Energy

Katebero1

Hi, I have 11 solar panels, no feed in tariff. I have an electric car but not a model that Octopus accepts, so I instead of 7 off peak hours, I get 4. I am purchasing a 10kw battery to charge with excess from the solar and charge off peak. I see no point selling my excess for 3p/kWh and the being charged 28p/kWh at night. My current bills are £37 per month but I have underfloor heating in a very insulated house. I'm hoping that with the battery, I'll always be running on 7.5p/kWh maximum.

Mstty

Katebero1 said:

Hi, I have 11 solar panels, no feed in tariff. I have an electric car but not a model that Octopus accepts, so I instead of 7 off peak hours, I get 4. I am purchasing a 10kw battery to charge with excess from the solar and charge off peak. I see no point selling my excess for 3p/kWh and the being charged 28p/kWh at night. My current bills are £37 per month but I have underfloor heating in a very insulated house. I'm hoping that with the battery, I'll always be running on 7.5p/kWh maximum.

You won't get much battery charge in winter from solar when you need your underfloor heating the most but at this time of year you should be running at a very low cost👍

[Deleted User]

Katebero1 said:

Hi, I have 11 solar panels, no feed in tariff. I have an electric car but not a model that Octopus accepts, so I instead of 7 off peak hours, I get 4. I am purchasing a 10kw battery to charge with excess from the solar and charge off peak. I see no point selling my excess for 3p/kWh and the being charged 28p/kWh at night. My current bills are £37 per month but I have underfloor heating in a very insulated house. I'm hoping that with the battery, I'll always be running on 7.5p/kWh maximum.

Octopus accepts all EVs and PHEVs; however, not all EVs/PHEVs are compatible with Octopus’ Intelligent tariff. I have a BMW that I charge overnight on Octopus Go Faster (5 hours off peak).

Batteries suffer from transmission loss so 10kWh of storage doesn’t give 10kWh out. I struggle to see how a 10kWh battery will you give you sufficient output to power underfloor heating on a cold Winter’s day without Grid use. I have a large solar array (20 panels) and my worst day last December was 350Wh.

QrizB

Mind if I break this down?

Katebero1 said:

Hi, I have 11 solar panels, no feed in tariff.

OK, if you don't have a FIT I guess this is a faily recent installation? Those 11 panels, are they 300W each? If so, that's 3.3kWp and a typical output of 3000-3300kWh/yr.

I have an electric car but not a model that Octopus accepts, so I instead of 7 off peak hours, I get 4.

As Dolor mentions, Octopus will accept pretty much any plug-in vehicle for Go or Go Faster (Go Faster has options of 4 or 5 hours off-peak). You do need a compatible vehicle for Intelligent.

If you want a 7-hour off-peak period, there's always Economy 7 - but the tariff is much more expensive than Go or Go Faster.

I am purchasing a 10kw battery to charge with excess from the solar and charge off peak.

For 6 to 8 months of the year, you are likely to have some excess solar. Depending on your overnight consumption (and how good the weather was) this may be enough to get you through the night.

My solar array is probably a bit smaller than yours but my worst day in June saw 3.3kWh generated.

My worst day last December was 0.07kWh.

I see no point selling my excess for 3p/kWh and the being charged 28p/kWh at night.

FYI Octopus's SEG rate is 4.1p/kWh.

My current bills are £37 per month but I have underfloor heating in a very insulated house. I'm hoping that with the battery, I'll always be running on 7.5p/kWh maximum.

It would be quite unusual for 10kWh/day to be enough to keep your house warm during winter, but id by "very insulated" you mean Passivhaus or similar I guess it might be possible. How much did you use last winter (which was milder than average)? And the winter before (more typical)?