Battery or no Battery - Please help me decide!

Reed_Richards

[Deleted User] said:

Part of any DNO review will be the ability of the grid to take the export load. Some applicants have been disappointed when a site export limitation has been imposed.

So charging a battery might be a very good thing if you have more solar power than you can use or are allowed to export.

EcoScruples

Screwdriva said:

Petriix said:

Alnat1 said:

Keep reading, and you'll see it's as I said, the only people who say no to batteries are the ones who don't have them 

And that's because the only people who have batteries are the ones who don't bother accurately assessing the ROI, or have very unusual usage. 

Believe me I would have batteries if they made financial sense. I cancelled my Givenergy order (at under £4k for 8.2kWh installed) because the numbers couldn't possibly add up for me.

However, my advice is to do the sums and make an informed decision. 

Well said!  While not every use case is the same (there is no panacea), most households only hurt their financial case by getting a battery. Really heavy evening users, EV + Heat pump households are the only exceptions, as are those as risk of regular blackouts, but even there, the upfront spend on 15+ kWh of storage is hard to digest! 

Let's not forget that batteries, even from the best manufacturers, come with a 10 year warranty and added complexity in the form of external controllers (in some instances). This means that it may very well be that halfway through the life of your PV system, say 15 years or so, your battery and/ or controller may need replacement, starting the ROI clock once again. As someone who has installed off grid solar/ wind hybrid solutions, I would never believe anyone who claims their battery will last the duration of their PV system - it's just well intentioned inexperience talking.  

Rather than listen to any opinion, I always recommend starting with this calculator and working backwards with actual numbers. You won't regret the few minutes it takes to remove all subjectivity from the equation. 

My ROI works out 6 years which leaves 4 years of battery use before needing replacement which makes it a great choice or me.
Glad I invested.

powerful_Rogue

EcoScruples said:

Screwdriva said:

Petriix said:

Alnat1 said:

Keep reading, and you'll see it's as I said, the only people who say no to batteries are the ones who don't have them 

And that's because the only people who have batteries are the ones who don't bother accurately assessing the ROI, or have very unusual usage. 

Believe me I would have batteries if they made financial sense. I cancelled my Givenergy order (at under £4k for 8.2kWh installed) because the numbers couldn't possibly add up for me.

However, my advice is to do the sums and make an informed decision. 

Well said!  While not every use case is the same (there is no panacea), most households only hurt their financial case by getting a battery. Really heavy evening users, EV + Heat pump households are the only exceptions, as are those as risk of regular blackouts, but even there, the upfront spend on 15+ kWh of storage is hard to digest! 

Let's not forget that batteries, even from the best manufacturers, come with a 10 year warranty and added complexity in the form of external controllers (in some instances). This means that it may very well be that halfway through the life of your PV system, say 15 years or so, your battery and/ or controller may need replacement, starting the ROI clock once again. As someone who has installed off grid solar/ wind hybrid solutions, I would never believe anyone who claims their battery will last the duration of their PV system - it's just well intentioned inexperience talking.  

Rather than listen to any opinion, I always recommend starting with this calculator and working backwards with actual numbers. You won't regret the few minutes it takes to remove all subjectivity from the equation. 

My ROI works out 6 years which leaves 4 years of battery use before needing replacement which makes it a great choice or me.
Glad I invested.

4 years +

Battery won't stop working dead on 10 years when the warranty runs out.

EcoScruples

powerful_Rogue said:

EcoScruples said:

Screwdriva said:

Petriix said:

Alnat1 said:

Keep reading, and you'll see it's as I said, the only people who say no to batteries are the ones who don't have them 

And that's because the only people who have batteries are the ones who don't bother accurately assessing the ROI, or have very unusual usage. 

Believe me I would have batteries if they made financial sense. I cancelled my Givenergy order (at under £4k for 8.2kWh installed) because the numbers couldn't possibly add up for me.

However, my advice is to do the sums and make an informed decision. 

Well said!  While not every use case is the same (there is no panacea), most households only hurt their financial case by getting a battery. Really heavy evening users, EV + Heat pump households are the only exceptions, as are those as risk of regular blackouts, but even there, the upfront spend on 15+ kWh of storage is hard to digest! 

Let's not forget that batteries, even from the best manufacturers, come with a 10 year warranty and added complexity in the form of external controllers (in some instances). This means that it may very well be that halfway through the life of your PV system, say 15 years or so, your battery and/ or controller may need replacement, starting the ROI clock once again. As someone who has installed off grid solar/ wind hybrid solutions, I would never believe anyone who claims their battery will last the duration of their PV system - it's just well intentioned inexperience talking.  

