Off grid solar project

[mcart117]

This is a continuation of the thread I started in the introductions forum, and here I shall describe how the project progresses (or doesn't).

The first step is to get the shed roof ready for the solar panals, and to that end I have taken delivery of a box of aluminium ties.



Left over from when a set of old solar panels was removed from my house roof, I also have a box of clamps.



The rails are proving to be a bit more of a problem because you can't just walk into a hardware store and buy them, so I'm still working on that.

At the same time I am talking to a couple of merchants on Alibaba about EVE prismatic LiFePO4 3.2V, 304Ah cells. Andy at the Off-Grid Garage speaks highly of Amy Peng at Shenzhen Qishou, and he has also reviewed products from Shenzhen Basen. So I spoke initially with Amy, but when she said her warehouse was empty, I asked the people at Shenzhen Basen if they had any in stock. They said they did, so I placed an order with them.

That was three weeks ago. Amy still says the warehouse is empty and she has no idea when the factory will deliver some more. Mitty at Shenzhen Basen claims my "goods have been sent to the freight forwarder, waiting for them to ship", but the status on Alibaba is "Waiting for supplier to ship". Under the contract they have seven more days to ship. After that, I can claim a 10% penalty against them. I might even be able to cancel the contract. I'd rather deal with Shenzhen Qishou. I shouldn't have believed Shenzhen Basen when they said they had them in stock, but I was impatient to get some cells to play with.

Anyway, wait and see I guess. I'll report back in a week to say what happens next.

 

[RV10flyer]

This is a continuation of the thread I started in the introductions forum, and here I shall describe how the project progresses (or doesn't).

The first step is to get the shed roof ready for the solar panals, and to that end I have taken delivery of a box of aluminium ties.

View attachment 93576

Left over from when a set of old solar panels was removed from my house roof, I also have a box of clamps.

View attachment 93577

The rails are proving to be a bit more of a problem because you can't just walk into a hardware store and buy them, so I'm still working on that.

At the same time I am talking to a couple of merchants on Alibaba about EVE prismatic LiFePO4 3.2V, 304Ah cells. Andy at the Off-Grid Garage speaks highly of Amy Peng at Shenzhen Qishou, and he has also reviewed products from Shenzhen Basen. So I spoke initially with Amy, but when she said her warehouse was empty, I asked the people at Shenzhen Basen if they had any in stock. They said they did, so I placed an order with them.

That was three weeks ago. Amy still says the warehouse is empty and she has no idea when the factory will deliver some more. Mitty at Shenzhen Basen claims my "goods have been sent to the freight forwarder, waiting for them to ship", but the status on Alibaba is "Waiting for supplier to ship". Under the contract they have seven more days to ship. After that, I can claim a 10% penalty against them. I might even be able to cancel the contract. I'd rather deal with Shenzhen Qishou. I shouldn't have believed Shenzhen Basen when they said they had them in stock, but I was impatient to get some cells to play with.

Anyway, wait and see I guess. I'll report back in a week to say what happens next.

That is why I bought unistrut (steel and aluminum). Easy to attach to steel pipe or pressure treated wood or a roof.

 

[mcart117]

So Shenzhen Basen have reported shipping my cells, which is I hope is a step in the right direction.

The thing is I had asked Amy Peng at Shenzhen Qishou to tell me as soon as new stock came in, and I haven't heard a squeak from her. I hope Shenzhen Basen haven't been rumaging around in people's dustbins, just so they could put something heavy in a bag in time for the shipping deadline.

Wait and see again I guess - this time for 60 days!

 

[mcart117]

My order with Shenzhen Basen is for 4 cells. After an extended discussion on my initial thread about inverters, I have ordered a 24v 5kw inverter, but that means I'll need at least 4 more cells.

