Need Advice On Solar Panels For Small Home

[danieltherubin]

Good morning,

Hope everyone is well!

I have a Lux Power SNA5000 & Two Times BX51100 Batteries. 

I have just paid for 4 X 455w solar panels and just trying to find out if it will be sufficient for a small home.

Our electricity bill is about a R1000 a month and our home is a small town house. 

The kettle, coffee machine, micro wave and washing machine is on a change over breaker so that it bypasses the inverter unless we need it so generally it is off during load shedding. 

Our average discharge on both batteries during a two hour load shed is 6% total as we only use the kettle when necessary and then turn the bypass breaker off again.

Would the 4 panels be sufficient enough to keep the batteries topped up and the house going over a load shed the reason for the panels is so that we don't have to be completely reliant on ESKOM if there is ever huge amount of power outages.

Many thanks in advance 

[PsyWulf]

On a sunny day you'll notice the difference

[Bobster.]

It's hard to know what your consumption really is. Can you quote it in units (kWh) per month or per day?

[danieltherubin]

1 hour ago, Bobster. said:

It's hard to know what your consumption really is. Can you quote it in units (kWh) per month or per day?

Hi Bobster, so I have had a look at my COCT bills and I am buying between 400 and 450 units a month that is including the geyser that is not on the inverter. 

Not sure if that's enough to go off? 

 

Many thanks again 
Daniel 

[Bobster.]

59 minutes ago, danieltherubin said:

Hi Bobster, so I have had a look at my COCT bills and I am buying between 400 and 450 units a month that is including the geyser that is not on the inverter. 

Not sure if that's enough to go off? 

 

Many thanks again 
Daniel 

Thanks. So that's a little under what I was using before I switched to solar. I have as much battery as you have, but about 4K of panels. There's some other differences in our situation: we have full gas cooking, a heat pump for heating water (that's on the backed up circuits). I would think that if space and budget permit then the extra panels will allow you a high degree of independence.

Can you configure your system to only discharge the batteries when the grid is down? If so then you may find that the 1.6kW of panels is sufficient. But then you aren't maximising your savings. 

You might also try a Kill-A-Watt or some similar device to identify how much various appliances actually use. I've found, for example, that our dishwasher on the "eco" cycle uses less than 1kWh (about 0.8something) over 3 hours. So that doesn't hurt us very much. The washing machine uses less than 0.5kWh on the cycle we use most often. So these are things that we really don't worry much about now and just use them as we need to. The Kill-A-Watt tells me total and peak load over the time I measure whatever is plugged into it.

You know what the total load is already, but quantifying the individual loads can help you decide what is backed up and what isn't, what you can use during load shedding and what you can't. 

[Bobster.]

Just now, Bobster. said:

You know what the total load is already, but quantifying the individual loads can help you decide what is backed up and what isn't, what you can use during load shedding and what you can't. 

And once you have solar, you want to make as much use of it as you can. So, for EG, we never run the dishwasher at night We try to heat water whilst the sun is up. Max those suckers out! This is another argument more panels. This is how you maximise your savings and your independence.

[FixAMess]

Rule of thumb: Your installed Pv will produce 4-5 x power/day depending on where you live, angle of panels, temp etc. (4 winter, 5 summer)The above is my experience in JHB, CT you may get more. In summer we get rain, kills production, you have winter rainfall so double whammy.

E.g. 1kW panels will produce 4kW power/ day. 

So you will generate, approximately, between 8kWh -10kWh/ day....That's over the entire day, so if all your pv power is going to battery you'll get the above recharged into your battery, ignoring losses.

Someone in CT can maybe share their experience for a more accurate estimate.

Remember, your inverter/panels will only produce enough to satisfy the load, unless your exporting to utility.

[PsyCLown]

I agree with Bobster.

 

The beauty of a solar system is in the panels, I would suggest adding some extra panels to allow for batteries to be charged quicker between loadshedding, especially on days where the weather is not playing along.

Also look at running as many of the appliances as possible during the day to have some more cost savings benefits - even consider adding the geyser onto the inverter and add a smart circuit breaker to have the geyser on a time so it gets heated during the day when the system is idle.

[Eurard]

Agree with all above.

A electronic timer switch is your friend, I have 4 currently.

1. CBI 20A AC feed to the Inverter

2. Geyser

3. Fridge

4. Deep Freeze

 

I set these to utilize as little electricity as required during the evenings, but my Geyser is on during the day, drawing as little as possible from Utility.

Just by doing this I have already cut my bill in more than half.

Next step was bought and ready for install, which was better panels (3kw at least output), and another battery.

When all this is in, I will set my #1 above to switch off at 6pm. I will run off the batteries until 7am next morning. I want to use utility ONLY for when I truly need it, couple days with rain, dark weather and if batteries are not full going into the evening.

There is another very important reason I got that AC timer #1. I have an over under protection before my inverter (I cannot emphasize how important it is to have one), and when it trips due to any V spike from Utility, it remains off in trip status. This switch is then remotely switched off and on again, which resets the over under.

[PsyCLown]

10 minutes ago, Eurard said:

Agree with all above.

A electronic timer switch is your friend, I have 4 currently.

1. CBI 20A AC feed to the Inverter

2. Geyser

3. Fridge

4. Deep Freeze

 

I set these to utilize as little electricity as required during the evenings, but my Geyser is on during the day, drawing as little as possible from Utility.

Just by doing this I have already cut my bill in more than half.

Next step was bought and ready for install, which was better panels (3kw at least output), and another battery.

When all this is in, I will set my #1 above to switch off at 6pm. I will run off the batteries until 7am next morning. I want to use utility ONLY for when I truly need it, couple days with rain, dark weather and if batteries are not full going into the evening.

There is another very important reason I got that AC timer #1. I have an over under protection before my inverter (I cannot emphasize how important it is to have one), and when it trips due to any V spike from Utility, it remains off in trip status. This switch is then remotely switched off and on again, which resets the over under.

This is pretty clever.

 

For interest sake, what do you use for your timers? Sonoff switches?

[Bobster.]

20 hours ago, FixAMess said:

Rule of thumb: Your installed Pv will produce 4-5 x power/day depending on where you live, angle of panels, temp etc. (4 winter, 5 summer)The above is my experience in JHB, CT you may get more. In summer we get rain, kills production, you have winter rainfall so double whammy.

Thanks for this rule of thumb: it is quite handy.

[Eurard]

54 minutes ago, PsyCLown said:

This is pretty clever.

 

For interest sake, what do you use for your timers? Sonoff switches?

CBi Astute - Two DB Breakers and then Two wall plug ones for the Fridge and Freezer.

 

Another nice about the AC DB input to inverter is it shows me what my usage is into the inverter, and with the oven being on eskom, i know how much that is as well.

[FixAMess]

1 hour ago, Eurard said:

. I have an over under protection before my inverter (I cannot emphasize how important it is to have one)

This...

We had an electrical fault in our street, V was sitting at 170V +...

The constant on,off of loadshedding kills elec equipment, so one wonders what it does to the inverter...

[Eurard]

1 hour ago, FixAMess said:

This...

We had an electrical fault in our street, V was sitting at 170V +...

The constant on,off of loadshedding kills elec equipment, so one wonders what it does to the inverter...

Friend did an install and the inverter semi blew up, took it in as he was adamant it wasnt the install.

From the logs it received couple big spikes, and even till today the property through monitoring will run anything between 210V and 270V!