Rather than listen to any opinion, I always recommend starting with this calculator and working backwards with actual numbers. You won't regret the few minutes it takes to remove all subjectivity from the equation. 

My ROI works out 6 years which leaves 4 years of battery use before needing replacement which makes it a great choice or me.
Glad I invested.

4 years +

Battery won't stop working dead on 10 years when the warranty runs out.

Very true, I've been told that it'll probably go for maybe 15 years (obviously at reduced capacity) but I've gone for 10 years for ROI purposes.
The good news with modular batteries is I can add another 5kw at the 10y mark and potentially have 11kw still as the battery management system will work the old ones efficiently.
I love having a battery, it feels right and I can play all sorts of tunes when it comes to the ever changing energy market.

QrizB

ispookie666 said:

It's always fascinating when ROI is the first thing people harp about when talking about solar, batteries, ASHP but hardly do the same for white goods, cars etc... 

Two points in response to this:

1. White goods and cars (etc) have non-financial utility. Without a refrigerator you're limited in ways to store fresh foods without them spoiling. without a motor vehicle you're left to the whims of public transport for any journey beyond walking / cycling distance. Solar panels and especially batteries have none of these factors; they exist solely to generate and store electricity, electricity which you would otherwise have to buy from the grid. I very much doubt anyone reading this thread has chosen to install solar panels or a storage battery for aesthetic reasons.
2. ROI does come into the equation with white goods and cars. As one example, there are several people over on the main energy forum who have replaced fully-working-but-elderly fridges and/or freezers due to the high cost of running them. In one case I recall a MSE'r who thought their new fridge would pay for itself within a year. And the same sort of calculation should come into play when choosing a car. My old vehicle was getting about 30mpg, my new one gets 50mpg. The 100 gallons (£800-worth or so) of fuel that I won't have to buy this year was definitely part of the financial equation when I chose the vehicle.
   

Martyn1981

Reed_Richards said:

Dolor said:

Part of any DNO review will be the ability of the grid to take the export load. Some applicants have been disappointed when a site export limitation has been imposed.

So charging a battery might be a very good thing if you have more solar power than you can use or are allowed to export.

Yep, and possibly the solution for me, as the DNO won't let me have any more PV (or battery/V2G export). So a zero export battery application will be required, and I believe that if the unit has a hybrid inverter, then additional PV could be added (via a dedicated PV in), since when the battery is full, the charge controller will shutdown the PV. So an appropriately certified battery will hopefully be acceptable to the DNO, and allow extra PV piggybacking on its controls/certification.

Perhaps an unusual situation, but extra PV, via batteries, may become more important in the future as PV panels get more efficient, and leccy demand (all year) grows, thanks to EV's and heatpumps. So in my case, the batts aren't a standalone add-on, but might open the door to more RE generation too.

Officer_Dibble

I've just run the calculator for my system installed in March - the first time I've re-run it since then. My payback time if I hadn't had the battery would have been 4.7 years at current rates. With battery (which I did get) it's 6 years. At the time of installation the payback times were much closer and obviously both were rather longer, but the recalculation uses Octopus' 15p per kWh SEG rate (which I'm signed up to). If anything it shows how much the calculation can change in a few months.

If the battery can pay for itself within the warrenty period and then declines slowly and gracefully in the few years after that, it'll have been worth it, but there's certainly less of a case for it with decent export rates available.

ispookie666

@QrizB its relatively easy to counter those but would be deviating from the topic of discussion.  
ROI can be important to people but surely is immaterial for me, as I consider Solar and Batteries as home improvements and any savings made on the way is a bonus 

ggmf

EcoScruples said:

Hmm, if your main aim is payback then at the moment everything screams no to a battery.

Disagree, define ROI or 'payback'? As above my ROI on our 'whole' system is 5 years for electricity only, and this will reduce, when further increases in unit prices are applied. This then reduces again to approx. 4 years or less currently if I include savings due to reduction in gas usage and SEG payments are taken into account.

Everybody's utilisation and requirements will be different, need to look at the while installation.

Screwdriva

Officer_Dibble said:

My payback time if I hadn't had the battery would have been 4.7 years at current rates. With battery (which I did get) it's 6 years.

Isn't the point of a battery to reduce that number (vs. increase it)?