Renogy 100 Watt 6v panels - really

[fwunder]

I know this may seem strange and I am just a beginner trying to learn, but why would my 200 watt Eclipse suitcase panels be made up of two 100 watt 6v panels? Or rather, maybe it's 4 50 watt panels in parallel/series?

First clue should have been label on one of the panels. See below. Label still doesn't make sense to me. Renogy offers no explanation so far.

Second clue was what sure looks like series connection between panels. This was a mystery. 2 100 Watt panels which look to be hooked in series, but deliver ~20v open circuit voltage. That didn't make sense. I opened the PV junction box thinking maybe there was some kind of shunting going on to make parallel connection. Nope. Straight series and voltage output at each junction box measured ~10 volts! 32 cell, 100 watt 6 volt panels. Seems very, very, strange!!

Does this make any sense? Thanks!

 

[efficientPV]

It is definitely two 6V panels. Bypass diodes are about ever 10V open circuit.. It saves the number of connections that have to be made. Same construction as a full panel.

 

[fwunder]

Thanks for confirming. I wish I knew that when I spent so much money on them. I was hoping to use them as two 12v panels in series w/MPPT controller for longer run from panels to controller. Seems odd that the suitcase is sold as "Two 100 watt Eclipse Solar Panels". I'm guessing most newbies like me would assume two 12v panels. Buyer beware, I guess. Thanks.

 

[Zil]

The label you show is an optimum operation, 18 volt panel with 2 x 2.78 amps. Volts are different than amps.

 

[fwunder]

Thanks Zil. I get that. Seems like an odd label for a 100 watt panel or 200 watt suitcase. The dimensions alone don't match the panel(s). Thanks.

 

[Zil]

Looks like two 50 watt panels. Each <3 amps in parallel for <6 amps at 18 volts. That is 100 watts for the set. I have found Renogy to be one of the honest companies in the solar industry. Seems you have purchased the 100 watt set.

 

[Zil]

Well the photo does show the 100 watt set.

 

[fwunder]

Actually, Zill, the photo and the receipt shows 200 Watt set:

Renogy 200 Watt Eclipse Monocrystalline Solar Suitcase w/o Controller

RNG-KIT-STCS200MB-NC-BC 1 $498.39 USD

Look at the dimensions on the label. My panels measure ~41" x ~21"

Don't get me wrong, these panels do perform. I just did a load test with a 331 watt AC load (wife's hair dryer) via 1500 watt inverter. Battery bank is two one year old 220ah GCs fully charged. Midday sun and panels 12 feet from PWM controller w/ 10 AWG. Panels had no problem keeping up with the load pumping in as much as 11.8 A @ 150+ watts. After ten minutes or so battery voltage measured @ inside panel leveled out @ 12.3v. So, I would say they certainly performed within spec.

My beef is I wanted to get the panels further away from controller without using humongous wire so I planned on buying a MPPT controller and 100 watt series connected 12v panels (which I thought these were). I cannot do that with these panels. Really, that's my beef. Actually, I wish I had come across Will Prowse and his amazing videos before I purchased anything. Would have saved me a lot of money.

 

[tictag]

Looks like they've attached the 2 x 50W set label on the 2 x 100W set. I simple mistake, I guess, but not one that I would ever expect.

My beef is I wanted to get the panels further away from controller without using humongous wire so I planned on buying a MPPT controller and 100 watt series connected 12v panels (which I thought these were). I cannot do that with these panels.

Not sure what you mean here.

It looks like you do in fact have 2 x 100W "12V" panels. You can't take the voltage value from your SCC as the array voltage (Voc) firstly because this is a PWM controller, which means that the array voltage will be dragged down to the battery voltage whilst it is charging and even if it were an MPPT controller, it would vary with solar irradiance levels.

If you unplug your SCC and measure array Voc, I suspect it will say 21.2V, per their website spec.

There's nothing stopping you replacing the Wanderer (PWM) with an MPPT (e.g. Rover).

Am I missing something? Probably!

 

[fwunder]

Hi tictag. I certainly don't claim to be an expert. This is why I am confused...

The "feature" set says "Two 100 watt Eclipse Solar Panels"

If we look at the specs of 100 Watt Eclipse panel we see, Optimum Operating Voltage (Vmp): 17.7V and Open-Circuit Voltage (Voc): 21.2V. That's for one panel.

Yes, you are correct that the specs do read Open-Circuit Voltage: 21.2 V for the suitcase - both panels. Therefore, they are not "Two 100 watt Eclipse Solar Panels". Maybe I am reading wrong or too much into it, but it sure seems two 100 Watt Eclipse panels would perform better @ greater distance from MPPT controller with with smaller gauge wire. That's all.

Yes, I did measure open circuit voltage @ PV junction box and it does measure ~10v.

 

[tictag]

It would be quite unusual for the specs to state Voc = 21.2V but for that to be only one panel, when it is sold as a pair. It is also unusual to measure ~10V when the specs say 21.2V. Are you sure you were measuring open circuit i.e. no SCC connected?

Is it possible that this is two 10.6V panels connected in series for 21.2V array Voc?

 

[fwunder]

Hi tctag. Read efficientPV's post above https://diysolarforum.com/threads/renogy-100-watt-6v-panels-really.9766/post-105638

And from someone much more knowledgeable than me:

Those look to be 5 inch cells which are typically about 3 watts each, so 64 x 3 = 192 walls.

And, your two modules certainly appear to be connected in series, so that would imply that the modules are 6V nominal. Voc (open circuit voltge) of the cells should be around 0.6V so your 10V per module measurement would imply that there is a 16S by 2P series/parallel cell configuration internal to the modules.

 

[tictag]

Looks like I'm joining the conversation half-cocked. Apologies.