Ground mounted solar PV installation project

[Kayos]

More gear has arrived. Apart from PV cable, the PV fuses/holders and the battery fuse/isolators arrived.

Here's the Solar fuses and holders, they are the same format as a double MCB, Standard 240v plug fuse for scale. I'll get a 4 way DIN rail box to take them, there's one for each string, the fuses are 15A

View attachment 362663

And the battery fuses and isolators. You pull the handle at the top to pull down the front cover, this cover holds the fuses and opening it pulls the blades of the fuses from the contacts

View attachment 362664

Here's where the fuses go when the cover is closed, fuse removed from cover for visibility,

View attachment 362665

And the fuses in place in the cover. Its a 3 way fuse/isolator but I'm just using the two.

View attachment 362667

It's a bit like a modern version of the big switch used in Frankenstein movies

View attachment 362668

Cheers
Andy

I've seen the top one in lots of kit fed from 16 or 32a suppliesc

 

[brewdexta]

So similar to the old “mcb” style fuseholders?

Battery fuses similar to the old heavy fused isolators ?

I'm not sure, not having used them

When I installed DC in telephone exchanges about 30 years ago, it was all bloody great copper bus bars and fuses you bolted in

I've got the roof of the equipment room well on its way, wall plates, trusses, sarking board and breathable membrane on. I've got the membrane held down with slate laths temporarily. I've decided to go with grey slate, i.e. big sandstone slabs. I'll do that next weekend. I won't post photo's as I don't want this PV thread derailed into a Youtube "how to do a roof" thread

 

[brewdexta]

Just ordered hopefully the final bits of kit. Some trunking, a 4 way DIN rail IP65 case for the Solar PV fuses, An AC 32 amp rotary isolator and 100m of 4mm2 hi-tuff NYY-J cable.

I needed double the 4mm2 cable that I initially thought so I can extend the critical load/EPS interface to house. I haven't thought too much on how this will work in conjunction with the standby generator etc. yet, but I do know it will need to be presented near the consumer unit so while I'm extending the grid connection to the inverter, it makes sense to put this in too.

No doubt there will be other odds and sods, I have to make a door for the equipment room yet, but I don't think it will be much more as I can probably use what I have in the barn.

Cheers
Andy

 

[brewdexta]

Just when you think you ordered everything, you remember some more. Firstly the labels, I bought a couple of sheets

Also, my crimpers were a bit old school so bought a new fangled hydraulic one seeing as I had some 16mm to crimp.

Thirdly I forgot an isolator for the EPS output, the one that you can use to power stuff when the grid goes down. I'll order that later as I also need a few 32mm glands. I'm going to lay all the kit out on the bench as it will be fitted in the equipment shed so I can make sure I have the right size glands and clips.

Fourthly, spare fuses for the battery, they are a bit niche being DC so bought half a dozen spare 100A fuses.

I've nearly finished the roof of the equipment room, one more row of sandstone slates and I just have about enough without cutting this big one up. I thought I had a few more, the missus has been stealing them for stepping stones so I'm recovering them between showers and replacing them with some Indian tiles. As this is not a pitched roof, there are no ridge tiles to finish off the top. I do have some left over sandstone paving slabs that I tried on at the top to finish it off like copings, but it looked carp, so I'm finishing it off with a row of standard tiles but with tops cut square. Having looked at a few privvy roofs on my travels today, as most are not pitched either, that does seem to be the way to do it.

I'm using a newly acquired Erbauer 9" grinder from screwfix to cut them. Works a treat, nicely made, with onw annoying exception. They have altered the spacing on the pin spanner, why? The top is the Erbauer, the bottom one is a generic spanner that fits everything, except the Erbauer

Cheers
Andy

 

[Maker]

Swap it with the nut from your old broken grinder (assuming they didn't change the M14 thread).

 

[brewdexta]

Swap it with the nut from your old broken grinder (assuming they didn't change the M14 thread).

Good call, I bet it's a 14.5mm variable pitch thread I'm in the pub right now, will test it later.

 

[brewdexta]

Just about finished the stone slate roof on the equipment shed. I was struggling to get enough to complete the job, these are the left overs from when the builder did the porch roof so some are pretty shabby, delaminating and widely different thicknesses. But it didn't leak before I put the top course on so should be good enough.

This the second times the tiles have been on, the first time I got the angle of the first course slightly wrong, get that wrong and it all goes to cock.

