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ATESS 100kW HV inverter, 2 x 40/32 FreedomWon HV batteries & 40kW PV Array

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Cables all fished through & that is 9 strings of 14 in series because the ATESS is a 1,000V Solar PV MPPT. 

Only connecting 70 x 575 LONGi Mono Modules here but provision is made for another 56 Panels. Rather fish the wiring through once instead of struggling when expansion is needed. 



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1 hour ago, Steve87 said:

9 strings of 14 in series because the ATESS is a 1,000V Solar PV MPPT. 

Only connecting 70 x 575 LONGi Mono Modules here

@Steve87That is serious dc voltage dangerous can't afford loose connections especially not on the mc4 connectors and in the combiner boxes. Great looking install so far looking forward to the completion pics

Edited by TaliaB
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Thanks guys yes it's really a great project to be a part of. @TaliaByou are spot on in your assessment on the High Voltage MPPT. The battery DC voltage is also 600V & thereabouts but many ppl forget that the Sunsynk 12kW 3 phase machines gets close to these voltages & even the Infinisolar 12kW & 15kW 48V inverter can accept 1,000V DC MPPT input. 

To me at any voltage the DC combiner box must be respected & is probably the most hazardous box in the entire Installation. AC switchgear usually has MCBs & an Earth that helps to get potential down should a fault occur. The DC side is just unfortunately not that forgiving. 

The DC combiner will be quite a massive box & we will wire it ourselves. The AC Grid side called for 120mm2 armoured cable as well as 75mm2 Load Armoured cable. However, the main Eskom Supply only came standard with 35mm2 Cable so we limited to such & therefore will install 35mm2 on the Grid & 70mm2 on the Load. 

The ATESS is like a massive Hybrid that scales very well by up to 4 machines in parallel. They come in 30kW, 50kW, 100kW, 120kW & 150kW. At the solar show they announced a 500kW version. So one.can see that this type of inverter makes a lot of sense for the commercial power operators. 

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The hardest part of the day was the logistics of rigging this 1 ton Behemoth into a small space & even more so doing it on unprepared soft ground below the Forklifts wheels. We got very creative & in the end it worked out very well. But we had a full company of eyes & ears marshalling this kit around to safety. 

Now for the FreedomWon 40/32 twins to arrive next week. Our focus is now on the AC integration & the PV Combiner box. It's a PV Combiner box that most ppl have not seen before. I will definitely take some pics of that box when we build it. 

To say that the ATESS is quality is an understatement. Proper moulded large industrial NOARK MCBs. This is a machine engineered to last & with a 5year warranty that can be extended to 10 years. What's most impressive is how modular the entire machine is. 

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@Bobster.this is a farm that has a 20 odd hectare plant Nursery that runs quite a few bore hole pumps for irrigation as well as a few Air BnB Cottages on the farm. There is also a restaurant as well as a 80kW Generator available. We paired this ATESSInverter with its ATESS ATS (Auto Transfer Switch) it allows seemless use of a Generator integration with the Hybrid system & can be controlled remotely based on battery SoC etc. 

Load peaks can sometimes reach 60kW & the inverter at 100kW & the FreedomWon twins combine to deliver 80kWh so it's a good start in the right direction. The Array size at 40kW will be expanded in the not so far future in fact a couple of months time. 

My concern however, is that FreedomWon have had delays on the batteries mainly because everyone is purchasing the smaller affordable scalable 40/32 HV and they cannot make them fast enough. We have experienced a few delays on these units. However, they have the larger 100/80 & 200/160 units ready almost on shelf. But this is close to 1bar and above BESS (Battery Energy Storage System). 

Also some delays on support with regards to some LV FreedomWon units. Will keep ppl updated on this because looks like the massive pressure to pump units out of the factory has a strain on the other parts of the business like support etc. @PearlJamis one such person that has experienced a problem & they made first contact but are now dead quiet. I will need to take a factory visit to enquire, which is usually never the case. 

What can we say, the Solar industry in SA is running at high capacity but just wish the support & repair infrastructure could be well matched for the volumes pumping out otherwise we are not in a good space. Sunsynk has also had their time in the spot light. I have now waited 2.5 weeks on a 12kW 3 phase damaged unit to be repaired. I have been promised by week 3 all is done. Fingers crossed let's see. 

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14 hours ago, Steve87 said:


Good day @Steve87is that the three-phase unbalance output technology in action like i understand balancing single phase loads on the 3 legs by uising Δ/Y-shaped transformer added between the 3-leg of the inverter and the load. Very impressive well done to you and your team. Seeing forward to the solar combiner box.

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3 hours ago, TaliaB said:

This is the schematic for the three-phase unbalance output technology inverter, the inverter can handle 100% unbalanced loads between phases.


Yes , if you want to entertain unbalanced loads , you need a hard neutral. If your DC side is single ended , then your AC side can only be delta , so you need the magnetics to convert to Y .

If you have a split DC supply , where the midpoint then become neutral , then your three half bridges produce effectively Y configuration without further need of conversion. But at 100 kW it's probably as costly and difficult to entertain the extra magnetics to convert the single battery/pv supply to split supply.

That must be an awfully amount of copper needed  though for that delta to Y conversion, because it's low frequency as well .

One advantage of course is the load is decoupled from any DC.


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