You get what you pay for.......

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Kathy & Bill

Kathy & Bill

Well-known member
Joined
Oct 1, 2017
Posts
98
Well... as the saying goes.. "You get what you pay for".

I bought 4 - 200 watt flexible panels from China.  The wattage each put out are.. 70, 60, 48 and 46 watts, for a grand total of 224 watts when wired in series.  For a supposed 800 watt array in full sun and no shading, 224 watts is pathetic in my thinking.  Maybe I'm missing something but it seems pretty meager to me.

From panel array to controller the wire is #8 awg with 30 amp inline fuse and disconnect switch.  From controller to batteries the wire is #6 awg with 50 amp breaker inline.

Any thoughts.. if I got something wrong or just cheap A** panels?
 

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Looks pretty low to me and I don't see anything wrong with your setup..  Flexible panels aren't known for durability - they have just a spattering of active material on a flexible substrate instead of actual photovoltaic crystals.  How did you come up with the wattage produced by each panel?

The hot deal right now is in used crystalline panels.  A lot of panels that were installed on buildings to get the tax credits are now fully depreciated and being removed.  SanTan Solar in Gilbert, AZ and many other online dealers are selling used 250 watt rigid panels for $50 - $90 each.  These are nominally 24 volt panels and a parallel connected array will work well with your MPPT controller.
 
They probably wrote the ad so that they can say that it is a 200 watt panel,(panels).  The inference is 200 apiece.

One problem is that if you are mounting them on the roof where space is limited then you may eliminate the possibility of putting a serious amount of solar on the roof.

This was about 800 watts on my old Stacker trailer, 5 X 160 watts.

In about the same space as that 224 watt array you could almost put 3 of the 160 watt panels for 480 watts.
 

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Lou Schneider said:
Looks pretty low to me and I don't see anything wrong with your setup..  Flexible panels aren't known for durability - they have just a spattering of active material on a flexible substrate instead of actual photovoltaic crystals.  How did you come up with the wattage produced by each panel?
Click to expand...

I hooked them up individually to the controller and looked at their output through the Victron app.  I would have been happy with half the rated output, but a little over 25% of their supposed rating is not right.
 
HueyPilotVN said:
They probably wrote the ad so that they can say that it is a 200 watt panel,(panels).  The inference is 200 apiece.

One problem is that if you are mounting them on the roof where space is limited then you may eliminate the possibility of putting a serious amount of solar on the roof.

This was about 800 watts on my old Stacker trailer, 5 X 160 watts.

In about the same space as that 224 watt array you could almost put 3 of the 160 watt panels for 480 watts.
Click to expand...

Yes.. I have seen that deceptive tactic in adds.  The ones I bought were indeed advertised as 200 watts each.  I will contact the Ebay seller and see what he has to say.  I'm not holding my breath for a resolution for this.
 
Try running the four panels in parallel. See attached.
 

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FWIW Bill, I've spoken with thousands of people/customers over the past few years, and of those who had purchased the less expensive (i.e. cheap) Chinese flexible panels, literally none were happy with them. One guy told me his worked better as a doormat.

Those used panels Lou mentioned look like a darn good deal - if you've got room on the roof to mount them, or room to store them if you set them up outside.

Kev
 
I see lots of shading on those panels. Particularly the top half. Are you sure you had full direct sun?

Sun angle and even minor shading will kill your collection. Are you running an moppt controller?

Also flexible panels rarely give out full rating. HueyPilotVN has a setup that would be a lot more predictable/satisfactory.
 
I'm sorry you found out the hard way, a simple pm to me and I would have set you straight..
flexible panels are to be avoided at all costs.. great door mats useless as a panel.
you will have low output and a short life with these..
hopefully you did not pay more than 25 cents/watt..


 
Kathy & Bill said:
I hooked them up individually to the controller and looked at their output through the Victron app.  I would have been happy with half the rated output, but a little over 25% of their supposed rating is not right.
Click to expand...
What time of day did you take the readings?  Should be around noon sun time (no daylight savings time).

What part of the country were you in?  At the Mexican border or how far north. 

What was the condition of the sky?  Pollution and any haze reduces the output.

Does the Victron show you the voltage and current (and/or watts) at the input to the controller, or were you looking at the output of the controller? 

You have a MPPT controller which works best at higher voltage something like 35-50 volts.  You most likely only have 17-18 volts from individual panels (maybe a bit higher voltage since the panels are supposed to be 200 watts each).  Wiring in series will bring up your voltage to take advantage of the MPPT.
 
I'm curious what load you used to check the voltage and amperage for each PV. Did you compare the wattage of all four in series vs. individually / parallel? Before everyone tells me it doesn't matter I understand P=EI. Depending on the hardware used R may vary and if one PV opens in series your system won't charge. You're really better off going parallel from the PVs to the voltage regulator in my opinion.



