Duel axis tracker foundation

[baz0000]

Finally we have had a dry week so concrete was laid today for the two support pipes.

20240510_123451.jpg






























20240510_141905.jpg

[baz0000]

20240609_163943[1].jpg
After returning from holiday I've managed to fit in two full days.

Day 1 was spending 8hrs erecting the metal shed that is supposed to take 2hrs.

Day 2, today, was mounting the tracker poles and running cables from the battery shed to each tracker. Both trackers have a 2 core DC cable for the solar feed and an AC power cable to power the controller and arms. The tracker closest to the shed also has a data cable ready for a TIGO TAP optimizer setup.

Still loads to do.

Run a armour cable from the battery shed to the house.
Place all my assembled stud framing into the battery shed for the inverter, switch gear, PV combiner and consumer unit.
Final fix wiring in the battery shed
Buy in the Fox ESS inverter and battery cube
Assemble and fit the solar panel frames to the top of the tracker poles.

The last one is going to be exciting with 200kg of panels plus frame swinging 10ft off the ground so I'd better do that on a windless day. That's a way off yet.

[baz0000]

Cracking on with the project.

All stud work and first fir electrics installed into the battery shed with combiner box, consumer units and switch gear all wired. An appointed qualified electrician will complete the final fix of the inverter wiring and the incoming (from generator) and outgoing (to house) AC cabling.

20240622_080132[1].jpg

Now onto laying down the house feed with 10mm cable.

20240621_182429[1].jpg

[baz0000]

Another week in and things are starting to take shape with the project. The house mains cable laid, secured along the house run with 80mm masonry screws onto CC8 cleats, the path cutaway reinstated with fresh concrete and ground run filled.

20240629_174428[1].jpg


















































The latter part of the week was assembling tracker 1 solar frame for lifting onto the tracker pole and this was completed today and the two motor arms also added. Next part will be to fit the controller and run the cabling up to the frame level. Once that is complete the frame for tracker 2 will be assembled and installed. Both trackers will then be ready to have the solar panels fitted.

20240629_174202[1].jpg

20240629_174309[1].jpg

[baz0000]

Finished the second tracker frame today ready to lift onto the tracker pole and also completed the to frame wiring on tracker 1 including fixing the controller. Tracker 1 is ready to power up from a generator or home extension to move the frame around during the solar panel install.

To set the frame width I have made two batons that mirror the panel mounting hole span. The lower span is set and frame secured (tightened) then the subsequent pairs will be set as they are fitted.

20240702_083428[1].jpg


















































The completed wiring, to frame level, on tracker one including controller install.

20240702_164457.jpg

[baz0000]

Another day and second frame lifted and first four panels added to tracker 1. The wind started to get quite strong so the day ended early.

20240704_134623[1].jpg

[baz0000]

A fine weather day today so I had a couple of friends over for the final 12 panel install. Not quite health and safety optimal but working off a 1mX1.2m variable height pallet platform worked perfectly.

20240708_105940[1].jpg

































Only leaves wiring the panels up, looping an earth cable around all the clamps and back onto the earth block on the tracker pole. Plus fitting a TIGO TAP to the end of the data cable on Tracker 1.

I still have to buy in the 20kW battery cube and arrange for the electrician to come on site for a day to do the final fix inverter hook up and setup. The end is in sight.

[sdold]

That looks really good, thanks for posting these.

[baz0000]

All the TIGO TS4's have been installed today. The earth wires were run yesterday. It only took around 3hrs. Leaving just the TIGO Tap to wire up then I'm all done. The Tigo installation guide says the order of the wires has no relevance, only that the A B C D order must be the same on both parts; the Tap and CCA. I'll just do them alphabetically to ensure they pair up on each device; blue, brown, green and orange (from memory). The RS485 cable is already prepped ready to terminal fix both ends so that'll be a final 10 minute job.

Once the Tigo Tap and CCA are wired up I'm all done. The 20kw battery Cube is on order and the rest is down to the electrician that I am hiring in for a day.

Project cost:
Two 2 axis Trackers - £3,300
16 500W panels - £1,200
Metal battery shed - £970
Foundation pipes - £950
Concrete (foundation) - £750
Concrete (shed base) - £125
Wood (studwork) - £175
Fixing (bolt, screws, rivets, clamps etc) - £160
AC + DC Switches - £80
DC combiner box - £120
AC consumer unit - £80
Cables DC and AC - £405
Fox ESS 8kw hybrid (single phase) Inverter & TIGO TAP, CCA, TS4's - £2,010
Fox Ec4300 20kw batteries - £6,320
Project tools and trench bucket - £670

Labour:
Electrician - £250

Total Project cost - £17,565

I allowed for £20k but was hoping to bring it in at £17k so there is only a slight overrun.

[baz0000]

The final entry on what has felt like a pretty big project. One that hasn't been a one man job, so help has often had to be called upon. For anyone thinking DIY, do assess beforehand how easy and readily available extra hands are. I was hoping my family would be the main stay but they seemed to be always too busy so the project hinged on coercing my wife in certain tasks but more calling upon friends.

