diy solar

diy solar

Panels which seem a bit too inexpensive..

bluegoatwoods

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near the Great Lakes
Considering portable solar panels, my rough estimate has been about $100 for a 100 Watt panel. But I'm looking at some panel kits on Amazon at the moment and the price per Watt seems awfully low.

I would link to an example right here and now. But I'm unsure of forum rules on such stuff. I'm looking for that section in the forum as we speak. But I haven't found it yet. But maybe a description can get us where we need to be.

One vendor has several options at good looking prices. I think the brand name is LOPMQRV. An example of their options: A 3200 W kit with four 800 W monocrystaline flexible panels and two 40 A controllers. PWM, likely, though I haven't found confirmation yet. Panels are about 27 x 40 inches each.

I've been looking at it and calculating for days now. And if I understand correctly, then if I had these four panels deployed facing a good, strong sun then I might expect to draw (3200 W divided by 12 V) 267 Amps while that sun is shining on them? Or 67 A per panel. That seems huge! It also seems like it would be overpowering those controllers. So that's got me a bit suspicious.

Would I really be harvesting 3.2 Kilowatt/hours for every hour in that sun? If I had four hours of good sunlight, would I actually harvest 12.8 kw/hr in that four hours?

I guess those controllers will gobble up some of that power. But that's a detail. I ideal efficiency circumstances, are my calculations above realistic or have I overlooked something important?

The price on this particular kit is about $480. It just seems to be a good deal lower than I'd expect for that much power generation.
 
800 W monocrystaline flexible panel - Panels are about 27 x 40 inches each
If you look out your window you should still see the pigs flying by delivering those panels.
With claims like that I would also expect the controllers to be actual bricks

Some of the biggest scams often involve portable panels

As far as Amazon/product links - they're fine as long as they are not affiliate/partner profit making
 
An 800W panel would be huge. Far from portable, more like the size of a sheet of plywood.
Maybe read through those panel specs carefully one more time.
I wonder if he means 800 W total, so 200 W per panel

Edit. Nvm, I see now it’s 3200 W total.
 
Considering portable solar panels, my rough estimate has been about $100 for a 100 Watt panel. But I'm looking at some panel kits on Amazon at the moment and the price per Watt seems awfully low.

I would link to an example right here and now. But I'm unsure of forum rules on such stuff. I'm looking for that section in the forum as we speak. But I haven't found it yet. But maybe a description can get us where we need to be.

One vendor has several options at good looking prices. I think the brand name is LOPMQRV. An example of their options: A 3200 W kit with four 800 W monocrystaline flexible panels and two 40 A controllers. PWM, likely, though I haven't found confirmation yet. Panels are about 27 x 40 inches each.

I've been looking at it and calculating for days now. And if I understand correctly, then if I had these four panels deployed facing a good, strong sun then I might expect to draw (3200 W divided by 12 V) 267 Amps while that sun is shining on them? Or 67 A per panel. That seems huge! It also seems like it would be overpowering those controllers. So that's got me a bit suspicious.

Would I really be harvesting 3.2 Kilowatt/hours for every hour in that sun? If I had four hours of good sunlight, would I actually harvest 12.8 kw/hr in that four hours?

I guess those controllers will gobble up some of that power. But that's a detail. I ideal efficiency circumstances, are my calculations above realistic or have I overlooked something important?

The price on this particular kit is about $480. It just seems to be a good deal lower than I'd expect for that much power generation.
Likely they are using kWh for an 8 hour day and listing it as rated output…
Hat size panel can’t produce over 100W…
 
One vendor has several options at good looking prices. I think the brand name is LOPMQRV. An example of their options: A 3200 W kit with four 800 W monocrystaline flexible panels and two 40 A controllers. PWM, likely, though I haven't found confirmation yet. Panels are about 27 x 40 inches each.
Those are a scam. They were selling them under a different name a while back and I took a chance because I knew they were fake and had the cash to find out just how bad they were. Turns out they were just shy of 75w each in the STC test bed. I got a full refund but yeah, it's a scam.
 
