Be cautious of panel claimed watt ratings from certain sellers.

[Mattb4]

I was looking at solar panel prices on Ebay and I happened to notice several new 200w Mono and even 300w panels for RV that seemed like a good buy with free shipping even. However when I looked for the size of the panels I noticed something wrong. Ones from a company named Tatooda (a few other no name) were the same size as 100 watt mono panels that I just recently bought. It is not possible to be double watts or triple watts in the same size. I also note that the voltage for the panels is similar voltage as my 100watt panels.

So before you buy panels do your research. My new 100w mono panels are about 20 X 40 inch in size (102cm by 51cm). In order to get 200w, based on math, you would need double the square inches or square cm.

Hate to see people buy and go to the effort to install such panels and find that they do not get the watts they expect.

 

[Lt.Dan]

39"x64" is very typical for 60 cell 250-300~ watt panels.

I have seen ads like you are talking about before. I even saw one for a 500w panel that was 12v output

 

[GregTR]

You can't save everyone.... There were literally thousands who bought solar installs from Pink Energy.

 

[Mattb4]

You can't save everyone.... There were literally thousands who bought solar installs from Pink Energy.

True enough but sometimes it does help a few to give them a heads up. It is easy to get carried away and not read the fine print or notice discrepancies. Especially so when you expect a bit of honesty. Imagine if every time you went to buy gas you could not trust the amount the pump displayed?

 

[Charleswgibbs]

It pays to check the math!

In another thread someone was interested in these panels:

https://www.amazon.com/dp/B0B8CHDDNY/?pldnSite=1

They are rated at 300w but seemed awfully small for 300w panels so I did some quick math.

From the other thread:

"We get about 1000w per square meter. According to their dimensions the panels are .64 square meters, which is 640w

They say the panels are 22% efficient
.22 x 640w =140w which is less than half of the 300w rating."

 

[GregTR]

It pays to check the math!

In another thread someone was interested in these panels:

https://www.amazon.com/dp/B0B8CHDDNY/?pldnSite=1

They are rated at 300w but seemed awfully small for 300w panels so I did some quick math.

From the other thread:

"We get about 1000w per square meter. According to their dimensions the panels are .64 square meters, which is 640w

They say the panels are 22% efficient
.22 x 640w =140w which is less than half of the 300w rating."

The specs are in the actual listing.


Vmmp = 18V
Immp = 5.55A

These are 100W (18x5.55=99W) panels, not 300. The 300W is total BS. But if you can't read the specs you probably won' t care if they're 300W or 100W panels as you have no idea what 300W vs. 100W really means either...

 

[Mattb4]

Boy that setup being sold through Amazon is really outlandish. $630 for 4 highly over rated panels, 2 garbage PWM SCC and for some odd reason 8 carabiners? What are the carabiners for?

 

[Charleswgibbs]

Didn't even notice the carabiners! ?

Maybe it's their idea of cable management

 

[Vigo]

No you drill holes through the solar panels and hang them from some eyelet hooks, those are included too right?

Sucks, but doesn't surprise me.. I once bought one of those 100a rated 12v pwm charge controllers for like 12$ because i kinda figured i was ok paying the $12 for the 10a controller it probably was. Got it, has 100a written on the label ON the unit (not just the box, or the listing), opened it up and it was identical to a different 10a one i had. Woulda definitely sucked if i had paid 100a controller worth of money for it!

 

[Lt.Dan]

No you drill holes through the solar panels and hang them from some eyelet hooks, those are included too right?

Sucks, but doesn't surprise me.. I once bought one of those 100a rated 12v pwm charge controllers for like 12$ because i kinda figured i was ok paying the $12 for the 10a controller it probably was. Got it, has 100a written on the label, opened it up and it was identical to a different 10a one i had. Woulda definitely sucked if i had paid 100a controller worth of money for it!

Would have really sucked to put 100a through it, and it caught on fire! Lol

 

[Vigo]

Yeah and realistically, i was 99% certain it was bullshit just based on the physical dimensions, same as the original topic here.. but that's the kind of context clues that people with no background knowledge are incapable of picking up on. So even though these shitty sellers are just humorous and old news to a lot of us, they ARE still creating victims and it's still good to have a thread like this sitting on the first page of the first section of a forum like this, so a truly new DIY'er is instilled with a sense of skepticism and caution! That's the best knowledge you can start off with!