Solar blanket performance
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ultrakiev
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The cells you are covering becomes resistors, drastically reducing output, normal for this type of panels. Hard to tell exact percentage depends on how panels wired internally ( series /parralel) on your particular panel. If you want something more efficient in a shadow you should get different chemistry panels like CIGS they don't reduce output as bad
as silicon panels.
as silicon panels.
Most panels have bypass diodes to mitigate shading penalties.
When you shade a cell, it's output current reduces. It doesn't really become a resistor as that implies you can force current through it by applying a higher voltage - you can't. It's more like an open circuit. Components in the same series circuit must experience the same current flow, so that cell becomes the roadblock for the rest of the cells in the string.
Panel manufacturers place bypass diodes at certain locations in the panel to allow series cells influenced by a shaded element to be bypassed. This allows the cells to continue to push the higher current, but they lose out on the total # of cells, so they push a lower voltage. Power is current * volts. Cut out half the volts, you cut out half the power.
Your average fixed panels tend to have the bypass diodes arranged such that the panel is divided into thirds. Shade most or all of a single cell in any third, and you take out the whole third. It appears your panel's diodes are arranged such that the diodes bypass 1/2 the panel.
When you shade a cell, it's output current reduces. It doesn't really become a resistor as that implies you can force current through it by applying a higher voltage - you can't. It's more like an open circuit. Components in the same series circuit must experience the same current flow, so that cell becomes the roadblock for the rest of the cells in the string.
Panel manufacturers place bypass diodes at certain locations in the panel to allow series cells influenced by a shaded element to be bypassed. This allows the cells to continue to push the higher current, but they lose out on the total # of cells, so they push a lower voltage. Power is current * volts. Cut out half the volts, you cut out half the power.
Your average fixed panels tend to have the bypass diodes arranged such that the panel is divided into thirds. Shade most or all of a single cell in any third, and you take out the whole third. It appears your panel's diodes are arranged such that the diodes bypass 1/2 the panel.
What's the specs on that blanket?
Price?
thanks
How come they aren't called solar sheets?
it is a 350W solar blanket for $260, but I don't think it comes nowhere near its spec'd wattage. I tried using a mppt and the regulator it provides, it delivers no more than 8.5 A on a clear day with good sun, I can't see how it can ever deliver anywhere near 350W. It is going back to the seller, I am afraid.What's the specs on that blanket?
Price?
thanks
How come they aren't called solar sheets?
Length and width of the portions holding the cells?
Are you absolutely certain that you're using a genuine MPPT SCC? Lots of fakes on the market, and that tiny thing sitting on top of your battery does NOT look like a legit MPPT.
Are you absolutely certain that you're using a genuine MPPT SCC? Lots of fakes on the market, and that tiny thing sitting on top of your battery does NOT look like a legit MPPT.
That is the pwm as supplied. I also used a Renogy mppt later, similar result.
MisterSandals
Participation Medalist
I would feel better owning a solar comforter. Bah dum bump.How come they aren't called solar sheets?
Length and width of the deployed panel? (just the part that has the cells)
How many Amps Renogy?
What is the sales link to your blanket?
Claimed Voc?
Vmp?
Imp?
Laying flat on the ground and not tilted correctly for your location and time of year will reduce your output.
Step 1:
diysolarforum.com
How to not get completely scammed when purchasing solar panels.
Too many times folks purchase panels from something like Wish or from anonymous on eBay, and they later realize they were sold LIES. Sanity check your purchase in the following two ways: Panel Length, L, in meters Panel Width, W, in meters. 1000W/m^2 * L * W * 0.2 = absolute maximum possible...
diysolarforum.com
By this calculation the total panel surface area is made up of 8 pieces of 32 cm x 32 cm tiles, so the max power output should be about 0.16 W, that does not make sense either. Sure it is delivering much much more than that. Something I miss in the formula ?
Claimed parameters are
Comments ?
Claimed parameters are
| Max Power: | 350W |
| Max Power Voltage: ( presumably VOC ) | 18.4V |
| Max Power Current: | 19.02A |
Comments ?
Terrapin
New Member
Shame it is nowhere near 19A. Tagging this to watch and see if you decide on a better mppt controller to try and get at least 15A.
I used a Renogy dcdc50 with mppt to test as well.
chrisski
Solar Boondocker
- Joined
- Aug 14, 2020
- Messages
- 5,309
I have similar results with shading ruining output.
For my 100 watt panels, I will test these in full sunshine by walking by them and have my shadow go onto the panel. I only shade these panels with my head, and out put will drop by 75%.
I don’t remember the exact output pwe square foot, but all solar panels should output the same wattage per square foot and if this calculation is off, I suspect a false advertisement. This has stopped me from buying some E-Bay panels. Those “blanket” panels are supposed to have even less output per square foot.
My Renogy Panels have come really close to rated amps at high noon angled towards the the sun. My Lion Energy Panels have slightly exceeded output. That is not a cloud in the sky sun.
For my 100 watt panels, I will test these in full sunshine by walking by them and have my shadow go onto the panel. I only shade these panels with my head, and out put will drop by 75%.
I don’t remember the exact output pwe square foot, but all solar panels should output the same wattage per square foot and if this calculation is off, I suspect a false advertisement. This has stopped me from buying some E-Bay panels. Those “blanket” panels are supposed to have even less output per square foot.
My Renogy Panels have come really close to rated amps at high noon angled towards the the sun. My Lion Energy Panels have slightly exceeded output. That is not a cloud in the sky sun.
Each of the 8 panels should be about 43 watts for 350 watts total.
32cm x 32cm is about 12.5" x 12.5"
Ok so how big is a real 50w panel or 100w panel compared to that?
Where did you buy the blanket from? Sales link?
chrisski
Solar Boondocker
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- Aug 14, 2020
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For a comparison, this is the unfolded dimension of the 100 watt panels I have that will slightly exceed the rated output maxing out at around 104 watts:
- Dimensions Unfolded – 26.5 x 40 x 1 inches
.32m * .32m * 8 = 0.8192m^2
0.8192 m^2 * 1000W/m^2 * 20% = 164W in perfect conditions.
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