Yup! The verdict is clear. I had a feeling that it was too good to be true. Those panels are only about the size of many 100 Watt panels, if nothing else.

I'll purchase something. But when I do it'll be something with more normal rated performance/price ranges.

Thanks.
 
For some reason flexible panels attract all the scammers.

Good way to sort out most obvious scams is to look at power output per area: anything abobe 200W per square meter is highly suspicious. After you sort out all the biggest scams you are still left with panels that have very short lifetime.
 
For some reason flexible panels attract all the scammers.

Good way to sort out most obvious scams is to look at power output per area: anything abobe 200W per square meter is highly suspicious. After you sort out all the biggest scams you are still left with panels that have very short lifetime.
Perhaps the way to deal with that would be to look for a recognizable brand.........say "Renogy" for instance..........and then look for plenty of positive reviews. Even that might not weed out all of the substandard components. But I guess it's the strategy that I'll follow.
 
Since the main topic here is just about buttoned up and put to bed, lemme go off topic before we call it a day.

I really am a newbie. Would you double-check my reasoning and my math?

I'm picturing a 100 Watt panel in my mind right now. Conditions are perfect so it is generating 100 Watts as we speak. This means that in the course of the next hour it will have produced 100 Watt/hours of electricity. That's correct, isn't it?

In my neighborhood we are advised to count on 4 hours daily average of decent sun. So I might expect this panel to produce 400 Watt/hrs per day on average? So if I had three of them I could calculate that those ought to produce 1.2 kw/hrs per day?

Naturally we'll ignore rainy days and such. My guess is that that's accounted for in that "4 hour daily" average.

But am I counting up those Watt/hrs and kw/hrs correctly?
 
I'm picturing a 100 Watt panel in my mind right now. Conditions are perfect so it is generating 100 Watts as we speak. This means that in the course of the next hour it will have produced 100 Watt/hours of electricity. That's correct, isn't it?
For the sake of discussion, yes. If it was in a lab. Actuality probably less.

My house panels, 405 watts each are at 60% of rating. My Lion energy panels can deliver 108 watts per 100 watts of panel rating in ideal conditions, so it overproduces. Overproducing panels are extremely rare. Panels not producing to their sticker rating becaus eof weather conditions is very common.
In my neighborhood we are advised to count on 4 hours daily average of decent sun. So I might expect this panel to produce 400 Watt/hrs per day on average? So if I had three of them I could calculate that those ought to produce 1.2 kw/hrs per day?
Use a solar calculator like in my signature block and find out for sure.
But am I counting up those Watt/hrs and kw/hrs correctly?
You're on the right track, just use a solar calculator like in my signature block or PV watts.
 
This means that in the course of the next hour it will have produced 100 Watt/hours of electricity. That's correct, isn't it?
No. It will have produced 100W for 1 hour, which would be 100 Wh (Watt*hours) of energy.
produce 400 Watt/hrs
400 Wh
So if I had three of them I could calculate that those ought to produce 1.2 kw/hrs per day?
1.2 kWh per day

Common unit error that happens all the time on this site, unfortunately. Power (usually measured in W or kW) is already a 'rate'. Energy (which is what batteries store) is power multiplied by the time over which that power is used or produced, so: Power*time = Energy. So Y Watts * Z hours = Y*Z Wh.
 
No. It will have produced 100W for 1 hour, which would be 100 Wh (Watt*hours) of energy.

400 Wh

1.2 kWh per day

Common unit error that happens all the time on this site, unfortunately. Power (usually measured in W or kW) is already a 'rate'. Energy (which is what batteries store) is power multiplied by the time over which that power is used or produced, so: Power*time = Energy. So Y Watts * Z hours = Y*Z Wh.
I think we said the same thing. Though I didn't know the proper abbreviation for 'kilowatt hour'. But I will keep "kWh" in mind.
 
