Are these options realistic? (aka 'Rate My Solar Plan' :) )

Magnitio

Brimble said:

Are there particular pros and cons of having two separate inverters rather than one bigger one?

Also would even a 6kw inverter be enough? If the overall PV system is 8.8kw, then a 6kw inverter would be under-sized by 47% (am I calculating that correctly?), it sounds quite a lot, even with the two different arrays having different peaks... How can I estimate the costs / impacts of running a 8.8kw system with a 5kw, 6kw or 7kw inverter, is there any useful online resource for that? (Happy to try to model it myself if I can understand what variables I need to manipulate and how). EDIT: Hold on, this is presumably what Boffinboy24 has suggested I look at )

Lots of questions! I understand from previous posts that smaller inverters can be more efficient when dealing with low power e.g. winter. I'm sure someone more knowledgeable on the subject will comment.

If the panels are generating more than 6kW, a 6kW inverter can output 6kW AC and the rest as DC to the battery. This assumes that it is correctly configured and there is spare battery capacity. Although my setup has 6.4kWp, it is only a very small percentage of time that it produces more than 5.5kW.

Boffinboy24

Brimble said:

Right, this might be tricky but I'll try to explain as best I can (or skip to bottom for ultimate impact

Thanks for sharing! A really thorough approach. What I am curious about is peoples “real” stats - the “how low can you go” thread is worth a read. Most people have their system info in their signature. On cloudy and partly cloudy days, which are frequent, I assume the battery is cycling on and off charging and discharging as sun gets brighter and dimmer . 

If you enjoy the modelling exercises you would probably enjoy a battery and playing with that, so may be worth factoring that in to your sums this is one of the reasons I am still entertaining it. 

ispookie666

I would have to disagree with @Magnitio having split system is still better when you have storage capacity, especially if your battery capacity is lower than your 24hr consumption.  
A split system will ensure you start pulling power from battery later, there by making your battery last longer. 

Magnitio

ispookie666 said:

I would have to disagree with @Magnitio having split system is still better when you have storage capacity, especially if your battery capacity is lower than your 24hr consumption.  
A split system will ensure you start pulling power from battery later, there by making your battery last longer. 

I guess it depends on your circumstances. I would prefer to get the extra output from more southerly-facing panels and spend less on the extra scaffolding, fixings and wiring. Understand that it will provide a little less spread of generation across the day, but with a decent size battery that is less of an issue.

Screwdriva

ispookie666 said:

I would have to disagree with @Magnitio having split system is still better when you have storage capacity, especially if your battery capacity is lower than your 24hr consumption.  
A split system will ensure you start pulling power from battery later, there by making your battery last longer. 

Agree 100%. Not to mention get paid more via Octopus Agile in the later hours when your battery is full

70sbudgie

All my panels face either east or west. And although it is clear that I don't get the peak generation that a lot of other members do, (also impacted by being more northerly), I do feel that I get a higher self consumption ratio (I need to actually number crunch for evidence). Even if we don't generate loads, it is quite exciting to be exporting during the super red period (think I may even have got a bit of the 60p /kWhr rate this week), without having batteries.