of your rig or you wouldn't be parking it in your garage. That's a lot of fridge to put your daily lunch in. Ok hi jack over.

It's always in there...and yes, it carries my lunch too. It's so much easier on the fridge to just keep it running and stocked (keeps the load down as the temp is much more consistent full of water and stuff). The fridge is mounted and wired and part of the truck now. No more coolers...ever...

 

[SmokingRocks]

It's always in there...and yes, it carries my lunch too. No more coolers...ever...

You aren't kidding that was the best money I've ever spent on mods (plus the solar panel). I loved my fridge so much I got it a friend....

 

[paulzak]

Not feasible. Grossly inefficient. Just plug the thing in.

 

[Dissent]

Not feasible. Grossly inefficient. Just plug the thing in.

LOL. I love the simple answers from those that aren't doing the work on a daily basis.

Anything is worth exploring, half my 'innoventions' are based on things I dreamt up. Most are successful.

 

[SmokingRocks]

If you cut a giant skylight in your garage it would probably work.

 

[jaymar]

Now maybe someone can tell me why I’m wrong about this, but it occurs to me that… Mirrors.

Update:

Mirror-boost for solar panels

 

[clx16]

So I tried to find a youtube video to describe the solar panel testing that is done at manufacturing places, but I could only find the individual cell "flash"testing. Essentially they do NOT take the panel out in the sun to test them they use LED matrix panels and test the output. one thing that keeps the light from escaping around the room is the light panels are right up against the panel. If you could focus the light from a few of the LED lights that you get from place like harbor freight (i have these and really like them) you might get what you want. I think you will want to get them very close to the panel.

Have you considered something else that is unconventional... inductive charging? If you can charge your toothbrush and cell phone through it, you could just scale up