The electrician completed the final fix electrics which included the inverter and battery cube installation. There was a bit of troubleshooting required on on tracker PV output that was only delivering 70V, the other was 360V. The issue was tracked down to one of my connector joints not quite seated correctly at the PV combiner box. Once remedied, both trackers were comfortably over 350V DC.

The 20kw battery cube installed had an initial charge of 52% so the PV output since install has been channelled to charging the battery bank. Presently, it's a heavily overcast day with drizzle so the total output is only hovering at 1kw, meaning that at the time of typing the battery is still charging. Once, the batteries are charged which should be around midday today then the feed to house will be switched on.

20240724_095129[1].jpg
































The battery shed has magnetic PIR LED light strips that are USB rechargeable which work well. The inverter found the home Wi-Fi network easily from the external antenna roughly 60 yards away so the inverter information and battery status are accessed via the Fox Ess cloud app. There is also the TIGO optimizer that is also home networked and gives real time information on each panel output via the Tigo app. The grid/generator infeed has been left disconnected as the initial plan is to run off the solar until the batteries require recharging, then the house will be switched back to mains to allow the PV output to go solely to battery charging.

20240724_094547[1].jpg




























This is the Tracker 1 unit at it's 10am tilt. The controller on this tracker is the master GPS unit with a claimed 6 day without power geo location memory. The tracker runs on two axis and goes flat at the end of the day whilst heading off to the sun facing position just after dawn breaks. Tracker 1 also has the wind speed sensor fitted that will put the tracker into it's safe horizontal position for periods of 10 minutes once a certain wind speed has been met.

20240724_094625[1].jpg
































This is the Tracker 2 unit which has a slave controller which follows the position of tracker 1. They do appear to move in perfect harmony.

20240724_094711[1].jpg
































Both trackers in their mid-morning the sun should be somewhere over there orientation.

THE END!

[baz0000]

The rain has stopped and output has risen to 2.3Kw so I have switched the feed to include the house load. The switchover is fast with PC's and digital clocks on appliances remaining on. The fault notification on the app is because there is no grid/generator backup input voltage detected (unplugged)

19b275d0-939a-4ddf-9b4f-ad295287e560.jpg

[baz0000]

Over a year since the install I figured an update would be useful.

The trackers have proved to be 100% reliable. They wake up every morning and put themselves to bed every evening.

The batteries were encased in a insulation board housing in October 2024, ahead of the cold weather becoming a daily feature. This was an essential task as once the batteries hit 0C they pretty much shut down and in our off grid setup that'd mean a system shut down. A smart glass panel heater was added to the enclosure so the temperature can be set and monitored from an app. I set the heater to 7C which keeps the batteries running fine; at minimum 10C.

The Fox equipment has performed well. There is a +10% allowance on the nominal rating. So the 8kw inverter overloads at 8.9kw, which instigates a safety shut down. The inverter will reboot itself from an overload event. The other shut downs we have experienced has been when the minimum SOC has been reached. In these instances a manual restart is required, this has always required a generator defib on the inverter to spark it back to life as the black start procedure from the batteries has never worked for me. Having written that, this week there was a BMS error shut down on the master that required a restart, this time the battery black start procedure worked but the battery SOC was near 100%. So, maybe you need a higher SOC for a black start?

The Fox equipment is not generator hook up designed or friendly. I raised a thread on the Fox forum and after a year and a few people getting involved a work around to get a working generator hook up was devised. It definitely isn't plug and play but it is possible to charge batteries via a generator feed.

Peak monthly production was near 1mw, with 6mw the full year figure. The solar to mains ratio ranged from 100% solar in May to 15% solar in December. Being off grid there is no feed in which means that once the house load is covered and batteries are at 100% there is 'lost' capacity, or unused capacity available. I calculated that the system could have produced around 20% more electricity on a feed in setting. In reality, the lost production of domestic consumption was on really sunny summer days and on those days the inverter and batteries get very hot, so the throttling back once the batteries reached 100% charge worked well to allow the inverter and batteries low load time to cool down. So the 20% unused capacity estimate is top end as once the equipment gets topping 70C on the inverter and 40C on the batteries then the system will throttle back anyway to protect its circuitry.

Even though this was a DIY build with absolutely no labour install costs or heavy equipment costs associated to the build the economics are marginal. The ROI in year one is 1.9% after factoring in a 15 year depreciation term. This should rise in future years as energy prices rise but will be countered by any maintenance costs that occur. So, as a cost saving investment, it's a meh. I have evaluated ways to upgrade the system to improve the return, another tracker with more panels or extra battery storage and nothing works out. Basically, for us this system as it is pretty optimal on our annual 9mw consumption; two thirds solar, one third mains.

For system monitoring I have moved from the phone app with a 5 minute polling time gap to home assistant HACS integration with 8 second data polling. It's like night and day with near real time data available on the system and any associated smart devices, like out battery enclosure panel heater. I've attached a snapshot of the HA display at 4am that we have on two tablets sat in the windows of two rooms in the house.

Hopefully this thread has provided some useful insight, information and encouragement for people considering a larger scale tracker solution. I look at the trackers doing their thing often and think, quite smugly, I built that.