DIY OG Solar install

lexity

lexity

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I'm a novice when it comes to solar installation, and am helping someone size a solar system which is going be completely off-grid. It's a small 3 bedroom house and they are a couple who have a fairly modest-consumption lifestyle. They use somewhere in the region of 450kwh/month depending on time of year.

They are looking at spending in the region of R100k-120k. They want to know if that could include solar-powered hot water with their existing geyser(150 liters). They would prob leave connection to the grid for hot water if necessary, but knowing them, I'd say they would look for a complete OG solution before very long.

The quote I saw came in at R155k odd but I'm hoping I could do much/some of the labor which would knock around R30 -35k off. Also hoping to shop around with him for components to try to get them the best deal but the quote is for:

2 kW solar(Art), 5.4 kW battery and Deye 5kW inverter. Plus the bits in between.

Hopefully I can get some advice from those with some solar-install mileage under the belt.
 
lexity said:
I'm a novice when it comes to solar installation, and am helping someone size a solar system which is going be completely off-grid. It's a small 3 bedroom house and they are a couple who have a fairly modest-consumption lifestyle. They use somewhere in the region of 450kwh/month depending on time of year.

They are looking at spending in the region of R100k-120k. They want to know if that could include solar-powered hot water with their existing geyser(150 liters). They would prob leave connection to the grid for hot water if necessary, but knowing them, I'd say they would look for a complete OG solution before very long.

The quote I saw came in at R155k odd but I'm hoping I could do much/some of the labor which would knock around R30 -35k off. Also hoping to shop around with him for components to try to get them the best deal but the quote is for:

2 kW solar(Art), 5.4 kW battery and Deye 5kW inverter. Plus the bits in between.

Hopefully I can get some advice from those with some solar-install mileage under the belt.
Click to expand...
Have a look at this thread

Speedster's solar journey

I've been prepping a solar system for my home for quite a while, and have certainly learnt a ton along the way. Over the past 18 months or so I've asked perhaps too many questions (to the great annoyance of some forumites), but I've gleaned enough info to have been confident enough to finally...
mybroadband.co.za mybroadband.co.za
 
With the ultimate goal of going off grid
Questions: how many people in household? How many people need hot water?

Gas stove?

5kW is tricky but not impossible to go off grid for a 3 bed house depending on above answers. It will require more hands on management. Most people would suggest 8kW or 2*5kW invertors.

Not an installer but think you might be able to get away with 100-120k for your proposed install if most of the labour is free and you do some bargain hunting.
Spec everything as per desired off grid system - thicker wire and bigger switches
That is obviously very far from off grid so suggest you increase budget and do the mounting for desired amount of panels as part of phase1. Makes it easier during phase 2 to just be plug and play.
 
Quintrix said:
With the ultimate goal of going off grid
Questions: how many people in household? How many people need hot water?
Click to expand...
Just the two of them on a regular basis.

Quintrix said:
Gas stove?
Click to expand...
They already use gas for cooking. But perhaps they will want to use microwave, too.

Quintrix said:
5kW is tricky but not impossible to go off grid for a 3 bed house depending on above answers. It will require more hands on management. Most people would suggest 8kW or 2*5kW invertors.
Click to expand...
Yes, They aren't high-flyers so are looking to save a bit where poss'. They were thinking of downgrading to a smaller house but where they are the 3 bed houses are quite small.

Quintrix said:
Not an installer but think you might be able to get away with 100-120k for your proposed install if most of the labour is free and you do some bargain hunting.
Spec everything as per desired off grid system - thicker wire and bigger switches
Click to expand...
:thumbsup: I will be learnng as I go.

Quintrix said:
That is obviously very far from off grid so suggest you increase budget and do the mounting for desired amount of panels as part of phase1. Makes it easier during phase 2 to just be plug and play.
Click to expand...
Do you mean the 2kw solar, 5.4 battery, 5kw inverter is far from off grid?

The roof is tiled. Do I have to drill through the tiles to attach the mounting racks to the roofing timber underneath? How does that work?
 
Quintrix said:
With the ultimate goal of going off grid
Questions: how many people in household? How many people need hot water?

Gas stove?

