Solar Show and Tell

[Fair_Enough]

Originally Posted by GMFL

I noted same thing after a closer look. Taking it back tomorrow.

Ronnie, I was thinking of the "skin effect" where current flows on the outside of the conductor first, but that is really only an advantage at higher frequencies. Power systems are different. Frequency is actually zero for DC.

20' of 4 AWG copper at 30 amps is a lovely 2.5%, while aluminum is nearly 4%, not so good. The cost savings of using the copper plated cabling is enticing.

If you were to go with a series / parallel panel arrangement, this aluminum would work well, IMO; or you could go to a 2 AWG (clad AL jumper cables) and get under 3% VD... $33 on Amazon. Obviously this larger wire is much harder to run and terminate.

Oh, being "HandyBob Solar" trained, I always plug in 12v nominal on voltage drop calculator not Vmp or Voc.

Clint

[pcskier]

Originally Posted by GMFL

Going to upgrade for 200 watts to 400 watts and ditch the factory 10AWG prewire I’m currently using and shift over to a homemade combiner box and 4AWG wire feeding my Victron 100/30 change controller.

My glee from the performance of my 400 watts on the big trip won you over didn't it? 4 AWG? I would expect nothing less! Where are you putting the combiner?

Also...to run your wire from the fridge compartment under the lounge: The white panel under the lounge cushion is attached with staples. I just carefully pried it off, the staples mostly just pulled through the panel, some stayed in the panel. Removed all the staples, and upon re-assembly, used screws. Quickly gave me full, easy access to the space under the lounge to run wire, without having to take the whole thing apart and remove it.

[GMFL]

Originally Posted by pcskier

My glee from the performance of my 400 watts on the big trip won you over didn't it? 4 AWG? I would expect nothing less! Where are you putting the combiner?

Also...to run your wire from the fridge compartment under the lounge: The white panel under the lounge cushion is attached with staples. I just carefully pried it off, the staples mostly just pulled through the panel, some stayed in the panel. Removed all the staples, and upon re-assembly, used screws. Quickly gave me full, easy access to the space under the lounge to run wire, without having to take the whole thing apart and remove it.

Yup....
Combiner box will go on roof over fridge allowing me access to the microwave space.
I’ve built the guts of the box using a scrap piece of Lexan with some Rivnuts backed with stainless steel washers with are used to bolt on two bonding bars.
I took the jumper cables today a purchased (2) 20’ runs of 4AWG wire which will be my runs between the combiner box and charge controller (with a BlueSea disconnect in between of course)
Going with (4) new Renogy Eclipse 100 watt panels and sticking with my current Victron set up.
Basically I’m just moving everything to a new combiner box and not using the factory prewire for the 400 watt system.
The combiner box will be a NEW addition. I needed a roof penetration anyway for my SureCall install.
The lounge I have removed before so Rivnuts hold it to the wall. It should be easy to remove. And I will also remove the street side dinette seat to access the rest of the solar stuff.
Should be a fun weekend project....

[GMFL]

Originally Posted by Wolfwhistle

Ronnie, I was thinking of the "skin effect" where current flows on the outside of the conductor first, but that is really only an advantage at higher frequencies. Power systems are different. Frequency is actually zero for DC.

20' of 4 AWG copper at 30 amps is a lovely 2.5%, while aluminum is nearly 4%, not so good. The cost savings of using the copper plated cabling is enticing.

If you were to go with a series / parallel panel arrangement, this aluminum would work well, IMO; or you could go to a 2 AWG (clad AL jumper cables) and get under 3% VD... $33 on Amazon. Obviously this larger wire is much harder to run and terminate.

Oh, being "HandyBob Solar" trained, I always plug in 12v nominal on voltage drop calculator not Vmp or Voc.

Clint

Clint,
I’ve got 20’ of 4AWG copper stranded In Red and 20’ of 4AWG copper stranded in black that will be on my delivery truck tomorrow.

[GMFL]

Here are some pics of my home brew roof top combiner box.

[Fair_Enough]

Originally Posted by GMFL

Clint,
I’ve got 20’ of 4AWG copper stranded In Red and 20’ of 4AWG copper stranded in black that will be on my delivery truck tomorrow.

That will be ideal Ronnie.

The run from SCC to combiner is about 18 feet for me. I fished from wardrobe t vent to combiner. Why? because it was the hardest way I could come up with... LOL.

If I remember correctly 4 Eclipse 100W have a potential for 22.8 Amps Imp at 17.7 Volts Vmp.

Doing it all over, I wouldn't use MC4. But then again, I haven't had to shoot trouble up there.

Clint

[Fair_Enough]

Originally Posted by GMFL

Here are some pics of my home brew roof top combiner box.

