Octopus Go or Agile?

anon_ymous

So

I'm getting a 3.2KwH system installed with a battery. I intend on upgrading this to 6.4 KwH in the future, and more batteries. The only thing stopping me from putting more panels on atm is that I need a structural survey and planning permission. Those two are required because I've got a flat roof. I can have 8 panels otherwise 

Given this, I'm not sure what tariff is the best? 

Thanks 

ABrass

Can you describe your PV and battery in more detail? A 3.2 kW system is a bit on the small side these days, especially if you have an EV.

It's a lot more complex having two systems than one larger one, I'd wait on the planning permission.

anon_ymous

ABrass said:

Can you describe your PV and battery in more detail? A 3.2 kW system is a bit on the small side these days, especially if you have an EV.

It's a lot more complex having two systems than one larger one, I'd wait on the planning permission.

Tbh I don't actually have an EV however apparently it was a case of just saying you have an EV? 

Also FWIW, the company in question said they can upsize the inverter now so it's ready to take an extra 8 panels and more batteries in the future. So, I wouldn't be running two separate systems. I'd just be adding to the first

The system is 3.2KwH of 8 x 400w Sharp Panels + a battery ready inverter + one 3.3Kw battery

The inverter can take six batteries, in series and it can handle enough battery power for a further eight panels + five additional batteries 

ABrass

There's a lot of details about expanding the size of a solar system. I would require a lot of details on what inverter they're recommending and how it would be managed with MCS and DNO applications before I'd go for that. For example your 3.68kW inverter might be able to manage 6.4kW of panels but you'd have a lot of clipping.

With a dinky 3.3kWh battery you're probably better off with Agile export. If you wanted to use Go to fill up your battery you'd want/need enough battery to last a typical day of use.

anon_ymous

ABrass said:

There's a lot of details about expanding the size of a solar system. I would require a lot of details on what inverter they're recommending and how it would be managed with MCS and DNO applications before I'd go for that. For example your 3.68kW inverter might be able to manage 6.4kW of panels but you'd have a lot of clipping.

With a dinky 3.3kWh battery you're probably better off with Agile export. If you wanted to use Go to fill up your battery you'd want/need enough battery to last a typical day of use.

So, the inverter they've got there is a

Growatt SPH6000w

In order to facilitate 16 panels and also a further 10kWh of battery storage (give it take)

Also, sorry, clipping? 

ABrass

Clipping is when your panels are exporting more power than your inverter can use. For example I have 8kW of panels connected to a SPH6000.

Because of a split layout I rarely get all my panels fully exposed to the sun, but when they do sometimes I have more than 6kW of power coming in. When that happens I can't convert it and so the extra it is lost. That energy is 'clipped', the term comes from the shape you get on a graph where a smooth curve up has the top clipped off flat.

With up to 6.4kW of panels you would not experience clipping. It is not recommended to have a larger Inverter than your panels for efficiency reasons, but someone else can explain that.

anon_ymous

ABrass said:

Clipping is when your panels are exporting more power than your inverter can use. For example I have 8kW of panels connected to a SPH6000.

Because of a split layout I rarely get all my panels fully exposed to the sun, but when they do sometimes I have more than 6kW of power coming in. When that happens I can't convert it and so the extra it is lost. That energy is 'clipped', the term comes from the shape you get on a graph where a smooth curve up has the top clipped off flat.

With up to 6.4kW of panels you would not experience clipping. It is not recommended to have a larger Inverter than your panels for efficiency reasons, but someone else can explain that.

Thanks 

FWIW, I've decided to get 8 panels "for now" and then the flat roof may or may not need to be reinforced following a structural survey

That's the only reason why I'm getting that inverter. Also, my 8 panels would be west facing or so. The 8 additional would be south facing given they'll be on my flat roof and they'll add beams on

Spies

Why can't you angle them south being a flat roof? 

Alnat1

Makes more sense to me to get the flat roof sorted first and have the whole system installed at the same time. Surely it will work out much cheaper only having the scaffolders/installers/electricians once?

anon_ymous

Spies said:

Why can't you angle them south being a flat roof? 

So, the flat part could be angled south but the rest can't 

QrizB

Worth noting that Octopus have revised their Go and Intelligent rates for new sign-ups in light of the EPG.

• The Go cheap rate is 12p/kWh and they've dropped all the "Go Faster" options.
• For my region, E7 is 14.83p/kWh (but for seven hours, not four).
• Intelligent Octopus hasd a 10p/kWh off-peak rate.

All three tariffs have the same peak rate, 43.37p/kWh in my region, and the same 42.86p/day standing charge.