I bought the exact same setup, falling for the seller's wattage statement. When I tested and notified the seller, they sent me a partial refund of 2/3s of the price.
I can't understand why there are only 34 likes, this was a great video, potentially saving anyone wasting their money. Ebay should be ashamed of themselves for deliberately scamming their customers.
You're right. That's never a 120w panel at that size. Probably about 20w max panel. It would need to be around 50cm x 50cm to have enough cells to get over 100W on those construction panels. For nearly every type of panel tbh, Size of panel is pretty much the best indicator you have, not their package rating. Chinese ebay sellers are known for misquoting panel ratings, but they will replace if you threaten bad reviews, but that is a hassle if they don't just say "keep it, we'll send a refund". They sometimes do that, as most of the time people won't complain.
The best way to measure is to use a variable load. I start increasing the load until I start seeing the voltage drop quickly. I know that is the threshold the best it can put out. That looks like a 15 watt panel.
Why would you multiply no load voltage by short curcuit amps ? It's completely pointless. When you short circuit this panel as you had during testing amps, I bet voltage dropped to something like 0.1V, since internal resistance of your multimeter and copper wires together is around 0.1 ohms. Just multiply length and width of solar panel in meters, then multiply by 100, and you will have rough idea how much power it can produce. I've got 45cm x 20cm solar panel, labelled as 50W, while in reality it max out on 12.5V x 0.5A while charging car battery, under full sun. That is about 6W of power. 0.45M x 0.2M x 100 gives me out 9W, but effective solar surface is smaller than whole frame + this is polycrystal panel, not molocrystal, which lowers efficiency. In short, if you need 100W panel, it needs surface of at last 1M x 1M. Thank you.
Yea, not finding the optimum power point for the panel, but open circuit voltage x short circuit current is not normally far off the rated wattage. Usually within 10%
@@DanSohan I don't understand how, and why these 2 values would have anything to do with actual power of the solar panel. I mean, in electronics you never test anything under no load, or a short circuit. These are two extremes that don't prove anything. I would say you need a set of different resistance loads and then you measure actual current and voltage on these loads. If I'm wrong in here I would appreciate correction.
10 watts, I would say. Also, those plastic things last about a year if you use them fairly frequently. Really skinny wires. For glass with decent wiring try HQST or something like them. Even used panels can be a good deal if you can get a 12 volt locally. Lots of higher volt around but you need a MPPT charge controller for those which has advantages, but it substantially more expensive.
@@TimeSurfer206 Good to know. I used pwm on my car batteries during covid and it helped those live longer, but now I also have plug in trickle/float charger (cheap from Amazon) and also refurbished a higher amp plug in charger. Anything you can do to keep lead acid charged up is good. MPPT is also superior to PWM If you are buying used panels with high volts that have been on someones roof. A MPPT charge controller will regulate the voltage down to 12 volts or 24 volts per settings as you need, while PWM can only use power from 12 volt panels to 12 volt batteries, (or I think 24 volt panels to 24 volt batteries as well) so that's a big boon even though MPPT controllers are considerably more expensive. There also may be some cheap fake labeled MPPT controllers around that are actually PWM, so beware of that.
@@OWK000 "Anything you can do to keep lead acid charged up is good." AB SO STINKING LUTELY, as one of my Drill Sergeants would say (but he didn't say, "Stinking")" Not Fully Charged is the biggest cause of death for Lead-Acid. Overcharging is the second. Which is actually why I'm glad to see BMS's in the new batteries.
You were lucky, I bought a '600 Watt' solar panel from E bay and it achieved about 6 Watts power in bright midday summer sun. Got my money back and the company didn't want the unit returned. They are complete junk.
One look at it and I knew it wasn't so, Joe. "Size doesn't matter," and other lies the wife told me... 100 Watts should be about 42 X 21 Inches, AKA 1062 x 530 mm. For us Yanks, about half a bathtub long and almost as wide. I think I was through, like, 3 pages of WalMart listings before I found a "100 Watt panel" that was the right size. So, fine. I'll go to Hobo Freight.
