Solar Battery - Yes/No?

markin

Has anyone got that calculater posted to show a good return, I get 25 years on old rated and 14 years at current rates that likely won't last, Even if i knock off 2k for saving £200 by charging at night i get 15 years.

The only real benefit seems to be peace of mind if you get a lot of power cuts.

https://great-home.co.uk/solar-export-guarantee-seg-calculator/

Alnat1

My system cost £8600 so I put £5500 panels, £3100 for 4.8 battery. Generation 4200kWh a year, our use 2900. Agile tariffs in/out. Calc says 7.5 years

Slinky

markin said:

Has anyone got that calculater posted to show a good return, I get 25 years on old rated and 14 years at current rates that likely won't last, Even if i knock off 2k for saving £200 by charging at night i get 15 years.

The only real benefit seems to be peace of mind if you get a lot of power cuts.

https://great-home.co.uk/solar-export-guarantee-seg-calculator/

The chap who came and quoted for us said you'll lose power in a power cut anyway even with battery storage,unless you have an EPS, which he showed us, and was just a double socket with 13amp capability.

EricMears

Slinky said:

markin said:

Has anyone got that calculater posted to show a good return, I get 25 years on old rated and 14 years at current rates that likely won't last, Even if i knock off 2k for saving £200 by charging at night i get 15 years.

The only real benefit seems to be peace of mind if you get a lot of power cuts.

https://great-home.co.uk/solar-export-guarantee-seg-calculator/

The chap who came and quoted for us said you'll lose power in a power cut anyway even with battery storage,unless you have an EPS, which he showed us, and was just a double socket with 13amp capability.

You might need to ask him about 'islanding' which would disconnect your system from the mains then allow it to keep functioning.

Screwdriva

markin said:

Has anyone got that calculater posted to show a good return, I get 25 years on old rated and 14 years at current rates that likely won't last, Even if i knock off 2k for saving £200 by charging at night i get 15 years.

The only real benefit seems to be peace of mind if you get a lot of power cuts.

https://great-home.co.uk/solar-export-guarantee-seg-calculator/

Exactly - There is little to no financial benefit for a battery for a modest consumption household and hasn't been for a year now. Add the limited battery life (often < half the life of PV) and added complexity and you begin to wonder what could possible feel so good about it?

If you heat or commute using electricity, the need for 10+ kWh of storage becomes pronounced due to the need for cheaper tariffs/ next to no generation during the winter months. 

Only the Tesla powerwall has a true household power cut protection (vs. dedicate circuits that are protected by other batteries like the Libbi).  Better than nothing but not quite as imperceptible as we are often led to believe. 

Waywardmike

Screwdriva said:

Exactly - There is little to no financial benefit for a battery for a modest consumption household and hasn't been for a year now. Add the limited battery life (often < half the life of PV) and added complexity and you begin to wonder what could possible feel so good about it?

Hate to be one of 'those' people, but unless you have a battery it's difficult to explain the feeling around having one.  

Will I get the money back from my battery purchase?  probably, but maybe not.  Does it make my system infinitely more 'useable'... without a doubt!  I don't care if it's sunny spells anymore, I'll just put the washing machine or dishwasher or any other high use appliance on knowing that if a cloud inevitably rolls over as it tends to in this country the battery will cover the shortfall and I'll pull nothing from the grid.  

I liken it to all the Tesla owners at work. I listen to them complain about them all the time, build quality, software issues, Tesla only servicing etc...  but in the next breath they'll tell you it's the best car they've ever owned.  I don't understand the rationale, but I'm not a Tesla owner...

Petriix

I do think that people sometimes forget about the "money saving" bit after "green & ethical" on this board. Of course most of us with solar would love to have batteries, but they really only make financial sense for a minority, especially with current inflated prices. 

propnut

I have recently had a 6KW PV system installed and went with a 7.2KW (actual useable is around 6) battery. I just felt I might as well future proof as energy prices are unlikely to come down anytime soon. Now I must say I had a self build off-grid system before this which is still running in parallel. That has another +-4KW lead acid storage so I have plenty of energy. In fact I now top up my off grid with the on grid using a Marlec iBoost Diverter so that when my main battery is full and starts sending to the grid firstly my MyEnergi Eddi rediverts this to my hot water tank and when that is full the CT of the iBoost detects surplus and sends it to my Lead Acids via a fairly beefy battery charger.

As Waywardmike says it makes for a worry free "useable" system. All our appliances run flat out during the day and there is still enough energy at the end for the wife to do the cooking. We are an all electric home except for the heating and even then we have electric heaters in the main living areas. 

I use my off grid batteries on a 5KW inverter to run the lawnmower, charge my eBike, use my power tools, run a small fridge in my garage and any other stuff as needs dictate. Will I get my money back, well according to the calculator posted above, apparently in 15 years. That's ok, I have no intention of moving.

propnut

Oh and just to add here is an example of my grid electricity costs over the last few days. You can see the sunny vs the cloudy days.

Screwdriva

Petriix said:

I do think that people sometimes forget about the "money saving" bit after "green & ethical" on this board. Of course most of us with solar would love to have batteries, but they really only make financial sense for a minority, especially with current inflated prices. 

Well said. There is also the ethical argument about the carbon intensity involved in the way all that lithium is dug up, then preventing it from going into an EV, where far more carbon can eventually be offset and then denying the local grid access to the green electricity generated by PV to offset neighborhood consumption.

All for little to no financial gain and a "feeling"!