Battery or no Battery - Please help me decide!

Screwdriva

powerful_Rogue said:

Economy 7 also offers a cheap rate for overnight charging, especially EDF at the moment. Bulb also offer an EV tariff where you don't need to have an EV to qualify.

Bulb are not accepting new customers I believe?

powerful_Rogue

Screwdriva said:

powerful_Rogue said:

Economy 7 also offers a cheap rate for overnight charging, especially EDF at the moment. Bulb also offer an EV tariff where you don't need to have an EV to qualify.

Bulb are not accepting new customers I believe?

I've seen on a few solar facebook groups that Bulb are still accepting customers whilst awaiting the sign off by ofgem.

pcgtron

powerful_Rogue said:

Niv said:

Solarchaser said:

At 3100kwh annually, id say go with solar and diverter.
Worth noting though, if you normally heat your water with gas, you may find its cheaper to continue doing that and export your excess.

Thanks @Solarchaser my heating is oil so I think it is worth using a diverter at current prices, if the price drops then I would recalculate. 

I think I have settled on no battery (still open to being swayed by compelling reasons). Feels that the payback side of it doesn't stack up (using the calculator, battery and 5.5p SEG = 12.4 years) and I could put the money in a savings account to get ~£250/yr currently. I think my biggest lingering thought was getting it now vs never due to the 20% tax of getting it later.

Very foggy where I am today. So far only produced 1kWh via solar PV. It's a nice feeling knowing the house is being run via the battery that I charged up last night for 12p per kWh, rather then paying 34p per kWh today had I not had it.

Batteries are like marmite, some love them, some hate them. I was on the fence, however so glad I went for them, especially with that 20% VAT saving. Who knows what the electric will rise to come April, keeping in mind, without the government intervention, we would be on around 60p+ per kWh.

Powered my whole house all day for 7.5 pence per Kwh today due to having battery storage. Very satisfying when no solar generated 

Niv

pcgtron said:

powerful_Rogue said:

Niv said:

Solarchaser said:

At 3100kwh annually, id say go with solar and diverter.
Worth noting though, if you normally heat your water with gas, you may find its cheaper to continue doing that and export your excess.

Thanks @Solarchaser my heating is oil so I think it is worth using a diverter at current prices, if the price drops then I would recalculate. 

I think I have settled on no battery (still open to being swayed by compelling reasons). Feels that the payback side of it doesn't stack up (using the calculator, battery and 5.5p SEG = 12.4 years) and I could put the money in a savings account to get ~£250/yr currently. I think my biggest lingering thought was getting it now vs never due to the 20% tax of getting it later.

Very foggy where I am today. So far only produced 1kWh via solar PV. It's a nice feeling knowing the house is being run via the battery that I charged up last night for 12p per kWh, rather then paying 34p per kWh today had I not had it.

Batteries are like marmite, some love them, some hate them. I was on the fence, however so glad I went for them, especially with that 20% VAT saving. Who knows what the electric will rise to come April, keeping in mind, without the government intervention, we would be on around 60p+ per kWh.

Powered my whole house all day for 7.5 pence per Kwh today due to having battery storage. Very satisfying when no solar generated 

This absolutely appeals to me however even at those rates I don't think I would see a return in investment. I fully accept that a battery will not suddenly stop working once it gets outside its warranty period (unless made by apple) , but for ROI calculations calculating returns over 10 years seems sensible. I would need to save ~£500 per year to pay for the battery and even by using 7.5p electricity (mixed with free from the array (which would have to be costed at the SEG rate anyway), I just don't think it would be viable in my situation. 

I think its great it works for some and also that the convenience it brings outweighs ROI  but I am struggling to justify it for me. 

Its a real heart vs head thing for me, my heart says go for it but my head says it wont pay for itself over 10 years and that money could be earning ~5% risk free right now. 

ispookie666

My biggest concern with batteries is the longevity of companies - will they be around to honour their warranties, if need be?  My own experience with GE has made me wary.  You would end up with 100% loss if the company goes bust and your battery packs up.  

Anyone checked how Lead Acid batteries stack up for ROI?  

RealtimeBlues

powerful_Rogue said:

Screwdriva said:

powerful_Rogue said:

Economy 7 also offers a cheap rate for overnight charging, especially EDF at the moment. Bulb also offer an EV tariff where you don't need to have an EV to qualify.

