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Grid tied inverter vs Off Grid - Load Shedding in SA


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I have been contemplating disconnecting the Solis Grid tie Inverter and rewiring the Solar panels to divert power to the 2 x Axperts. I have them running as a UPS. Load Shedding is the reason as Grid Tie in SA atm IMO means nothing especially at Stage 4 and during the day when the is sun to be consumed and your GTI is shutdown as a result of a "No Grid" scenario.

Am I doing the right thing ? I don't see things (additional power sources) solutions appearing on the horizon any time soon  in SA.

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13 minutes ago, Louisvdw said:

cannot charge while load shedding is happening

If it was me, I'd probably make me some kind of switching solution. So DC breakers are insanely expensive, but... something I saw in a solar R & D workshop, they actually use a plug and socket method so that PV strings (a few on the roof) can be combined to get different voltages and or different power levels. Occasionally someone forgets to turn off the MPPT before pulling a plug and they pull a nice long flame... but other than that, it works quite well for using the same array for multiple purposes.

Then... simply switch them PV modules over when you really need to.

Or.... get a real inverter and put the Solis on the output. You can even use that nice Hager changeover we all use to only move it there for the duration of load-shedding, or if you really need to move it.

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1 hour ago, flamegrilled said:

I have been contemplating disconnecting the Solis Grid tie Inverter and rewiring the Solar panels to divert power to the 2 x Axperts. I have them running as a UPS. Load Shedding is the reason as Grid Tie in SA atm IMO means nothing especially at Stage 4 and during the day when the is sun to be consumed and your GTI is shutdown as a result of a "No Grid" scenario.

Am I doing the right thing ? I don't see things (additional power sources) solutions appearing on the horizon any time soon  in SA.

Well, need to consider how much is loadshedding affecting you during good sunlight hours. 
 

If I look at the past 2 days, solar production was almost zero in Gauteng, so moving it would not have helped. 
 

I’ve been hearing for years that load shedding is going to get a lot worse and honestly, it hasn’t been that bad. Maybe it’s still to come. We obviously want to get the most out of our systems, but over the past 2 days, I have just ensured my battery is charged from grid and able to handle the loadshedding. This morning I changed it over again to use batteries as there is a little sun. 
 

grid tied will save you money in the long run  while a UPS solution solution will save you some inconvenience when there is loadshedding. 
 

Panels are relatively cheap nowadays, so maybe consider adding some panels onto the Axperts or move some of the Solis. 

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Since I started putting together systems in 2008 to beat the loadshedding problem, I made the assumption that Eskom would be available more often than sunshine. Charging batteries with Eskom makes more sense to me than using solar.

Loadshedding would have to get a heck of a lot worse before Eskom is unreliable for charging batteries. My new house's roof is designed for solar, but I don't think that I would be using it in my lifetime. 

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  • 2 weeks later...
On 2020/09/03 at 9:52 AM, Louisvdw said:

My opinion is that it is not worth while to change it. Grid Tie is quite efficient and it's already installed and working.
It does feel like a waste that you cannot charge while load shedding is happening, but if you do look at the actual numbers it would be not that much.

Good advice rather look at adding a Victron inverter with battery bacup into the mix.

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