Balcony solar 200W, grid-tied

[Jordi]

I would like to share with you my balcony solar installation after 1 month of use.
It shows that solar is potentially feasible in cities or rented homes If placed on balconies and it is fairly simple.

Material:
- 2x100W flexible solar panels (16V, 32 cells)
- 600W MPPT grid-tied inverter (range: 22-60V)
- DCM meter (PZEM-15)
- 1,5mm2 copper cables
- Wood planks
- Plastic cable binders

Photos:







Description:
The installation is composed of two 100W flexible solar panels that weight around 2,1kg each and hang on the outer side of the balcony railings with a wooden self-made structure. The main concern at design phase was the weight of the panels and so risk prevention; they could fall. The panels are 16V (32 cells) solar panels specially selected to minimize weight and costs. A hard glass panel would give better yields but weight too much (100W: 8kg approx. each).

The wooden structure is raw would with two coatings of white paint for humidity protection. The wood is bonded with water resistant glue, then metallic screws and in specific location with elbows too. It is designed so the weight of the panels lay on the balcony railings. Since the weight is supported by the railing, I just use cable binders to fix the structure. The structure survived winds of up to 110km/h with wind gusts of up to 130km/h; that was Eunice storm.

The panels are connected in series and the 1,5mm2 cables pass through the balcony door which does not close tight and thus allow two cables to sneak in. If that was a problem, then the installation would only operate in spring, summer or so long the door may stay open without freezing the place.

Output:
The max. output in the Netherlands around March is: 0,5kWh per day

- Orientation of the panels is West (azimuth 266) and the sun starts hitting the panels over the midday around 13h. or later. The building shadows the panels in the morning.
- The panels are from Aliexpress and customers have reported a max. output of 70W per panel. I personally have not seen anything higher than 55W per panel.



The yield of the grid-tied inverter is low (80-85%); however up to now I have had a little reduction on my monthly energy bill and delivered 5kWh surplus to the grid which will be discounted from my yearly balance (net metering).

 

[Jordi]

Seeing that this is the biggest installation I have ever built and that due to my status of renter I can not do much more in my house.
Could you please brainstorm a few proposals on what to do for a next project?

I feel like since I can not find what to do next, my learning process suddenly makes less sense. Is there something I could aim for as explorative project and that I also can use. What I miss from this installation is the possibility to have off-grid section in the house or utilize heavy consumers like heaters; but that all requires more production.

Maybe I can add more panels? Dig into panels output/pricing and replace the installation for bigger ones? Keep learning on balcony structures? Try a commercial approach?

Please I welcome ideas.

 

[MisterSandals]

Could you please brainstorm a few proposals on what to do for a next project?

I propose that you make it less of a fire hazard. And perhaps more importantly to anybody
who is working on the grid, that you implement a rapid shut down in case of grid failure (at the very very minimum) so
a linesman isn't killed by your back feed.

 

[meetyg]

I propose that you make it less of a fire hazard. And perhaps more importantly to anybody
who is working on the grid, that you implement a rapid shut down in case of grid failure (at the very very minimum) so
a linesman isn't killed by your back feed.

I think that the inverter he's using should have an anti-islanding feature. But it's always a good idea to double check.

OP: You can check by using an AC voltage meter/ Digital multi meter set on AC voltage. Check the prongs of the inverter (AC side) when it's connected to solar, but disconnected from the grid. You shouldn't have any voltage. If you do, then the inverter doesn't have anti-islanding, and you really shouldn't use it, as it is a risk to you and others.

 

[WYtreasure]

Please I welcome ideas.

The two previous posts are worth reading and addressing.

I also have ideas. I hope you like my ideas, they are safety related.

1) Remove the panels from the railing. The railing is not designed to support the weight nor is it designed to withstand the added wind load caused by the panels and wood.

2) Use proper connections. Ring terminals should have a properly sized hole for the stud to which they are mounted. Ring terminals should lay flat to the surface to which they are transferring loads to or from. Flat washers, lock washers and nuts should be of the proper size and made of the proper materials. Nuts should be able to be tightened to the proper torque without any of the (nut) threads being visible.