There are some really good threads here on battery suppliers, and I wish I'd dug a little deeper before rushing in to place my first order. After reading positive reports on Shenzhen Luyuan, I have opened a conversation with Amy Wan, and she is really helpful and informative. She also seems honest, and admitted straight out that they won't have any of the cells I want for another 10 days. The downside, which others have mentioned, is price. She quoted 33% more more the cells than I paid to Shenzhen Basen. Shipping was about the same.

It may be worth it for greater certainty on the quality of the cells. When I asked her about factory test data, she said "Yes, the cells are with the test data from the original factory (EVE)". When I asked Mitty at Shenzhen Basen the same question he showed a picture of some cells and circled the label on the side of the cell. I don't think that's the same thing, and when I said to him I thought it looked a bit generic, he just said the cells had a 5 year warranty.

So I'll think seriously about the quote from Shenzhen Luyuan.

Meanwhile Andy at the Off-Grid Garage speaks highly of Amy Peng at Shenzhen Qishou, so I prodded her to see if she had any idea when she might have some more in stock, and she replied that she didn't.

 

[mcart117]

Shenzhen Luyuan now have EVE prismatic LiFePO4 3.2V, 304Ah cells in stock. Just for completeness, in the hope of a second quote, I asked Amy Peng at Shenzhen Qishou if she had any, and she didn't.

So I have placed an order for 8 cells with Amy Wan at Shenzhen Luyuan. That will be enough to get me going. Ideally I think I am going to need 16 cells, but I'll start with 8 and take it from there.

 

[Amy Wan]

Thanks for coming back to us. Look forward to your comments after receiving the cells!

 

[mcart117]

Thanks for coming back to us. Look forward to your comments after receiving the cells!

No worries at all. I look forward to receiving them

 

[pollenface]

I've always improvised with hardware when mounting panels. You can usually buy 10ft lengths of Alu anglign which is good enough for me. I don;t care if it's not the same way professional installers do it. I know I can make things handle 70mph winds so all good in my books

 

[mcart117]

I've always improvised with hardware when mounting panels. You can usually buy 10ft lengths of Alu anglign which is good enough for me. I don;t care if it's not the same way professional installers do it. I know I can make things handle 70mph winds so all good in my books

There is a structural problem with the shed roof, and it is really hard to pin down a builder to fix it, so this is what I am doing for now



It might not be able to handle 70 mph winds, but the builder has promised to come soon, and I just want to start testing the battery.

 

[gribbly]

You can usually buy 10ft lengths of Alu anglign

Can you say more about what you mean here?

Googling "Alu anglign" doesn't find anything... I'm currently working on an improvised off-grid panel install and am interested in options!

 

[pollenface]

Can you say more about what you mean here?

Googling "Alu anglign" doesn't find anything...

I've always called it anglign, I guess you could call it an aluminium angle extrusion.

Metal Mate 30 x 30 x 1.5mm 3m Aluminium Angle - Silver

Find Metal Mate 30 x 30 x 1.5mm 3m Aluminium Angle - Silver at Bunnings. Visit your local store for the widest range of products.

www.bunnings.com.au

 

[mcart117]

I've set up a battery test bed.



Check out how nicely balanced the cells are:

 

[wattmatters]

The rails are proving to be a bit more of a problem because you can't just walk into a hardware store and buy them, so I'm still working on that.

How did you go, find any?

I just went to see the installer of my grid-tied PV system. They are pretty regularly removing old small rooftop PV systems for people doing PV upgrades and they generally have lengths of used rails that often just end up going to the recycler.

I made them an offer on some rail they had lying about and they happily delivered. Spend about $100 for what was going to cost $400 delivered. Clenergy rails in good condition and with plenty of feet and extender/connectors and clamps (although I needed a few extras). Turns out I had quite a bit of spare rail as well which will get used one day.

 

[pollenface]

How do you go with mounting rails when setting your panel inclination? Or do you mount your panels on the same angle as the roof?

28.2 degrees true north is my optimal all-year inclination/azimuth (perth, western australia). I wouldn't be sure what to look for to accomplish this when looking at purpose built rails.