 
AStraveler and Tom55555 both could be right...

If you have a 12V battery set up, 12V panels and ~400W with an MPPT controller, parallel wiring is usually the way to go.

If you have a 24V or 12V battery system, >12V panels, >400W with MPPT controller, series or series parallel is the way to go. you must make sure that the MPPT controller is rated for at least the total combined voltage of the array. You can't hook up 48V solar to a controller rated for 24 or 36V for example.
 
If you've got an MPPT controller and multiple 12 volt panels, or one or more residential panels, it's usually best to wire them in series. An MPPT controller can convert their combined voltages to amps, which can enable the system to start charging a little earlier in the day, and a little longer throughout the day. MPPT controllers convert the excess voltage of combined panels to amps, so the "extra" voltage isn't wasted. PWM controllers can't do that. The higher voltage also enables thinner gauge wire to be used.

The only real downside of wiring panels in series vs. parallel, is that if one panel gets shaded, it affects the other panels to. Newer panels aren't as affected by shading as older panels, but they're still affected.

Kev
 
That's why the 400w rule of thumb is suggested. One panel shaded cuts your output by a bunch and 4 X 100W panels will usually be mounted "near" each other. An 800w array is less likely to get severely cut back from one panel being shaded as the square area is a ton more. But you also need a serious controller and at that point you are starting to consider series parallel wiring at 48V.

Another option if one expects to get shaded is to separate the panels and do 24V series parallel in pairs.

Kevin Means said:
The only real downside of wiring panels in series vs. parallel, is that if one panel gets shaded, it affects the other panels to. Newer panels aren't as affected by shading as older panels, but they're still affected.

Kev
Click to expand...
 
Thank you all the replies, I'll need to get back to you on some of the questions asked.

My nieces husband passed away unexpectedly last Thursday.  He was 31, strong as an ox and into fitness.  He was at a fitness camp in California when this happened.  To make it even worse, they are expecting their first baby in November.

Anyway.... I'll answer some of the questions later this week.

 
Ex-Calif said:
I see lots of shading on those panels. Particularly the top half. Are you sure you had full direct sun?

Sun angle and even minor shading will kill your collection. Are you running an moppt controller?

Also flexible panels rarely give out full rating. HueyPilotVN has a setup that would be a lot more predictable/satisfactory.
Click to expand...


The picture does look like it was shaded but it wasn't.  The time of day was 12:00/1:00 and clear sky.  I am running an MPPT controler, Victron Smart 100/50
 
AStravelers said:
What time of day did you take the readings?  Should be around noon sun time (no daylight savings time).

What part of the country were you in?  At the Mexican border or how far north. 

What was the condition of the sky?  Pollution and any haze reduces the output.

Does the Victron show you the voltage and current (and/or watts) at the input to the controller, or were you looking at the output of the controller? 

You have a MPPT controller which works best at higher voltage something like 35-50 volts.  You most likely only have 17-18 volts from individual panels (maybe a bit higher voltage since the panels are supposed to be 200 watts each).  Wiring in series will bring up your voltage to take advantage of the MPPT.
Click to expand...

Time of day was 12:00/1:00, Clear skies and no haze.  We live in WNY, Buffalo area.  The Victron does show input and that's where my numbers came from.  I had all four panels in series and the best I could get out of them was around 270 watts total.  If I remember correctly the voltage was around 67.
 
Tom55555 said:
I'm curious what load you used to check the voltage and amperage for each PV. Did you compare the wattage of all four in series vs. individually / parallel? Before everyone tells me it doesn't matter I understand P=EI. Depending on the hardware used R may vary and if one PV opens in series your system won't charge. You're really better off going parallel from the PVs to the voltage regulator in my opinion.
Click to expand...

I guess the only load I had was charging the batteries.  I have a 600 amp/hr LiPo bank and it was around 85%.  I wired them several ways to get the numbers; 4 in series, 2 series-2 parallel and then each one by themselves.
 
Shading, and the angle at which sunlight hits solar panels are are significant factors. I know several people who have the Victron controller, and they seem to do a good job of monitoring and displaying battery/charge status. Your wire gauge looks good, and I'm assuming there are no bad connections anywhere. So if your panels aren't shaded, and they're within 10 degrees of the sun, I think they're just not putting out what they're rated at putting out. Not surprising considering the type and source of the panels. Sorry

FWIW, we just finished installing six 170 watt Zamp panels on a Newmar Mountain Aire, and the system was putting out 1070 watts at about 3:00 PM, with all the panels tilted toward the sun - two slightly shaded by trees.

Kev
 
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