The panel area is 1080Sqin… that’s .697 m2 so, they are advertising a panel that outputs 20% more than the sun sends to earth…
1000W/m2…
And the highest efficiency panel can only reach 50ish% of solar max… and NASA doesn’t even use those…
I smell a rat…!
 
I think we said the same thing. Though I didn't know the proper abbreviation for 'kilowatt hour'. But I will keep "kWh" in mind.
I think you're right that we're at least intending to say the same thing. It's the difference between Watts divided by hours (W/h) and Watts multiplied by hours (Wh). It seems like you're clear on what to do (multiply), just less clear on what the unit is supposed to look like written down. That fact that you multiplied already puts you ahead of many who get units confused on this forum.

As a sidebar, I think it has to do with fact that in normal non-technical life we very commonly see speed units in the form of mi/h or km/h (distance divided by time), but almost never see a combined unit that is one unit multiplied by another, so something like Wh or VA isn't as easily understood to be shorthand for W*h or V*A.
 
All the panels in my systems were about $20/200w 2nd hand

Good way to sort out most obvious scams is to look at power output per area: anything abobe 200W per square meter is highly suspicious.

I live by the 200w/m2 rule. It seems to work, you get what you pay for really when buying online, a 380w panel priced at $130, may only output 130w in the real world. For the price and the true output, it's probably fair.
 
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That is a great price! Wow...

When grid tie solar first emerged in Australia, many households got 1.5kw systems to get onboard. As time went on households would upgrade to 6.6kw systems making the 1.5kw kits redundant and sold off cheaply (or thrown away). My mppts are about 25% overpanelled, so inefficiencies of old panels aren't really an issue.
 
............... It's the difference between Watts divided by hours (W/h) and Watts multiplied by hours (Wh). ......................
Lemme see here.............If I try to see when dividing is appropriate and when multiplying is appropriate, I guess I'd start by imagining an appliance which consumes....let's say......10 Watts of power. If it were to run for one hour, then I would say that it used 10 W * 1 hour = 10 Watt hours of electricity. If it ran for 2 hours, then I would say that it used 10 W * 2 hours = 20 Watt hours of electricity. Is that correct? And is the proper abbreviation 20 Wh?

Looking at it from the other end......If I knew that an appliance had consumed 20 Wh of electricity and I also knew that it was rated at 10 W, then I could calculate that this appliance had run for 20 Wh/10 W = 2 hours.

And if I keep going down this road, I'll only confuse myself. At first, anyway.

Plus.....you've already been helpful by simply planting this question in my mind. There's no need for me to impose on your time and effort with further explanations. (Though if you see some awful error above which simply can not be allowed to stand, then I'd appreciate a 'heads up'.)

I'll simply keep in mind that I'd better nail down these abbreviations. I'll try to learn it by reading these threads. And I'll start by keeping in mind that a 'forward slash' definitely implies division.

Thanks and I'll see you around!
 
Lemme see here.............If I try to see when dividing is appropriate and when multiplying is appropriate, I guess I'd start by imagining an appliance which consumes....let's say......10 Watts of power. If it were to run for one hour, then I would say that it used 10 W * 1 hour = 10 Watt hours of electricity. If it ran for 2 hours, then I would say that it used 10 W * 2 hours = 20 Watt hours of electricity. Is that correct? And is the proper abbreviation 20 Wh?

Looking at it from the other end......If I knew that an appliance had consumed 20 Wh of electricity and I also knew that it was rated at 10 W, then I could calculate that this appliance had run for 20 Wh/10 W = 2 hours.

And if I keep going down this road, I'll only confuse myself. At first, anyway.

Plus.....you've already been helpful by simply planting this question in my mind. There's no need for me to impose on your time and effort with further explanations. (Though if you see some awful error above which simply can not be allowed to stand, then I'd appreciate a 'heads up'.)

I'll simply keep in mind that I'd better nail down these abbreviations. I'll try to learn it by reading these threads. And I'll start by keeping in mind that a 'forward slash' definitely implies division.

Thanks and I'll see you around!
Sounds like you’ve got it figured out!
 
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