Cheapest home storage battery options?

arty688

I think the party is over with Octopus , I believe you also need to own an EV to qualify for Go now as well.not that you would pick Go anymore as there are better tariffs out there.

arty688

On your PDF bill it should say when the price ends.

Solarchaser

In theory you always needed to own an EV for the rates.
As they were billed as an EV tarriff.

My price is guaranteed until Feb,  I guess we shall see what the market is like then.

mickyduck55

arty688 said:

On your PDF bill it should say when the price ends.

March 2022.. so that will get me through the winter months...

EVandPV

14th September 2021 here so I'll report back when we get our next bill.
Although our online account still says 14.19p. 🤔
Also, the standing charge seems to have reduced from 25p to 19p so that'll help offset any increase in the daytime rate.

QrizB

Well I've just changed from Flexible to Go, and Octopus seemed to have honoured the prices they offered when I signed up in early September to switch from EDF:

Having this for the next 12 months will be very nice, even on my EAC of 2500kWh/yr!

EVandPV

QrizB said:

Well I've just changed from Flexible to Go, and Octopus seemed to have honoured the prices they offered when I signed up in early September to switch from EDF:

Having this for the next 12 months will be very nice, even on my EAC of 2500kWh/yr!

Can I ask what standing charge they put you on.

QrizB

EVandPV said:

QrizB said:

Well I've just changed from Flexible to Go, and Octopus seemed to have honoured the prices they offered when I signed up in early September to switch from EDF:

Having this for the next 12 months will be very nice, even on my EAC of 2500kWh/yr!

Can I ask what standing charge they put you on.

25p/day standing charge on my Go tariff, slightly more than the 24.1p I was previously on with Flexible.

QrizB

In another thread, the question was asked:

greyteam1959 said:

@QrizB
How much did your battery setup cost ?
If you don't mind me asking.

I've moved my answer to @greyteam1959 over to here, where it is more at home.

That's a good question with several answers.

• The inverter is a second-user Sofar ME30000SP from this guy on eBay. Mine was £450 but I see he's dropped the price a bit.
• My first battery was 16 of these cells (US$320) plus one of these BMS units (US$23).
• Cables and connectors and a 32A dual-pole DC-rated breaker added another £30 or so.

I think that makes about £700 and 1.28kWh, good for playing around with and as proof-of-concept but a bit lacking in capacity. So I'm in the process of adding:

• My second battery is 16 of these cells (US$360) plus one of these BMS units (US$60).

On paper this adds another 3kWh for about £300 but I'm a bit dubious about those cells being the full claimed capacity; I think I'm closer to 2.5kWh. Combined they'll be ~4kWh which *should* see me through the night on solar in the summer and through the day on overnight Go power in the shoulder months.

Winter will be tricky as Mrs QrizB's studio-shed is heated electrically and I've not yet convinced her to let me fit a heat pump. On a cold winter's day she can get through 10-15kWh all by herself.

Man-maths says I've spent £1000 and, based on saving 10p/kWh with Octopus Go (5p/kWh cheap rate vs 15p/kWh peak) I might be saving 40p/day which is a 7-year payback. If I'd been more confident I could've gone straight to the bigger cells and bought 16 of these instead, more capacity for ~£100 less total outlay (once you include BMS costs). Electricity captured from solar PV is worth 15p/kWh and reduces the payback time to a best-case minimum of 4.5 years. The real case will fall somewhere inbetween those two extremes.

I'm pretty sure all my cells are either used or end-of-line and so it will be interesting to see how they last. As a home-built pack it's going to be simple to replace odd ones so long equivalent replacements remain available.

JKenH

QrizB said:

In another thread, the question was asked:

greyteam1959 said:

@QrizB
How much did your battery setup cost ?
If you don't mind me asking.

I've moved my answer to @greyteam1959 over to here, where it is more at home.

That's a good question with several answers.

• The inverter is a second-user Sofar ME30000SP from this guy on eBay. Mine was £450 but I see he's dropped the price a bit.
• My first battery was 16 of these cells (US$320) plus one of these BMS units (US$23).
• Cables and connectors and a 32A dual-pole DC-rated breaker added another £30 or so.

I think that makes about £700 and 1.28kWh, good for playing around with and as proof-of-concept but a bit lacking in capacity. So I'm in the process of adding:

• My second battery is 16 of these cells (US$360) plus one of these BMS units (US$60).

On paper this adds another 3kWh for about £300 but I'm a bit dubious about those cells being the full claimed capacity; I think I'm closer to 2.5kWh. Combined they'll be ~4kWh which *should* see me through the night on solar in the summer and through the day on overnight Go power in the shoulder months.

Winter will be tricky as Mrs QrizB's studio-shed is heated electrically and I've not yet convinced her to let me fit a heat pump. On a cold winter's day she can get through 10-15kWh all by herself.

Man-maths says I've spent £1000 and, based on saving 10p/kWh with Octopus Go (5p/kWh cheap rate vs 15p/kWh peak) I might be saving 40p/day which is a 7-year payback. If I'd been more confident I could've gone straight to the bigger cells and bought 16 of these instead, more capacity for ~£100 less total outlay (once you include BMS costs). Electricity captured from solar PV is worth 15p/kWh and reduces the payback time to a best-case minimum of 4.5 years. The real case will fall somewhere inbetween those two extremes.

I'm pretty sure all my cells are either used or end-of-line and so it will be interesting to see how they last. As a home-built pack it's going to be simple to replace odd ones so long equivalent replacements remain available.

Great example of man maths in action there, thank you. 

I note though you didn’t mention round trip losses which at  (say) 20% would reduce your profit on bought in power from 10p to 7p/KWh and extend your return of capital from 7 to 10 years. People talk of replacing inverters after 10 years and if yours is secondhand that might become 5 years. Will cheap Chinese cells last 10 years or will you be replacing them all in that period?

Do you have 10-15kWh of spare solar available each day in winter for your other scenario, or are you robbing Peter to pay Paul?

Presumably you had £1000 just sitting under the bed doing nothing to fund it all and won’t be losing any income from an alternative investment.

Presumably you have advised your DNO of your new set up.

Of course electricity prices might shoot up and it would pay for itself in half the time. A true man mathematician would have factored that in.

The more man math calculations I see for solar or batteries, the better the Ripple wind farm investment looks.