5kW is tricky but not impossible to go off grid for a 3 bed house depending on above answers. It will require more hands on management. Most people would suggest 8kW or 2*5kW invertors.

Not an installer but think you might be able to get away with 100-120k for your proposed install if most of the labour is free and you do some bargain hunting.
Spec everything as per desired off grid system - thicker wire and bigger switches
That is obviously very far from off grid so suggest you increase budget and do the mounting for desired amount of panels as part of phase1. Makes it easier during phase 2 to just be plug and play.
Click to expand...
Off grid isn't really determined by inverter size, it is production capacity and battery. Battery wise you probably need capacity for about 5 days, so 20kWh per day usage requires in the region of 100kWh battery. It is much cheaper to add a small generator to an off grid setup.
 
lexity said:
Just the two of them


Do you mean the 2kW solar 5.4 battery, 5kw inverter is far from off grid?

The roof is tiled. Do I have to drill through the tiles to attach the mounting racks to the roofing timber underneath? How does that work?
Click to expand...


With just the two of them they may get away with a 5kW inverter. 2kw panels is not enough and 5kW batt is too small

The mounting brackets fit "around" the tiles. No drilling through tiles.

There is some good info in Speedster's thread and a few others.
 
Speedster said:
Yes, pretty much.
Click to expand...
Why or how does it not flow up the negative cables and cause a stale mate in the device.

For example, if current flows from the battery's +cable into the inverter via a busbar, would the the same current not flow up the -cable and meet the +cable, in the middle of the inverter?

I must be missing something.

I'm trying to imagine the route taken by the current through out the system, beginning with the solar panels.

I guess I'm expecting the current to be separated from other devices until it's their turn to receive the current.
 
lexity said:
Why or how does it not flow up the negative cables and cause a stale mate in the device.

For example, if current flows from the battery's +cable into the inverter via a busbar, would the the same current not flow up the -cable and meet the +cable, in the middle of the inverter?

I must be missing something.

I'm trying to imagine the route taken by the current through out the system, beginning with the solar panels.

I guess I'm expecting the current to be separated from other devices until it's their turn to receive the current.
Click to expand...
You don't connect positive and negative to the same busbar. In your battery example it is the same as connecting the batteries in parallel with one busbar for positive and one for negative. You'll often have a neutral busbar in a db too.
 
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Speedster said:
You don't connect positive and negative to the same busbar. In your battery example it is the same as connection the batteries in parallel with one busbar for positive and one for negative. You'll often have a neutral busbar in a db too.
Click to expand...
Oh yes, ofc... there are 2 busbars. I remember now from an example setup I saw.

So, whether + or + when it hits the bus bar it just floods all the wires and - clearly - there is no ill effect on anything else connected.
 
I had a question about the efficiency of the inverter.

It is said to be 85% to 90% efficient. I presume this means when current flows in at 100%, by the time it exits the inverter, it is at 85%.

There was someone describing how to work out what size fuse to insert after the inverter, and he described increasing the rating of the fuse.

Why, given the lower amps i.e. 90%, did he have to increase the rating, and not reduce it?

He said the amp rating would need to go up to 196 from 166 due to the inverter efficiency(which I would have thought is deficiency).

His calculation was 166 amps / 85% = 196 amps (resulting in him going for 200amp fuse).

I was expecting 166 x 85% = 141 (perhaps a 150amp fuse)

p.s. his system was a 12v bat, 2000w inverter, 400w panels system.
 
I think I know... he may have been sizing the cable before the inverter i.e. from the battery.

To compensate for the impending loss.

Sorry it may not have been a fuse...


see at 6:13

1688402262102.png
 
RonSwanson said:
TBBH, if you really want to help them, get them to contact a trusted advisor who is in the know, like Steve from PFS.
Click to expand...
Yeah, let lexity rather promote secession and leave normal reality to the professionals.
 
If you're a man you know... we have to at least have a go at mastering something new.

Am I wrong, @Speedster ?

Doesn't mean you can't get help when needed, or even decide to hand it over completely to a professional at some point.

I mean I already know I'm going to need help if we go with those big-ass mf-ing solar panels... 2.2m x 1.1m at 30kg each.
 
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