450w fivestar solar panels

I fitted 13 x 450w fivestar solar panels facing north on a pitched roof. The very best they generate is a total of 2kw. Surely, even with some efficeincy loss, I should expect double that. I mean 450x13 is 5.6kw.

Did I waste my money? Fivestar themselves are not helpful at all.

There are other limits at play here as well that could influence this.
Your PV panels can only produce power if there is something that can use that power. Normally there will be 2 places that can use this power: 1) the inverter and 2) charging the batteries.

So to answer your question you need to look at what are the limits of those two pieces of your set up.
So what is the charge limits for your battery and also the charger? And what is your inverter size.
Then are these items looking to use all the power they can? Only at that time will you get the max out of your PV.

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It depends, maybe, maybe not.
I use 1 of these, certainly, before installation.
The last time my mate bought some “questionable” panels, he took his tester along and checked outputs as he bought his panels.
There aren’t surprises then.

Please supply more information. What inverter is used. How are the panels arranged (electrically - per MPPT, as well as physically - are they all facing the same direction, possible shadows etc.)

Also post the specs of the panels, as well as measured physical dimensions. Most fake panels can be detected by comparing their area with their output. If the efficiency calculation is more than ~22% at 1000W/m² then that’s a very strong indicator.

Thanks for the response so far.

The inverter is a fivestar and I have scrutinised just about every setting. Also changing some settings to see if i get better results. I have also had a second electrician around because the person who installed the system wont talk to me anymore.

All panels are facing same direction and in full sun.(no shade at all) believe me, I check that. They are also on a single string.

At this stage, its evident that fivestar under delivers on its specs. Even the inverter claims to be 8kva, yet it trips when I exceed 4.5kva. Another frustrating thing is that despite the solar, with loadshedding the inverter hasnt been able to keep the batteries fully charged. Even at night when almost no current is drawn, it trips.

Geyser is a heat pump with timer and only uses 600w, and pool pump 450w only runs in the day. The inverter will indicate the power I use and I am very disciplined on that.

I will do the comparison between two panels and let you know. Just need to get one off the roof and find another to compare with.

Dimensions are 988 x 1642


Hmmm, 39.59*9.6 = 380W, so at best those panels are 380W panels. They are also about 20% smaller than these 380W canadian solars:

So, my guess is that they are 310W panels at best. The rest I would happily ascribe to the inverter just not being good at MPPT.


Perhaps there’s another explanation (or additional): 13x40 = 520V, which is higher than the MPPT operating 120V - 450V (ignoring Voc). So I assume that all the panels are not arranged in a string, else the MPPT will pop sooner rather than later. But now you have 13 panels, in some configuration that involves parallelling them. So 6S + 7S = 6S + 6S and assuming the MPPT can only do ~10A (it says 100A on the spec, but I’m sure that is a typo), so really only have 6S. Then even if they are 450W panels, you will generate 2.7kW at most, allowing for inefficiencies (angle of sun this time is year is rough), you sit with 2kW.

Yes, I saw the odd number of panels and immediately thought about that, that is the reason I asked for the electrical configuration…

That said, there is no way those panels are close to 450W.

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The OP did say they are on a single string, but they could have been parallelled on the roof with a single string coming down to the breaker/fuse. Perhaps the OP can check the voltage across the breaker?

Those are similar specs to my older 330W string so I would guess that is what you have.
unfortunately I have seen Chinese marketing and they will slap any number on a lable to make you buy their item over the next one.

Thanks for the replies. I think my suspicions have basically been confirmed. I have been ripped off. No wonder the guy who supplied and installed has blocked me and wont answer my calls.

There is then little else that I can do but accept that I have bought 300w panels labelled as 450w panels.

The next step is either to replace the panels or add another string of panels that produce similar power.

If I were you I’d still check the voltage on the MPPT. You do not want your MPPT to pop and be out of pocket on the inverter also…

you have been mislead those are definitely not 450W

I have Canadian solar panels 445w and this is the dimensions

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Yes, either that, or one dud panel screwing up the whole string.

The spelling mistake on the back is not a good sign either. “Cryatalline Siticon Photoyot taic modutes”? Even in French that makes no sense.

Multiple strings? AS @_a_a_a said, odd number of panels (13) so either all in one string (which would way exceed what the inverter can handle), multiple MPPTs (I don’t think that inverter has more than one), or paralleled in some weird and wonderful way (13 is not only odd but also prime… there is no way to do it on a single MPPT other than one string, or 13 strings).

It is not unheard of for some “installers” to simply leave some panels unconnected. But even if they only connected 10 of the 13 (which would yield a safe voltage range for the MPPT), you should get over 3kW of PV.

It would also be interesting to see what voltage the panels actually run at. Measure with a multimeter, on the input of the MPPT, carefully as this is hundreds of volts. Or unplug the MC4 connectors and stick the multimeter probe down there. When there is no load on the inverter and the batteries are full, the panel voltage should rise to their open-circuit voltage, which means you can do a division sum to find out how long the string is.

Maybe they just made a 6+7 arrangement? Paralleled a string of 6 with another of 7? That would basically half the production, and can be “fixed” by removing one panel from the longer string.

But totally guessing here. If you don’t know what you’re doing, rather get an expert out there.


The spelling mistakes didnt go unnoticed.


The panel code suggests a JA Panel but the particular series of panels in the “72S30” range seem to start at 525W.

As @_a_a_a pointed out the panel specs suggest a 380W panel. You will find exactly one hit on google with those exact specs which is listed as a 380W panel (don’t bother to google, no need to send them traffic).

Other than the spelling issue the label looks misaligned, like it was cut with a fairly blunt cutting instrument and also stuck down with “pritt”. Will be interesting to know if the serial numbers at least vary…

Legitimate companies also make errors - legitimate or not (my money on not) they should have used a ruler when reading spec sheets to create a label (this table is from a JA Panel manual - compare numbers to Panel specs)

Maybe you are lucky to have panels in the 350W range since the bulk of information points to that is what was either produced or what it was made to look like.

If you measure your panels maybe you can find the closest match to get an idea of worst/best wattage to expect from the possible corresponding JA series.

Edit: did not notice the posted dimenions 988 x 1642 (my bad)

Edit2: based on the panel dimensions I think OP will be lucky to have panels in the 200W-300W range

Based on that list of JA panels, and assuming the measured size is a few mm off (it is not as if these things are 100% identical anyway, so I discovered over the years), then we’re looking at the 1650 x 991 panels, or maybe the 1657 x 996 modules. That means the panel might be only 330W or so. At best!

Edit: In short @Bugs, someone took you for a moerse ride.

Edit 2: I would also be willing to bet that not only are they smaller panels that were re-labelled, they are likely also not “grade A” solar cells. That’s another scam I’ve seen, taking grade B panels (which match the electric spec, but shows some flaws) and selling them at full price.

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Please if you are in Gauteng get one to me. I offer to test it…

There is so many panels being sold with fake labels…

We often warn people to stay away from these cheap chinese brands, but cant reach everybody.


maybe have a section for fake equipment on the forum and have the threads follow a standard template - at least in that way the search engines are likely to pick up on it which could help more people be educated what to look for.

Have the thread titles something like “Fake 450W panel labelled as fivestar” , then also include photos of panel, panel label, dimensions and ideally testing results. ?? This may unfortunately also help educate the scammers how to improve their fakes but hopefully save some people from getting conned.

If the installer / supplier “ghosts” the person then naming the party might also be considered appropriate ?? (obviously a can of worms that but the original poster should have invoices, screen caps of messages to back up their claims as they will still need to be able to defend against defamation claims).

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