Bulb are not accepting new customers I believe?

I've seen on a few solar facebook groups that Bulb are still accepting customers whilst awaiting the sign off by ofgem.

Bulb are in Administration and are taken over by Octopus

powerful_Rogue

RealtimeBlues said:

powerful_Rogue said:

Screwdriva said:

powerful_Rogue said:

Economy 7 also offers a cheap rate for overnight charging, especially EDF at the moment. Bulb also offer an EV tariff where you don't need to have an EV to qualify.

Bulb are not accepting new customers I believe?

I've seen on a few solar facebook groups that Bulb are still accepting customers whilst awaiting the sign off by ofgem.

Bulb are in Administration and are taken over by Octopus

It's not your usual type of administration. They are still taking on customers if you phone and ask.

Screwdriva

Niv said:

This absolutely appeals to me however even at those rates I don't think I would see a return in investment. I fully accept that a battery will not suddenly stop working once it gets outside its warranty period (unless made by apple) , but for ROI calculations calculating returns over 10 years seems sensible. I would need to save ~£500 per year to pay for the battery and even by using 7.5p electricity (mixed with free from the array (which would have to be costed at the SEG rate anyway), I just don't think it would be viable in my situation. 

I think its great it works for some and also that the convenience it brings outweighs ROI  but I am struggling to justify it for me. 

Its a real heart vs head thing for me, my heart says go for it but my head says it wont pay for itself over 10 years and that money could be earning ~5% risk free right now. 

If the numbers don't stack up, wise move! 

Magnitio

Deleted_User said:

Here's a conclusion that I'm coming to as a result of another discussion.

In a system without a battery backup the inverter (which has a running cost of it's own) presumably switches on when the sun shines and switches off when it doesn't. When the sun is shining all generated electricity is converted from DC to AC by the inverter as it's produced. You use what you need and the rest is diverted to the grid. 

Specified inverter efficiency figures will be based upon this EFFICIENT usage. 

HOWEVER when you add a battery into the system I see potential for huge inefficiencies. Essentially (I believe - and other may correct me on this) it introduces the same efficiency problems that you have when you use a solar generator. 

In order to run appliances, the inverter needs to run to convert the DC stored in the battery into AC. That means you could be running the inverter 24/7 and that can use up a big percentage of solar energy generated in the depths of winter. Now, there MAY be some smarts in the system that get around this problem - so that's something to find out.

But essentially, if my suspicions are right - you could be in a worse position than me (with my generator). I can CHOOSE to only run a few things off my generator and switch the power hungry inverter off the rest of the time. But with an installed system with battery I'd be wanting to find out more about the implications. So for example, if your fridge is on 24 hours but you're out at work all day and nothing is running then or at night, then it could be costing you more energy than your solar is producing just to keep the inverter running.

So **IF** the above suspicions are correct (and its just me applying logic - not based on knowledge of how they work) an option to consider might be a system tied to the grid without battery, and a separate stand alone generator (optionally fed by solar) to use for emergency back up in a more manageable/controlable way.

You are correct that there are overheads in running a hybrid inverter that is on 24/7, though it would have to be a particularly bad day or a small PV system for the inverter consumption to exceed the PV output. For a lot of people with PV and battery, they are on a variable rate tarrif and top up the battery when the costs are lowest. The setup I have allows for scheduling of how the system is used, for example:

• 00:00 to 03:00 - use mains electricity as load is low and so are prices
  
• 03:00 to 04:30 - charge battery to 50% at cheapest overnight rate
  
• 04:30 to 06:00 - use mains electricity as load is low and so are prices
• 06:00 to 00:00 - battery is used as load has increased and so have prices. Depending on the weather and load, battery will be topped-up from PV
  

The Octopus agile rates vary considerably from day-to-day which affects how much value you get from charging the battery. On rare occassions the price is negative (you get paid for what you consume). It is often less than 10p/kWh overnight, but in the last week it has been higher.

If I were to go to the extremes of trying to get the most out of each kWh purchased or generated, then more could be saved by manually turning off the inverter between 00:00 and 03:00 and 04:30 and 06:00, but I can't see many doing that!