Notifications

Clear all

Battery storage to run Heat Pump.

Broadsman · 2025-03-11T09:29:44Z

I am about to have a Powerwall 3 fitted to help with the cost of running my heat pump. ( Ignore the capital cost of the battery!). I have no solar and intend to charge at the cheap Cosy rates and discharge during the standard rate times. However, I saw a Youtube video yesterday which suggested that Octopus might be about to introduce a special Heat Pump tariff so that they can be run at the Cosy cheap rates 24/7.. If this turns out to be true, would there be any point in having the battery, apart from occasional Backup?

Page 5 / 5 Prev

Energy Storage

Last Post by AgentGeorge 2 hours ago

53 Posts

13 Users

23 Reactions

4,573 Views

RSS

Scalextrix

(@scalextrix)

Reputable Member Member

Joined: 1 year ago

Posts: 112

13/10/2025 4:12 pm

@transparent Eleven Energy have a full Sodium-ion system with inverter, no recommendations

👍

ReplyQuote

Majordennisbloodnok

(@majordennisbloodnok)

Famed Member Moderator

Joined: 4 years ago

Posts: 1151

13/10/2025 4:24 pm

Posted by: @scalextrix

↑

...

I'm hopeful that the newer Sodium Ion chemistry launched by BYD for their small affordable domestic car market may soon find it's way into stationery battery storage.

...

16 sodium atoms walked into a bar, followed closely by a masked man in a cape.

...

Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Na Batman!

Sorry; couldn't resist. Taxi's already on its way.

105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs

"Semper in excretia; sumus solum profundum variat"

🤦‍♀️

ReplyQuote

Toodles

(@toodles)

Illustrious Member Contributor

Joined: 3 years ago

Posts: 2292

13/10/2025 4:48 pm

@majordennisbloodnok I’m not sure you will be able to receive treatment on the NHS!

Toodles, heats his home with cold draughts and cooks food with magnets.

ReplyQuote

Batpred

(@batpred)

Reputable Member Member

Joined: 11 months ago

Posts: 228

14/10/2025 8:43 am

Posted by: @transparent

↑

The concepts behind running inverter, BMS and battery combinations are just as important as the 'rules'.
You gradually get a feel for the subject matter.

That gut-feel is crucial in the learning curve to making decisions which are 'safe'.

Hats off to the ones that persist, @Transparent ! 😀

Not saying never again, tempting to think learnt enough and the next battery DIY assembly would be quick..😉

But those pleasant moments packing the cells into the box will not be easily decoupled from the weeks leading up to it... 😃

16 kWh Seplos Fogstar battery; 8kW Solis S6-EH1P8K-L-PLUS hybrid inverter; 1 x Ohme Home Pro EV charger; HA lab on mini PC

👍

ReplyQuote

AgentGeorge

(@agentgeorge)

Estimable Member Member

Joined: 10 months ago

Posts: 93

25/11/2025 4:42 am

@jamespa I have 5kW PV and 5kW battery. By using the 8pus cheap rate and PV to charge the battery, for the months April thru October I averaged 98% on the cheap tariff, the battery was supporting the house after PV declined avoiding paying higher rates standard hours.

Now the temps have dropped below 8C, the HP is working harder and the battery is not big enough to support the house load.

I calculated adding a second 5kW battery would support the HP at 1.6kW max load Nov-Mch. The payback for this extra battery would be twice that of the first battery as it only pays back Nov-Mch, approximately 18 years assuming static electricity charges, 14 years if you assume 2.5% increase per year.

If I can get a second hand battery at half the cost of new and avoid fitting charges by installing it myself, I could justify a second battery.

ReplyQuote

Page 5 / 5 Prev