3) Eliminate exposed wire. When connecting wire to a terminal there should be no visible wire outside of the terminal.


4) What is the white discoloration on the top of the battery?


I think it is just a matter of time before your landlord tells you to remove the panels or they fall.

Good luck.

 

[ejfluhr]

I like the approach (doing what you can in the space you have), agree that safety can and should be double-checked & enhanced if needed. W.r.t. railing-based attachment, it may be better to use metal hose clamps instead of plastic ties. Whether or not the existing railing can adequately support the panels seems difficult to judge fairly from pictures alone. However, now that the idea is proven, maybe you can build an alternate mount that achieves similar solar effectiveness without hanging off the railing. And/or implement a pivot so it can be adjusted between flat & vertical for better collection mid-day versus late-day.

Ikea batteries are just used to run the shunt?

For future learning: battery storage, if you don't already have it? Given the insanity currently going on there in Ukraine, it seems prudent to me to have self-generating backup in case of extended power outage, e.g. to run lights, cellphone, computer, maybe TV, maybe refrigerator. Sure, 0.5kWh/day peak isn't going to win any competitions, but that is infinitely better than 0kWh/day.

 

[WYtreasure]

I like the approach (doing what you can in the space you have), agree that safety can and should be double-checked & enhanced if needed.

I agree, do what you can with the space available.
Those panels could do just fine on the patio. In fact, they could probably do even better because they could be pointed in the direction of the sun.
Solar panels produce much more power when aligned properly.

 

[Bud Martin]

You must have a very nice landlord that allow you to do that.
I would not not depend on those nylon cable ties for mounting the panels. Are the cable ties rated for UV protection? They will become brittle when exposed to Sun for a long period of time.

 

[Jordi]

Thank you for all the comments. Is not really what I was hoping for but it will certainly give me some to-do's for now.

Part of the safety issues were addressed over the last weeks. Photos were made shortly after placing the installation.

I will work on cabling and removal of flammable items. The inverter itself is safe (as I could test); the shunt immediately goes to VOC and zero current when disconnecting the AC side. What regards to the structure; the cable ties are UV sensitive but should resist for 1 year; the idea is to replace them from time to time and eventually buy the metallic replacement. The cable tires do not support the full weight of the panel; the weight mostly rest on the railing and the ties keep it fixed to that position.

Placing the 2 panels on the railings is not an issue. Metallic railings on a balcony are meant to hold human weight; at least the half of one person; 40kg. If that is not the case I prefer solar panels to be the test subject and not me. Placing 5kg of permanent weight is neither a problem thanks to the non-elastic behavior of metal (2kg per panel + 0,5kg for the mount). To start talking about plastic deformation I should put 80% of the maximum allowable weight over a few years. The neighbors association has the right to ask me to remove the panels, but advantages of living in a trashy location is that nobody cares.

Further from the safety improvements, I am still left with what to do next.

ejfluhr​

For future learning: battery storage, if you don't already have it? Given the insanity currently going on there in Ukraine, it seems prudent to me to have self-generating backup in case of extended power outage, e.g. to run lights, cellphone, computer, maybe TV, maybe refrigerator. Sure, 0.5kWh/day peak isn't going to win any competitions, but that is infinitely better than 0kWh/day.

I have a 0,75kWh LiFePo4 battery with Daly BMS. I use this battery for off-grid tests and learning about balancing, etc... What I see in the battery direction (and possible project for this year) is having a grid tied inverter with the battery so I can shift solar output to the evening. My stop here is the costs of such inverter (>200 euros), the need of changing the electric installation of my rented house, the increased risks with batteries, the low solar production I have and the low battery capacity of my current battery. But actually my research can be finding a solution to that.

 

[Jordi]

Dear all, I would like to update you with the output of this 200W balcony setup for the ones that are considering it as a possibility for their place.

I have accumulated in the 3 best quarters of the years for solar around 120Kwh DC to be transformed into AC, used at my place and eventually be injected to the grid.


I note down on a paper the daily output to later make this excel graph and sometimes either forget or can't register it, therefore you see gaps.

Winter in North Europe is really bad for solar, not expecting more than 15Kwh for the 3 missing months.