Just got a few more pegs holes to drill and some mortar to put under a couple of rockers and done.

Then i can start on the door. I'm hoping to get the door frame in and the pits dug for the unistrut base of the panels during this extended weekend as the forecast is good. I can make the door next weekend in the workshop so not weather dependent.

 

[brewdexta]

All my usual avenues of getting a digger and driver in a reasonable time frame have failed. So I'm levelling the site by hand. After a morning of getting roots and rocks out with a mattock , the old concrete base for the LPG tank needed to go as it sticks up out of the profile of the unistrut base.

Scored first with the 9" angle grinder then a friendly chat with several chisels and a sledge hammer.

Seems to be working, its 6" thick so requires a bit of persuasion.

3 more slices to break and done. I'm going to ache tomorrow, I've started already

 

[brewdexta]

Correction, more like 8 to 9" thick.

All split now, just need to get it into the bottom of some gabions before surrounding it with better stone, but that's another project she's dreamt up. I'll be 90 before I get time to potter in the workshop!

 

[brewdexta]

I didn't get chance to do any ground work for the panel ground Mount today, but got a few minutes to shove the battery in the small 19" cabinet.

You can see all the carp in the untidy workshop behind it

I fitted the cage nuts for two more batteries as it's easier sat on the bench than it will be once installed in the solar equipment shed.

I was surprised that it didn't mention supporting the batteries from the back too. I anticipated that and bought some rear supports, cheaper than full shelves and just as good for this.

If I use more than 7.5kWh of batteries I'll get a bigger cabinet.

I hope to get much more done tomorrow. Once I get the posts for the unistrut in, and the post for the catenary wire in place, the rest shouldn't take long....

 

[brewdexta]

Getting closer to installing panels now. This was a pic from this morning where the site has mainly been cleared of turf and roughly levelled out.

Since then I've made a trip to the tip with 30 rubble bags full of stuff from.clearing it, dug three 500mm deep holes, cut some unistrut posts, inserted them into said holes, hooked them up with more unistrut to keep the posts level, and filled the holes with postfix.

Unfortunately, the next step was to go to the pub for copious amounts of Vocation ale with the neighbour so forgot to take a pic.

Well knackered so early bath and bed, hopefully get the hops harvested and 3 more holes dug tomorrow morning. It's my eldest daughter's 16th Monday so going out tomorrow afternoon for food.

 

[brewdexta]

Last 3 posts holes dug and postcrete poured. The iron work is purely to keep the posts at the right angle of the dangle until the postcrete sets. It won't look like that for the panels.

The holes for taller posts are 2 foot deep and have two bags in each, plus a few rocks so not going anywhere.

Next is to take off all the unistrut, final leveling and put some weed membrane down. Then build the unistrut base as it should be with the channel upwards and trim the posts down to size.

 

[brewdexta]

Making a bit of progress. I got the weed membrane down and the full 9.5m length of unistrut base levelled up and bolted a couple of days ago

Today I cut the remaining unistrut to length and started installing it.

I have a feeling that this may only take 10 panels in 5 rows rather than 12 in 6 rows without causing too much shade on the panels behind. I went for a 30 degree angle to start with.

I'm going to get a couple of rows of panels up first. If it only causes shade early in the morning and late at night when the sun is week then I'll squeeze 6 rows in. If not, I'll install 5 rows to start with then add the other two later when I've dug more posts in. During the summer when the sun is higher it shouldn't be a problem. I could also drop the angle a bit more, shade is worse than angle inefficiency

 

[J1nx]

What about leaving the 5 rows like that but adding an array off the side to gather either early morning or evening sunlight?
I rarely use all my solar at peak but I’d really like to get extra hours of useable power. In my case the array is SSW so I’d like to get an SE array in future to gain valuable morning power (swmbo likes to put the washer on, vacuum etc first thing).

 

[brewdexta]

The inverter only takes two strings, and each string will only perform as well as the worst performing panel in that string. So you don't split MPPT strings across different directions. If I had a third string I could. Putting 10 panels on one string and 2 on the other wouldn't work either as I'd exceed the max voltage of the first string.

Using microinverters would work better if you want to have multiple directions. But I have a standard 2 string hybrid inverter. If you use microinverters then you have an "AC" battery i.e. the AC from the microinverters is converted to DC to charge the battery and also to discharge it. And all this has to meet G98, which is doable, Enphase sell them.

