What's comes first EV connector or PV + batteries

[Bob Smith]

Hello Gurus,

The more I read on this forum the more I think my project to expand my existing 4kWp is not ambitious enough (To summarize, I was thinking to put 3 panels on the roof of my garage facing south (3 is the max), 2 on a low flat roof facing south west (2 being the maximum) and 4 on a gable facing west. As I want to keep my FiT from my existing 4kWp system, I will need a new inverter. I will also add batteries which will be charged by the excess of the two arrays (old and new).

However, as said this community inspires me and I think I am not ambitious enough. For a start, it is difficult to get an installer so the bigger the project the more they will be interested. More importantly, though, I start to realize that you can actually benefit from your solar electricity to charge your EV car.

I still have roof space available as you can see from the photo. It is facing North (a bit to the east) but at 18h30 today this is what it gets


16 panels could fit on the top roof and 3 on the small one. This will mean an additional 16 + 3 + 9 = 28 Panels + the 16 I already got. (I know I will need to move to 3-phase get DNO, etc...) and this will definitively cost well over 10k if not 20k.

In addition, we currently do not own an EV but will surely do within the next 5 years.


Therefore my question:
Should I go first with the PV installation and ensure compatibility with a future EV charger or should I prioritize the EV car and its charge and later go ahead with my PV extensions?
Obviously, I cannot go ahead with both at the same time (unless you crowdfund me )

What are your thoughts and what else should I consider?
Thank you all in anticipation.

 

[Barx]

Anything further north of straight East to West, I personally wouldn't bother. Others may have different views, but for me even straight east or west is a push.

It looks good now, but autumn through winter to spring, it isn't going to look so pretty.

 

[Bob Smith]

Hi Barx, I agree the best time for those panels will be from May til July (we are already 1 month past the soltice). However, if they can produce anything between 500 and 1000kWh per year. To be it is worth it this will also better distribute the generation throughout the day.


As for East and West I must respectfully totally disagree. I personally know two families with this set up.
One has a 4kWp installed at the same time as me from the same provider in Jan 2016 (same panels, same inverter, same installer). As expected they generate about 15 to 20% less than me but they start generating sooner and keep generating later in the day. They generate between 3 and 3.3MWh/year
The second family has had their panels installed in April (their panels have 20% efficiency while mine from 2016 only 15%), and they so far generated more than me since April. (OK maybe my panels need a clean but still).

In addition, if you intend to export it is beneficial to produce early and late to balance out the total generation on the grid. In Germany over 10 years go, they started to promote such installation because installation facing South started early 2000 and they realized they had far too much electricity at mid-day.

Of course, if you have the choice between South and East-West and could do only one installation you should go with South.

What are your reasons to say that East and West is a push?

 

[Barx]

You have to consider the payback period. how much will it cost you to get the panels up there and operating?
If you generate 1000kWh for the year AND self consume 100% of it, that is only a saving of about £270 (based on todays figures). Yes I know energy prices are likely to go up, but still...

So, if we say it costs 5k for the install of the panels. And you save 270 quid a year, that over 18 years before you break even. In that time, you can pretty but guarantee that the inverter will need replacing at least once, so that pushes the payback out further.

p.s. I know these are crude numbers but they won't be a million miles out. And these are really best outcome, as you won't self consume 100% without storage, which will cost another tidy packet.

Again, this is just my opinion. I used to install a lot of PV so had to do a lot of the calcs. For me, I could neevr make battery storage viable in most cases.

 

[Bob Smith]

Hi Barx

I appreciate your feedback and the discussion. At the moment the project is in the scoping phase. I am already planning to have panels on the gable, the flat roof (behind the small roof you see in the photo and the other side of the small roof) that will include batteries that will be charged by the new panels and my existing panels. Therefore increasing the charging potential. I thought if they come for the 9 panels and the batteries, why not come to also install the panels on the roof marked by a red cross.


Anyway, the topic of the thread is about EV charger and having a PV system that would help to charge the EV. Is there any logic to have one first installed rather than the other one?

 

[Badger]

I have installed enphase inverters and 14 panels on a South facing of 2 panels 380w each the east west side is 12 panels 3 of 380w panels and 10 of 320w panels and through the day they generate and start generating at present about 6am and finish about 9pm winter we don't know what they will produce but our best day so far in July being the best month we were generating 24kwh and only needed to use of that half of it that was generated

 

[Badger]

Some snapshots of East west for shed roof and upper roof and south on front

 

[binky]

Again, this is just my opinion. I used to install a lot of PV so had to do a lot of the calcs. For me, I could neevr make battery storage viable in most cases.