 

[wattmatters]

How do you go with mounting rails when setting your panel inclination? Or do you mount your panels on the same angle as the roof?

Most just install panels in line with the angle of the roof.

You can get special racking with adjustable tilts but the installation of tilted arrays comes with additional building installation standards as it creates a much higher rooftop wind loading.

It's more expensive and depending on the roof it may end up being a worse use of roof space because if there are say two rows of panels you now have to have enough space between them so that the front array doesn't case shade on the one behind it.

Usually just whacking up a couple of extra panels makes up for any losses from having "non-optimal" tilt angles and azimuths. And adding a few solar panels is relatively cheap, certainly cheaper than a tilted racking solution would add.

Where it gets tricky is for flat rooftops, usually you want to try and get at least a 10° tilt - it's good for the panels when dealing with rain and self cleaning. Also many panel warranties are voided at less than 10° tilt.

 

[mcart117]

How did you go, find any?

There is an eBay seller: BD Electrics Online. They purport to sell 4.4m rails. So I ordered 4 of them and 2 joiners. The seller knew the rails and the two joiners were being ordered by the same person because I asked him to combine the postage. He agreed to combine the postage but failed to draw my attention to the small print of his description which said: "INTERSTATE Buyers will have delivery cut into 1.1M LENGTHS for delivery requirements". He simply cut them into 1.1m lengths and expected me to make a follow-up order for the additional joiners I'd need. I thought this was pretty deceptive and complained to eBay. They let me print a prepaid postage label to return the rails, but I see the listing is still on eBay, unchanged.

As for the local installer, he agreed to let me have 4 4.4m rails and 2 joiners for $200, but then added $200 for delivery. I don't own a truck or anything similar, so I have left it for now.

 

[mcart117]

How do you go with mounting rails when setting your panel inclination? Or do you mount your panels on the same angle as the roof?

28.2 degrees true north is my optimal all-year inclination/azimuth (perth, western australia). I wouldn't be sure what to look for to accomplish this when looking at purpose built rails.

By coincidence the shed is pretty much on an east-west axis, and the north facing roof has an incline of 28 degrees, so that will work well when I get the rails.

I am located on the same latitude as Perth. Nice to see another Sandgroper on the forum!

 

[pollenface]

By coincidence the shed is pretty much on an east-west axis, and the north facing roof has an incline of 28 degrees, so that will work well when I get the rails.

I am located on the same latitude as Perth. Nice to see another Sandgroper on the forum!

Come for a beer sometime ;p

 

[mcart117]

This chart shows the energy stored in the battery over the first few days of use.

Apart from the first night when I ran it through the night to see how long it would last, I have used it only during the evening peak rate hours from 4-9pm. In this the wettest month of the Oz Winter, my eight 195W panels, leaning up against the shed at an angle of 80º to the horizontal, don't quite generate enough. So at the weekend, when there is no evening peak charge, I have to let the battery idle for a day, to fill right up.

As the days get longer and less cloudy, equilibrium will be restored. Then in a month, there will probably be too much energy for the battery, and I'll be glad of the second bank of cells.

 

[mcart117]

I changed the angles of the panels today, to reflect the change of season (I am still waiting for the builder to fix the shed roof, but I am not chasing him because I am also waiting for the correct joiners for my solar rails). It made quite a differecne to the yield, and the battery went from zero percent:



to 98% (of the 80% capacity I have programmed my BMS to use):



I can't resist repeating how well balanced these cells from Shenzhen Luyuan have remained through many charging and discharging cycles. The battery seems to like the reduction in current from the panels in the late afternoon, but still, a delta of 7 mV is pretty impressive. And I can't resist comparing my screenshots with a couple I took from the OFG (I did try to ask Andy's permission in a post on his thread, but something went wrong and the post was lost):



They say a picture speaks a thousand words: well that one certainly does.

Edit:

Pic sources: OFG1, OFG2