Is this solar set up big enough?

Zoomzoom

Zoomzoom

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Looking at solar (again!).

This is what is installed:
  • 4 x Solar Panels
  • 4 x Solar Batteries
  • 5 kw Inverter
  • LED lights throughout.
  • Fridge/Freezer.
  • Gas water heater.
  • Gas stove.
  • LED TV.
I need to add/ have enough power for:

  • charging phones / tablets / laptops x2
  • kitchen appliances (toaster, kettle, blender, bread machine, mixer - not all running at the same time)
  • wifi / modem
  • dvd player
  • washing machine
 
I suspect that you would need to answer the following questions:

Voltage of Inverter (This will be required for loss calcs)
Battery bank voltage and Ah (4 100Ah 12V batteries set up to 48V Inverter is 100Ah Battery) Also type of battery (Deep Cycle, Gel or Lithium)
Solar Panel Watt and Mppt Amp rating, to calc recharge time of battery bank

That being said, I suspect that you would require about 4-6 more panels, and another 4 batteries. Also take note that Washing machine will have to be used when Kettle/Microwave is not running

Apologies for the input, some experts might know better
 
There is a good reason why heating elements are on gas on the current installation.

LED lights, let's say 20 lights, 15*5W and 5* 10W~125W
Fridge~1200W, running wattage~200W

The total power the current system is catering for is about just below 1500 going down to about 525W after the fridge has started.

You can add the cellphones and laptops with no issues on the current system as well as modem and the dvd player.
The kitchen appliances at a rated power of 1000W at a minumum plus the washing machine at about 1200W peak you are looking at adding more than what the current system is capable of providing.

In short I will estimate that you need your setup multiplied by 3. Eight more panels and 8 more batteries.
 
Can people be more specific about which batteries and which panels? It is becoming increasingly complex to figure out what to buy, and which brand.
Also, a real world example would help, like what are you guys running at home at the moment, and how do you calculate what and how much batteries and panels you need.
 
CamiKaze said:
Can people be more specific about which batteries and which panels? It is becoming increasingly complex to figure out what to buy, and which brand.
Also, a real world example would help, like what are you guys running at home at the moment, and how do you calculate what and how much batteries and panels you need.
Click to expand...
You mean those advising or those asking questions? Those asking are mostly clueless and those advising are mostly not experts so it becomes a little bit complicated.
 
I have just pulled the trigger on a solar backup/self consumption system.
The requirements were as follows:
- Enough battery to run most of the household for 4 hours during loadshedding. Given average load is 2kw, this means 8-10kwh of USABLE battery capacity. This means taking into account cycle depth etc.
- Powerful enough inverter to run most of the household without having to stress about overloading. This was constrained by cost and available inverter sizing - I was unable to go towards an 8kva in the brand I want.
- Enough solar capacity to charge the batteries during the day if we run them down overnight doing self consumption. The availability of 100% DoD batteries with warranties in the thousands of cycles has led to this being practical
- Integration with my home assistant system because I'm a nerd like that.

So the spec has come out at a 5000KVA inverter (rated 4KW continuous, with peak of 10KW.
10kwh of BYD LiFePo 100% DoD batteries
10 330W panels
250V/70 Amp MPPT, Victron Venus controller, sundry other bits and pieces.

Cost is around R180k.

80k of that is the batteries - they really are the key to this- their 100% DoD with thousands of cycles means you can practically store solar energy during the day and use it at night. If you do the same with traditional lead based batteries, you can only expect 500-1000 cycles depending how low you discharge them before you need to look at replacing.
Deep cycle lead is only good for at most 50% DoD (depth of discharge), so if you have 200 amp-hours at 12v, that's equivalent to 2.4kwh total capacity, but only half of that practically usable - and even then, the lifespan is limited. They'll work for load-shedding backup but you will not be able to use them for self-consumption of excess solar power generated during the day.

Panels are about 1800 each. 3.3kw should give me around 20kwh of generation per day, which would first be used to charge the batteries from last night, and then would be used to power the house and minimise draw from the grid. At night, the grid draw would be kept low by running off battery power.
The inverter has multiple preset modes - eg self-consumption or backup. In backup mode it will keep the batteries at 100%, with increased reliance on the grid for normal operation- so when load shedding is imminent, just push a button to activate this mode so that an 8am load shedding slot doesn't hit me with batteries already depleted from a night's usage. Then when the system stabilises, back into self-consumption mode to minimise grid usage. It can also backfeed, should City Power decide that they want to encourage this and offer decent money - but I'm not planning for this at this point.

I know this post doesn't directly answer your questions but hopefully it can guide your thinking towards what's achievable?
 
thechamp said:
There is a good reason why heating elements are on gas on the current installation.

LED lights, let's say 20 lights, 15*5W and 5* 10W~125W
Fridge~1200W, running wattage~200W

The total power the current system is catering for is about just below 1500 going down to about 525W after the fridge has started.

You can add the cellphones and laptops with no issues on the current system as well as modem and the dvd player.
The kitchen appliances at a rated power of 1000W at a minumum plus the washing machine at about 1200W peak you are looking at adding more than what the current system is capable of providing.

In short I will estimate that you need your setup multiplied by 3. Eight more panels and 8 more batteries.
Click to expand...
Won't a 5kW inverter be enough. Adding up all the watts you calculated coming up at 3,7kW. Or is there something I'm missing?
 
smkungfu said:
Won't a 5kW inverter be enough. Adding up all the watts you calculated coming up at 3,7kW. Or is there something I'm missing?
Click to expand...
True, that is why I ommited it, just the panels and the batteries, but I see that I should have been explicit about it.
 