I’m afraid your measurements are wrong. You can’t multiply open circuit voltage with short circuit current to get a meaningful result. Whilst I agree that the 150W rating is highly suspect, to find peak power you need to load the panel with a suitable resistance to bring the voltage down to the peak power voltage (maybe 12v?) and then simultaneously measure the current and multiply the two. A solar panel’s output power drops rapidly as it becomes over loaded!
Thats not how you calc the peak power. You took I and U at different points, shorted and no load. Besides that - I have the same panel, they sell them as 20 or 30W, They arent even 10. In full summer-sun when charging a battery they make 6W.
They aren't lying though, you'll get a total of 150 watts (more or less) in a whole normal sunny day with that panel. Still a misleading advertisement.
Tht solar charge controller only cost Usd4 and is the worst solar charger I ever used. I got 2 pcs of tht rubbish. It only last me for 3 weeks and most of the control buttons are faulty. China seller are the most scam seller in the world when it comes to online purchase.
Because it is fraudulent misrepresentation on the part of the seller when they advertise a solar panel which is, at best, 1/10th the output advertised. Pretty simple really.
@@markwelsh9068 That is very true but Capitalism is all about lying as much as you can get away with. The buyer knows he is getting ripped off all the time so he accepts that and incorporates it into his purchase. And so Capitalism marches on to even bigger lies.
I bought the exact same setup, falling for the seller's wattage statement. When I tested and notified the seller, they sent me a partial refund of 2/3s of the price.
I can't understand why there are only 34 likes, this was a great video, potentially saving anyone wasting their money. Ebay should be ashamed of themselves for deliberately scamming their customers.
Could be that people realize that a panel that size wouldn't normally generate 150w.
You're right. That's never a 120w panel at that size. Probably about 20w max panel. It would need to be around 50cm x 50cm to have enough cells to get over 100W on those construction panels. For nearly every type of panel tbh, Size of panel is pretty much the best indicator you have, not their package rating. Chinese ebay sellers are known for misquoting panel ratings, but they will replace if you threaten bad reviews, but that is a hassle if they don't just say "keep it, we'll send a refund". They sometimes do that, as most of the time people won't complain.
That's true . Also persons need to research before buying . Cheap prices can be to good to be true 👍
Maybe the seller was confused with a decimal point misplacement?
The best way to measure is to use a variable load. I start increasing the load until I start seeing the voltage drop quickly. I know that is the threshold the best it can put out. That looks like a 15 watt panel.
What, What, What, What, What, What, What, What, What, What.
Yeah only ten what's 😂
The same panel some sites selling as 1000 watt :)
Maybe they removed the decimal? 120w vs 12.0w thats pretty slick tbh. Not cool. Appreciate the info.
If they could make 150W panels that small for that cheap I wouldn't need batteries.
You should have known for the price. Never mind this is how ebay is.
Why would you multiply no load voltage by short curcuit amps ? It's completely pointless. When you short circuit this panel as you had during testing amps, I bet voltage dropped to something like 0.1V, since internal resistance of your multimeter and copper wires together is around 0.1 ohms.
Just multiply length and width of solar panel in meters, then multiply by 100, and you will have rough idea how much power it can produce.
I've got 45cm x 20cm solar panel, labelled as 50W, while in reality it max out on 12.5V x 0.5A while charging car battery, under full sun. That is about 6W of power.
0.45M x 0.2M x 100 gives me out 9W, but effective solar surface is smaller than whole frame + this is polycrystal panel, not molocrystal, which lowers efficiency.
In short, if you need 100W panel, it needs surface of at last 1M x 1M. Thank you.
Yea, not finding the optimum power point for the panel, but open circuit voltage x short circuit current is not normally far off the rated wattage. Usually within 10%
@@DanSohan I don't understand how, and why these 2 values would have anything to do with actual power of the solar panel.
I mean, in electronics you never test anything under no load, or a short circuit. These are two extremes that don't prove anything.
I would say you need a set of different resistance loads and then you measure actual current and voltage on these loads.