Looks nice Ronnie. Looks like something an underwater lighting guru would do.
Clint

[AirMiles]

This morning I captured the hairdryer power use profile on my pair of Duracell EGC2 batteries. There was little solar charging happening at the time due to early morning and overcast skies. The hairdryer was set at medium heat and medium fan using the stock Airstream 1000W inverter. Batteries were nearly fully charged based on the 12.86V starting voltage. The hairdryer draws about 750w at that setting which is around 60A at 12.5V. This puts a strain on battery voltage, but the battery voltage recovers quickly after the hairdryer is turned off. My wife uses this hairdryer daily with our solar powered Airstream. Some days voltage can drop to mid-11V range under the hairdryer load if the batteries begin at a lower state of charge.

[GMFL]

Originally Posted by Wolfwhistle

That will be ideal Ronnie.

The run from SCC to combiner is about 18 feet for me. I fished from wardrobe t vent to combiner. Why? because it was the hardest way I could come up with... LOL.

If I remember correctly 4 Eclipse 100W have a potential for 22.8 Amps Imp at 17.7 Volts Vmp.

Doing it all over, I wouldn't use MC4. But then again, I haven't had to shoot trouble up there.

Clint

Clint,
I will be using MC4 connectors between the panels and the combiner box. I’ve got my 20th runs of 4AWG stranded copper for my run from the combiner to the Victron 100/30 solar controller (well the +pos will make a brief stop off at a BlueSea disconnect switch before its connection to the controller).

[AirMiles]

Today I captured the vacuum cleaner’s affect on my EGC2 Batteries. We vacuum clean our Globetrotter vinyl woven flooring several times per day. The Black and Decker Vacuum takes 2A at 120V, which is 20A at 12V when being powered by our stock Airstream 1000W Inverter.

Here’s some pictures. The red line in the power use graph started bouncing around during this test. This happens once every 10 minutes when my Victron 100/50 MPPT controller attempts to find it’s highest output power point. The blue line bounced because we had to move the power cord from a front inverter outlet to a rear inverter outlet. The Black and Decker vacuum works very well and converts to a handheld or upright in seconds. We highly recommend this little vacuum, especially for the new woven flooring. With a power draw of 2A at 120V it’s perfect for using with an inverter on a solar powered Airstream.

[FishByFly]

Does one have to use an even number of panels in a series? When I run the Victron model, 3 panels seem to work.

[GMFL]

Originally Posted by FishByFly

Does one have to use an even number of panels in a series? When I run the Victron model, 3 panels seem to work.

Series is Series. The panels do however need to be the same make, model, and wattage. Just remember for every panel you add to the chain you increase the voltage. 12-24-36-48....... amps stay the same.

And with parallel you increase amps and volts stay the same.

Same goes for batteries.

[FishByFly]

Please continue to be patient with me as I step slowly. Next question.
If I have 3 panels, and wire them I a hybrid series parallel fashion, what mix would provide the best outcome?

[uncle_bob]

Originally Posted by FishByFly

Please continue to be patient with me as I step slowly. Next question.
If I have 3 panels, and wire them I a hybrid series parallel fashion, what mix would provide the best outcome?

Hi

With three panels there is no way to wire them in a hybrid setup. You can either put them all in parallel ( the easy way with stock components) or put them all in series (if your controller will be safe with that max. voltage).

If you had six panels you could wire them up a number of different ways.

1) All parallel
2) All series (voltage .... yikes !!! )
3) three sets of two in series
4) two sets of three in series

Bob

[GMFL]

Here’s a cool post. I did some testing on my “new” Renogy Eclipse 100 watt panels in less than idea conditions. (meter laying on panel covering cells, raining, overcast conditions, Foam corner protectors still on panel covering parts of cells)
Output was still 17.5 volts!

https://www.youtube.com/watch?v=PkxCJC-5DfE

https://www.youtube.com/watch?v=l5vxTXWo_ek

[GMFL]

Originally Posted by FishByFly

Please continue to be patient with me as I step slowly. Next question.
If I have 3 panels, and wire them I a hybrid series parallel fashion, what mix would provide the best outcome?

I’m not sure what you mean. With 3 panels you only have 2 options.
(1) all parallel
(2) all series

If you where to series 2 of the panels and run the 3rd along side parallel the voltages would not match and would not work.

[GMFL]

Originally Posted by GMFL

Here’s a cool post. I did some testing on my “new” Renogy Eclipse 100 watt panels in less than idea conditions. (meter laying on panel covering cells, raining, overcast conditions, Foam corner protectors still on panel covering parts of cells)
Output was still 17.5 volts!

Statement: the output I am measuring is VOLTS not current (AMPS). There was no load on this panels when hooked to the meter.

[CarterKraft]

I found even with the cardboard insert on the panel covering it 100% it was still showing over 14 volts, same as you though no load.

Pretty amazing really getting energy out of what amounts to (in my little mind) a piece of glass.

[Mattirs]

Originally Posted by GMFL

Statement: the output I am measuring is VOLTS not current (AMPS). There was no load on this panels when hooked to the meter.

Solar panels will still put out a high voltage partially shaded, but what drops is the amps.

[Garrygb]

Looks awesome! It's like my solar Prius. Very interesting construction.