This is on a converted container home advertised as being totally off-grid, rainwater collection / solar installed etc. Was worried it wasn't big enough to actually run a normal house usage every day, all day. I work from home, and have a computer running nearly all day, as well as needing to do all the usual household stuff. I REFUSE to go back to not having a washing machine. Life is not worth living without one. I'll forego the microwave to have a washing machine!

I think you guys have answered that question - it probably isn't.
 
Zoomzoom said:
This is on a converted container home advertised as being totally off-grid, rainwater collection / solar installed etc. Was worried it wasn't big enough to actually run a normal house every day, all day.

I think you guys have answered that question - it probably isn't.
Click to expand...

A normal house is very much of a "how long is a piece of string" question.
What is your monthly usage?
 
Zoomzoom said:
Around 300 KW but that includes the blinking geyser.
Click to expand...

Very low usage actually, especially with a geyser. Mine is 1000kwh per month with no geyser.

So on average 10kwh per day. You'd need probably 12kwh per day of solar generation capacity in midwinter to go completely off grid. Also probably in the region of 12kwh of battery storage - more to give you a buffer for cloudy days... The battery is really the expensive part. You don't need to go completely off though, in order to start saving money - but to be honest your bill is so low that at this point it will be quite hard to make a return on your investment in financial terms.
What's your driver/motivator at this point?
 
Sinbad said:
I have just pulled the trigger on a solar backup/self consumption system.
The requirements were as follows:
- Enough battery to run most of the household for 4 hours during loadshedding. Given average load is 2kw, this means 8-10kwh of USABLE battery capacity. This means taking into account cycle depth etc.
- Powerful enough inverter to run most of the household without having to stress about overloading. This was constrained by cost and available inverter sizing - I was unable to go towards an 8kva in the brand I want.
- Enough solar capacity to charge the batteries during the day if we run them down overnight doing self consumption. The availability of 100% DoD batteries with warranties in the thousands of cycles has led to this being practical
- Integration with my home assistant system because I'm a nerd like that.

So the spec has come out at a 5000KVA inverter (rated 4KW continuous, with peak of 10KW.
10kwh of BYD LiFePo 100% DoD batteries
10 330W panels
250V/70 Amp MPPT, Victron Venus controller, sundry other bits and pieces.

Cost is around R180k.

80k of that is the batteries - they really are the key to this- their 100% DoD with thousands of cycles means you can practically store solar energy during the day and use it at night. If you do the same with traditional lead based batteries, you can only expect 500-1000 cycles depending how low you discharge them before you need to look at replacing.
Deep cycle lead is only good for at most 50% DoD (depth of discharge), so if you have 200 amp-hours at 12v, that's equivalent to 2.4kwh total capacity, but only half of that practically usable - and even then, the lifespan is limited. They'll work for load-shedding backup but you will not be able to use them for self-consumption of excess solar power generated during the day.

Panels are about 1800 each. 3.3kw should give me around 20kwh of generation per day, which would first be used to charge the batteries from last night, and then would be used to power the house and minimise draw from the grid. At night, the grid draw would be kept low by running off battery power.
The inverter has multiple preset modes - eg self-consumption or backup. In backup mode it will keep the batteries at 100%, with increased reliance on the grid for normal operation- so when load shedding is imminent, just push a button to activate this mode so that an 8am load shedding slot doesn't hit me with batteries already depleted from a night's usage. Then when the system stabilises, back into self-consumption mode to minimise grid usage. It can also backfeed, should City Power decide that they want to encourage this and offer decent money - but I'm not planning for this at this point.

I know this post doesn't directly answer your questions but hopefully it can guide your thinking towards what's achievable?
Click to expand...

Yep, I have also just pulled the trigger on solar as well

Just waiting for installation date for the whole system to get connected up to the house.

Got a solar conversion pack for our geyser
Then starting off with

9 x 260 Watt solar panels
Victron 5000Va easysolar inverter
Pylontech 5.9KWH Lithium Ion Battery
and then all the bits and pieces with it.

cost us about R150K for all of it and the idea was to do exactly what you mentioned for loadshedding and energy saving from Eskom

I want to see how much this takes me off the grid and then depending on how it goes I may just pull the trigger to increase the amount of panels and battery power to try and get completely off the grid, but instead of spending it now I will rather wait and see what I need to do this.

I currently use about 25-30 Kilowatts a day but that is also with the geyser so once that gets moved over to solar I may be able to be close to my consumption with my current setup.
 
you guys use way to much electricity. i buy 166 units every month for R350 and not a Watt more, ever. !
I switch my geyser on when i wake up and i switch it off an hr later.
 
Sinbad said:
Very low usage actually, especially with a geyser. Mine is 1000kwh per month with no geyser.

So on average 10kwh per day. You'd need probably 12kwh per day of solar generation capacity in midwinter to go completely off grid. Also probably in the region of 12kwh of battery storage - more to give you a buffer for cloudy days... The battery is really the expensive part. You don't need to go completely off though, in order to start saving money - but to be honest your bill is so low that at this point it will be quite hard to make a return on your investment in financial terms.
What's your driver/motivator at this point?
Click to expand...

Lots of things. Because this is basically a plug and play house. They come, put it down, you move in, switch it on, it might be the only way I can afford to move to the town I want to move to. Even with buying a plot it works out within my budget (and I get a brand new house, with brand new appliances the works) while houses in the area are out of my budget. The only problem is that it is still at the limit of my budget so I can't really be adding another R50K (or more) of this and that to make it workable.

Because while my consumption is low, I can't afford more and the coming increases are scaring the .... out of me. And I just have nowhere left to trim my consumption.

ESKOM blackouts give me the sh.....ts!! I'm so DONE with it! It is SO disruptive to my day - it just is so miserable trying to work around the gaps in electricity. So there is a 'f-ck Eskom' element to this.
 
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