If I'm wrong in here I would appreciate correction.
10 watts, I would say. Also, those plastic things last about a year if you use them fairly frequently. Really skinny wires. For glass with decent wiring try HQST or something like them. Even used panels can be a good deal if you can get a 12 volt locally. Lots of higher volt around but you need a MPPT charge controller for those which has advantages, but it substantially more expensive.
But still absolutely worth the price.
I'm an Electrician. PWM will just kill your batteries slowly.
@@TimeSurfer206 Good to know. I used pwm on my car batteries during covid and it helped those live longer, but now I also have plug in trickle/float charger (cheap from Amazon) and also refurbished a higher amp plug in charger. Anything you can do to keep lead acid charged up is good.
MPPT is also superior to PWM If you are buying used panels with high volts that have been on someones roof. A MPPT charge controller will regulate the voltage down to 12 volts or 24 volts per settings as you need, while PWM can only use power from 12 volt panels to 12 volt batteries, (or I think 24 volt panels to 24 volt batteries as well) so that's a big boon even though MPPT controllers are considerably more expensive. There also may be some cheap fake labeled MPPT controllers around that are actually PWM, so beware of that.
@@OWK000 "Anything you can do to keep lead acid charged up is good."
AB SO STINKING LUTELY, as one of my Drill Sergeants would say (but he didn't say, "Stinking")"
Not Fully Charged is the biggest cause of death for Lead-Acid.
Overcharging is the second. Which is actually why I'm glad to see BMS's in the new batteries.
Strange, the thing works really well at 10W. Why say it is 150W? Maybe some problems with translation.
I think the eBay calculator is a faulty multiplication of every Amp and Watt, batteries, solar, amplifiers, you name it
You were lucky, I bought a '600 Watt' solar panel from E bay and it achieved about 6 Watts power in bright midday summer sun. Got my money back and the company didn't want the unit returned. They are complete junk.
One look at it and I knew it wasn't so, Joe.
"Size doesn't matter," and other lies the wife told me...
100 Watts should be about 42 X 21 Inches, AKA 1062 x 530 mm. For us Yanks, about half a bathtub long and almost as wide.
I think I was through, like, 3 pages of WalMart listings before I found a "100 Watt panel" that was the right size.
So, fine. I'll go to Hobo Freight.
He must mean 150W as in 150mm wide. God damn scammers
Seriously and how can they do such a cheating on a day light, every day of the year, totally Solar!
I’m afraid your measurements are wrong. You can’t multiply open circuit voltage with short circuit current to get a meaningful result. Whilst I agree that the 150W rating is highly suspect, to find peak power you need to load the panel with a suitable resistance to bring the voltage down to the peak power voltage (maybe 12v?) and then simultaneously measure the current and multiply the two. A solar panel’s output power drops rapidly as it becomes over loaded!
Thats not how you calc the peak power. You took I and U at different points, shorted and no load. Besides that - I have the same panel, they sell them as 20 or 30W, They arent even 10. In full summer-sun when charging a battery they make 6W.
Can confirm all you said.
They aren't lying though, you'll get a total of 150 watts (more or less) in a whole normal sunny day with that panel. Still a misleading advertisement.
Tht solar charge controller only cost Usd4 and is the worst solar charger I ever used.
I got 2 pcs of tht rubbish.
It only last me for 3 weeks and most of the control buttons are faulty.
China seller are the most scam seller in the world when it comes to online purchase.
Das Panel reicht max für 20 Watt , mehr nicht .
I was cheated also
🛌🛌🛌🛌🛌🐌🐌🌇🌇🌇 0:45
Why put Fake on your title if it works pefectly? Why do that?
Because it is fraudulent misrepresentation on the part of the seller when they advertise a solar panel which is, at best, 1/10th the output advertised. Pretty simple really.
@@markwelsh9068 That is very true but Capitalism is all about lying as much as you can get away with. The buyer knows he is getting ripped off all the time so he accepts that and incorporates it into his purchase. And so Capitalism marches on to even bigger lies.