For shading, I could look at Tigo optimisers, not sure what they do but cost 50 quid a panel. They proclaim to work with any inverter, and are sold by the same UK distributor as my inverter so worth thinking about.

I still have a bit of reading to do on microinverters and optimisers, trying to get decent technical detail on the system operation rather than a diagram of a wendy house, and the sun is challenging

 

[J1nx]

I’ve looked at some micro inverters on eBay but they hardly inspire confidence.

I’m tempted to just buy a small ‘normal’ inverter such as the growatt 750/1000 and put a couple of panels on that. I’m not sure where a micro becomes a standard inverter, but they will start at 50VDC no problem and be G98 compliant for about £200.

Currently I have one spare panel and one suffering minor shade from a telegraph pole. Shade is an utter waste and although I’ve not used a optimiser I still begrudge any potential left on the table. Infact shading at beginning or end would really frustrate as that power will be 100% utilised.
That’s also the case for extra capacity, I could dump power into my hot water cylinder with an iBoost or similar but what would really help is just extra hours covering base load.

 

[brewdexta]

I've been looking at the Vigo TS4-A-O optimisers more closely. They purport to allow each panel to operate independently and work with your existing inverter (except Huawei and SolarEdge that use their own optimisers) . So with these you could point the panels in the same "string" in different directions. They are £45 in VAT each from Voltacon solar and you need one per panel however they have a duo model that serves two panels if the total output is less than 700w and its the same price. The catch is you need the CCA (cloud controller) and TAP (access point), which is how the kit is monitored and controlled and this is £240 for the pair. The CCA is optional for optimisation but I'm still reading the blurb.

I think this may be a new year upgrade, maybe. It not only deals with shade but with damaged cells etc. and gives you panel level, monitoring. Given that even in strong sun I may not get the full 390 watt per panel due to the latitude, maybe the duo limit of 700w is ok and I can get away with 6 of them. Its something I can add on later, first off get it up an running.

Here's a good explanation of shading, however it doesn't take into account the bypass diodes in most panels, if you look at the menu on the left it has sections on bypass diodes and mismatched panels etc. very nice resource.

 

[Bullet2012]

@brewdexta , thank you for the link, very helpful to a complete novice like myself. Much appreciated

 

[brewdexta]

At lunch time I cut the tops of the posts off flush with the longitudinal unistrut and dropped a couple of bags of post fix into a hole for the post for the catenary wire. So all big bits of cutting and grinding now done, mainly assembly and wiring to do.

If its raining, then I've started a couple of techie projects to monitor used power and the inverter better. First the power monitor. Its uses a 3 port current sensor board from here

I've used a pi4, which is a bit overkill but I may be able to get it to do other stuff too,.

Apart from the three current sensors, it has an AC voltage input, you get an AC wall wart with it. This way it outputs the following

NodeID Realpower1 ApparentPower1 Irms1 Vrms1 PowerFactor1 Realpower2 ApparentPower2 Irms2 Vrms2 PowerFactor2 Realpower3 ApparentPower3 Irms3 Vrms3 PowerFactor3

I'll put one CT on the live to the barn, one on the main incomer and another from the Solar so its an independent source of info. The inverter gives statistics but its nice to have two sources, at least while your checking it all works.

The next one is using a bunch of stuff I haven't used before, it speaks to the Sofar inverter using MQTT https://github.com/cmcgerty/Sofar2mqtt so no need to use the Cloud based app, I hope. I've bought some bits, just need to find some time to solder it all together.

 

[brewdexta]

Seeing as it persisted it down all day around here, I've got the current monitor pi up and running, just the one sensor at the moment.

Here's one line of serial output, only the figures in bold mean anything until I get the other two sensors up and running. This sensor is around the main incomer from the meter.

11 4.34 30.75 0.13 234.76 0.130 5.78 17.32 0.07 235.03 0.289 725.83 997.07 4.25 234.65 0.727

725.83 is real power in watts
997.07 is apparent power in watts
4.25 is the current being consumed in amps
234.65 is the RMS voltage
0.727 is the power factor.

so, I should be able to compare real power with what the meter is reporting, and it should be similar.

With the other two sensors I should be able to track down where those 4 amps are being consumed.

I'm waiting on some M10 channel nuts and some M10 Allen head bolts, so if they don't come tomorrow or if its chucking down again, I'll get the python tools installed and get it sending data into influxdb. I want to get some data in there before I turn on the solar.