For many years I told my customers not to fit batteries, the early ones cost more than they could possibly save them. However, that was 5/6 years ago, and batteries have improved an awful lot and got cheaper. I would say payback is now around 6 years, maybe 10 at most.

 

[Bob Smith]

It seems no one has an opinion on what should be installed first? (see topic of the thread)

 

[King Arthur]

What's the point of prioritising an EV charging system now when by your own admission you probably won't have an EV for about five years?

Five years is a long time in this game - technology changes, EVs are still developing and who knows what might happen to energy prices?

I don't think there's a definitive answer because payback periods are inevitable measured in years and no one knows what will happen during those years that might shorten or lengthen the payback period. So basically, it's a betting game and the golden rule is not to bet more than you can afford to lose, ie don't RELY on achieving payback. My impression, from those I know with solar PV systems, is that they've gone that route for many reasons but saving money in the long term is not one of them. They just 'like the idea', they feel they are helping to save the planet, they are interested in the technology, etc, etc. I don;t know anyone who said they spent many thousands of pounds today so they could save a bit of money on their energy bills in 5, 10, 15 years time.

They get their 'value for money' from owning the PV system itself. It's a bit like cars. We could all choose to drive a cheaper car but we're happy to spend a bit more for the enjoyment of having a 'better' car in its own right. Money is for spending and getting some form of enjoyment from that spending. A 'feel good' factor if you like. Some people 'enjoy' and expensive holiday, an expensive car, a bigger house, or in this case a PV system. Fine, nothing wrong in that at all - if you have the cash to spare. But if you want to save money or grow money then there are many far better ways to invest for growth than spending it on a PV system . . . . as anyone with a decent pension scheme will attest.

It's frustrating because PV seems instinctively the right way to go, which makes it an easy decision for the heart, but when the numbers are scrutinised it's not quite so obvious for the head. So perhaps just ignoring the numbers is the way to go because no one can be sure how they will change over the next 5, 10 15 years anyway.

 

[Barx]

It seems no one has an opinion on what should be installed first? (see topic of the thread)

If you are really keen on getting the additional panels fitted I would get them done first, for multiple reasons.

• It would be more expensive to get someone to re-visit to fit the additional panels rather than fit all panels whist there.
• you don't currently own an EV, so why put a point in for it now?
• EV charger tech is changing fast at the moment and isn't really mature enough to be future proof. So, if you install charger now, in say 3 or 4 years when you get your car, the charger unit (and maybe even the cable run, etc) could be obsolete to an extent. So you could find yourself with an expensive socket sat on the wall for a few years only to have to change it when you eventually get the EV.

 

[binky]

It's frustrating because PV seems instinctively the right way to go, which makes it an easy decision for the heart, but when the numbers are scrutinised it's not quite so obvious for the head. So perhaps just ignoring the numbers is the way to go because no one can be sure how they will change over the next 5, 10 15 years anyway.

Many of my customers fitted PV because they were frustrated by low interest rates on their savings. Ok the money is on the roof permanently, but Roi used to run at about 8%, not sure what it is at the moment as I havn't calculated that for a while. It's also fair to say many customers also wanted to leave the planet in a better condition for their grandchildren, and some just hate paying bills to energy companies.

 

[Murdoch]

OP have you got the historic readings for the last couple of years ?

ive been pondering about adding batteries to our system but there are so many months of the year when the generation seems to low

 

[Bob Smith]

Thank you all for your contribution.

Sometimes I post things to generate a debate, share ideas/views to benefit the community and of course myself, One never knows what idea someone can come up with that may lead to another one and so on.

I was wondering if some batteries and inverter were more suited to be used in conjunction with a EV charger (I don't know, maybe rate of discharge, max power etc... I am aware that at home there is no need to charge a light speed unlike when you are on the motorway. If you charge what you need in 1h or 4 hours during the night, it does not matter while you sleep)

Regarding, charging the batteries in winter. When I first considered batteries, I thought I would over size them (kind of having 100kWh or more) that would charge over summer to then be used in Winter. I then realized it would be super expensive and also that batteries are not designed to store energy for months like this. I then learnt the best option is to charge batteries at night when it is cheaper when they had not been charged enough the previous day.

Regarding ROI , I will start another thread dedicated to ROI, as I find this topic very interesting and I am also surprised so many people only think of PV system with a ROI in view.