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Residential Grid-tie Solution in Durban


WJP
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Greetings all

I'm a long time lurker making my 1st post. I'm putting together a solution for my pons of a brother & I'd really appreciate your input. His short term goal is to reduce the monthly bill from Eskom. In the long term they'll progress to hybrid inverters with some lithium base storage. His initial budget to get going is R60,000 all in. I think a grid-tie based system is the way to go given the limited funds. Note there is partial shading on the North facing section of the roof at certain times of day. This is due to a large tree located above the property & is somewhat unavoidable. As he's an architect & has rendered the shading throughout the day to see the effects. I'll post a video of it over the weekend for your interest. I guess we can use both strings on the inverter & split the panels to reduce the negative effects. 

Basic facts:

  • Average daily usage: 38kWh 
  • Single-phase (though he's married)
  • 3 Bedroom home
  • 1 External office 
  • 3 Air conditioners 
  • 1 Pool 
  • Electric Geyser 
  • Gas stove 
  • Electric oven 
  •  A wife that works from home
  • Two power hungry teenagers 
  • Old-school disc meter (not pre-paid)

I made contact with Current Automation DBN & I was quoted the following:

As far as I can tell we'd still need:

  • DC Isolation Switch (though the inverter may have an integrated one)
  • AC Isolation Switch (in addition to the CB on the main DB)
  • 35/40Amp Circuit Breaker (in the main DB for the inverter "input")
  • Earthing/surge protection (must be needed for DBNs climate)
  • Optional WiFi dongle (a nice to have for monitoring)

Obviously we'd get a qualified electrician to complete the important work. Where possible we plan to source the hardware at reasonable prices & install ourselves. Any thoughts on the Ingeteam brand (inverter)? As far as I can recall Italians aren't the best with wiring & electronics. 

 

  • Would a Solis 5kW inverter be a better choice? 
  • Who are good hardware distributors of solar equipment in Durban?
     

 

 

 

 

 

 

 

 

Edited by WJP
Added a question.
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3 hours ago, WJP said:

Please don't all jump in at once.

Bwahahaha. Yeah, I tend to pick and choose. Can't answer 'em all.

On 2020/02/28 at 5:20 PM, WJP said:

Would a Solis 5kW inverter be a better choice? 

No. I don't know the Ingecon either, but I do know the Solis is very much a budget unit, so it is unlikely to be a "better" choice.

On 2020/02/28 at 5:20 PM, WJP said:

Who are good hardware distributors of solar equipment in Durban?

Current Automation is not a bad place to start.

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OK, so lets jump in.....

So to me, the Ingecon looks like a nifty engineered equipment.

However, take note of the following: (potential pitfalls - please chime in if my assumptions are not correct, as i have no experience with this inverter)

1) Adding functionality, e.g. wifi, ethernet etc, needs a bit of pc type knowledge plugging and configuring these systems. I assume the IP configs for Eth & Wifi is buried in the software somewhere, and unless you are familiar with stuff like subnet masks, ip addresses, DHCP, SSID's etc, it may be cumbersome to commission.

2) Personally, the biggest drawback of this (and many other newer generation inverters), is that they where designed for a perfect grid, e.g. USA & Europe. What this means is that when the Grid fails (aka loadshedding here in SA), this inverter shuts down. I don't know why they can't utilise the PV power inline, but hopefully you've noticed the inverter does not have Battery input. And no...you can't connect a battery to the PV + & - inputs (as it has 2 MPPT's), 'cos it needs 900V. The only batteries that are that high voltage is the Telsa ones, + that is not very practical. Maybe one can add a Sunny Island to simulate the grid during grid failure, but that is a extra device, cost, wiring, installation and different management. OK if you are the diy type!. So if you live in a area with perfect grid, then this is a good fit.

3) Not that 6 kW unit is to be sneezed at, but before you pull the trigger, you need to establish what you base, peak loads are. Then you have a good change of getting the correct size inverter.

4) The inverter mentioned does no seem capable of paralleling, (I may be wrong here, as the installation manual does show how to mount multiple units), but there is no diagram to illustrate how to achieve this. So if you are unsure of what your establishment is capable of drawing (peak load), make sure the capability of the inverter can handle those constant loads, or be capable of expansion without a forklift upgrade (add capacity vs discard the old and buy new  $$$$!)

5) Budget permitting, your base/peak load (during the day, which will be high, due to the nature and time of everybody at home, ac's etc), should by covered by the amount of PV installed, plus a bit in reserve. Else you need to split you establishment into critical and non-critical loads. Think geysers/stove. My solution would be to swop out the element to a lower value (1000-2000W) one's, and then control them to use PV power, when it is available. Even if you have to do the switchover manually for now, with automation to be added in future. And NO, Geyerwise is nice, but in 4IR terms, it is ancient. Think HA (Home Automation), IoT (Internet of Things), MQTT (Message Queue Telemetry Transport). Pity Inverter manufacturers have not seen the light yet🥵

6)If you grid does fail whether from age or loadshedding, I would rather look for an inverter that can support a emergency load, and then obviously, a battery backup system.

Feel free to add/delete/improve my take on it.

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