Solar Panels- are more panels always better?

[RyanBM]

Hi

I am about to pull the trigger on installing panels.

My current backup system is 6kw Voltronic Axpert and 5kw Narada.

I have no heat generating appliances connected to the system, so my daily draw is rather minimal (no I have not measured this- its purely an anecdotal estimation)

 

My options on the panels are as follows:

6x 550w Canadian, or

12x 445 Canadian

 

The objectives:

1) in the event of a black out and the grid going down, having the means to be functional

2) as the panels will be in place- to derive some daily benefit by powering basic daylight loads and charging the battery for load shedding.

 

Thanks in advance.

 

[mzezman]

Just check that your MPPT can handle the volts of those panels, esp the 550w ones

Always good to get more as on lower production days you know you are covered. 

[RyanBM]

This is what the installer said:

In order to place 12 panels on your roof, some of them would need to face a different direction. Meaning they will produce different levels of power depending on the time of day. You will always have the situation where one set will cause the overall power to be reduced. This can be overcome by using an inverter with 2 MPPT inputs. Your inverter only has one input however.
 

If we add more panels on the south facing roof but on the same mppt, the south facing panels will cause the total production to drop significantly during winter as they will take power from the north facing panels.
 

[cbrunsdon]

Another option is to go for the 12 panels but keeps those on the south roof dark as part of future expansion through a new/second inverter.

It is just a set of wires run from this second string once you want to go live with them.

A second battery would also be beneficial with a smaller set of panels. You want to harvest the power when it shines and with nothing extra to store it, it really is a waste. I have that problem with a single 5Kw block and 10x455W panels on sunny days.

[GreenFields]

26 minutes ago, RyanBM said:

This is what the installer said:

In order to place 12 panels on your roof, some of them would need to face a different direction. Meaning they will produce different levels of power depending on the time of day. You will always have the situation where one set will cause the overall power to be reduced. This can be overcome by using an inverter with 2 MPPT inputs. Your inverter only has one input however.
 

If we add more panels on the south facing roof but on the same mppt, the south facing panels will cause the total production to drop significantly during winter as they will take power from the north facing panels.
 

Don't put panels in a South-facing direction if you can avoid it, even if you get an inverter with a 2nd MPPT. The best really is to face North. On a sunny day the 6 panels are enough to charge the single 5kWh battery and provide for a basic amount of household loads. On a dark cloudy day you probably won't have enough solar, but double the amount of panels also won't make up for an 80% loss of power anyway. Some folks will say you can never have enough panels, but it's a case of diminishing returns.

[RyanBM]

Thank you Gents- I’m going to go with 6x on the North Roof.

I’ll report back on how I go.

[RyanBM]

So I finally had panels installed- to recap my system:

1x 6kw Axpert King

1x 5kw Narada Lithium 

7x JA Solar panels

Attached is what I’ve noted anecdotally- 

Now I don’t know if this is good, bad or average. 
 

Any thoughts?

[Proff72]

21 minutes ago, RyanBM said:

So I finally had panels installed- to recap my system:

1x 6kw Axpert King

1x 5kw Narada Lithium 

7x JA Solar panels

Attached is what I’ve noted anecdotally- 

Now I don’t know if this is good, bad or average. 
 

Any thoughts?

Hi
Not sure what size panels you fitted but if they are around 550W you should get max 3.85kW. Getting 3.2kW this time of the year is fairly good.
I also went for the larger wattage panels - they take up less roof space.

[RyanBM]

Yes they are 550w panels 

[spotity]

I have 8x545 average of around 3.5kW in winter, facing north. 3.2kW is good for this time of year on 7 panels.  

[Bobster.]

My 5c. I have 4kW of panels, half facing North, half East. On a sunny day everything is good. But sometimes I feel like getting some more panels so that my production on overcast days increases. 

On a sunny day, the extra panels would never produce full power, but on an overcast day I will get more off the roof and into the battery.

[Sc00bs]

@Bobster. I agree 100%, the same applies for Winter/Summer.

If you have enough panels to give you sufficient power through winter, you are going to be having LOADS of power come summer. 

Are you "wasting" power? I don't think so but you will be getting smaller returns on your investment. 

Unless there is something that you could use the excess available power for on those high availability days, I suppose it really is lost. 

I was contemplating making my own hydrogen gas, but it is notoriously difficult to handle due to the very small molecule size and explosions are an issue!

To make it easier to handle, have pondered SNG ( synthetic natural gas), another advantage advantage would be that I could use my existing gas appliances & heaters.

Production of CH4 involves using the Hydrogen  from the electrolysis process and combining it with a  Carbon molecule from CO2 using a Methanation reaction using a nickel catalyst.  

Trying to find a chemistry major to make me a small plant for energy storage but until then I am just heating up my swimming pool with excess energy  

[spotity]

4 hours ago, Bobster. said:

My 5c. I have 4kW of panels, half facing North, half East. On a sunny day everything is good. But sometimes I feel like getting some more panels so that my production on overcast days increases. 

On a sunny day, the extra panels would never produce full power, but on an overcast day I will get more off the roof and into the battery.

Completely agree, on a good day, I only use 3 hours at "full capacity", in summer it'll be even less. I heat water most of the time with the excess power or heat up the house with the AC's and run my pool for 6 hours a day. 

On the overcast days, I prioritize the loads to the minimum, I do plan on adding extra panels to make this less noticeable, but they will be idle on good solar days.