Jump to content

DIY... am I crazy?

sanch3z

By sanch3z
in Photovoltaics (PV)

 Share

Recommended Posts

sanch3z Member

sanch3z

Posted
Posted

So a friend of mine has convinced me to included a PV system as part of an extension we're planning – makes total sense and a solid argument. He is using a reputable local company to deliver his, but as we will have scaffolding up and trades, in i'm thinking about a semi DIY install... Is this a crazy idea?

 

His 5.6kw solution is £17k, which is a massive investment (and perhaps too much for me) but he's not compromising, and just wants someone to take care of it all:
 

  • 15 x Hyundai 395 panels
  • Solar edge inverter (SE6000HAPP)
  • Solar edge modbus meter
  • Solar edge 10kw battery pack

 

Our needs would be similar to his, except I would like the following:

 

  • Islanding
  • diverter (hot water)
  • overnight battery charging from the grid in the winter months
  • Perhaps add and EV in the future

 

Funnily enough, my brother who is in IT, is looking at a similar system but totally DIY, suggesting an Eco-worthy system as he currently uses a small one on his caravan to good effect. I initially bulked, thinking it was a bit 'Heath Robinson' but certain elements are maybe quite clever, and cost-effective? Mainly the LiFePO4 Lithium Battery array, as eight of these would provide 9.6kw of back-up for £3.5k

 

So my questions:

  • Is doing a semi-diy install a bad idea?
  • Am I seeing both ends of the scale here, is there a happy medium?
  • Am I better to spec my products and get a reputable company to supply and fit?
  • Are the LiFePO4 batteries a good idea (seem popular abroad)?
  • Can I add automatic islanding to this battery array?

 

Appreciate any insights, new to this but keen to understand more rather than just pay money and put my feet up.

 

Link to comment
Share on other sites
  • Replies 57
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

Radian
Radian

No, after. They say up to one month after so fairly relaxed.

Conor
Conor

DIY is no problem. That's a big chunk of money. My DIY 4.5pkW cost £4800 (no batteries). That was £4200 for the panels, cables, optimisers, inverter (solaredge), GSE in roof tray kit and £800 for the

joe90
joe90

Is it?, including batteries!. I know very little about batteries, how does that compare to say a power wall?

Conor Advanced Member

Conor

Posted
Posted

DIY is no problem. That's a big chunk of money. My DIY 4.5pkW cost £4800 (no batteries). That was £4200 for the panels, cables, optimisers, inverter (solaredge), GSE in roof tray kit and £800 for the sparks to connect the two string cables to the inverter and consumer unit and commission. I installed the trays and panels myself, connected the panels to the optimisers and main string cables. It's literally fool proof plugging together.

  • Like 1
Link to comment
Share on other sites
JohnMo Advanced Member

JohnMo

Posted
Posted

I also did my own also, did the trays, pre ran all the cables in conduit, mounted isolation switches, inverter, electoral guy did the rest and signed the G98 form.

 

Mine is 3.1kW, just over £2.5k for everything.  Electrical costs lost in the new house wiring costs.

 

I think only the battery can go into island mode, PV cannot, not sure how legitimate be artery islanding is within G98/99 rules.  Not sure of the maths of batteries yet.  I self consume everything the PV gives me, via a diverter to heat hot water.  Battery no use to me.

 

  • Like 1
Link to comment
Share on other sites
sanch3z Member

sanch3z

Posted
  • Author
Posted
30 minutes ago, Conor said:

DIY is no problem. That's a big chunk of money. My DIY 4.5pkW cost £4800 (no batteries). That was £4200 for the panels, cables, optimisers, inverter (solaredge), GSE in roof tray kit and £800 for the sparks to connect the two string cables to the inverter and consumer unit and commission. I installed the trays and panels myself, connected the panels to the optimisers and main string cables. It's literally fool proof plugging together.

yeah it's a balance, did you complete your 'g' form prior to installation, and can you feed back to the grid and charge your batteries, or is it just a PV system? £5k is where I would expect a DIY 5kw system to be without batteries...

Link to comment
Share on other sites
Conor Advanced Member

Conor

Posted
Posted
1 minute ago, sanch3z said:

yeah it's a balance, did you complete your 'g' form prior to installation, and can you feed back to the grid and charge your batteries, or is it just a PV system? £5k is where I would expect a DIY 5kw system to be without batteries...

Still not done the g98 form... It's on the list. It's just PV for now, will consider batteries in the future, but highly unlikely as we're going to be buying an EV in the next year which will take all the excess PV and be charged off peak, so don't see the value of a second battery.

Link to comment
Share on other sites
sanch3z Member

sanch3z

Posted
  • Author
Posted
7 minutes ago, Conor said:

Still not done the g98 form... It's on the list. It's just PV for now, will consider batteries in the future, but highly unlikely as we're going to be buying an EV in the next year which will take all the excess PV and be charged off peak, so don't see the value of a second battery.

yes I understand, the battery is mainly to utilise any surplus and back fill overnight on a cheaper tariff. I'm probably wrong but thought the g98 needed to be done before the initial install?

Link to comment
Share on other sites
JohnMo Advanced Member

JohnMo

Posted
Posted
46 minutes ago, sanch3z said:

yes I understand, the battery is mainly to utilise any surplus and back fill overnight on a cheaper tariff. I'm probably wrong but thought the g98 needed to be done before the initial install?

G98 is after the event, not before, permission is pre granted up to 16A per phase.  G99 is prior to install, as you are seeking permission as the array is bigger than 16A

Link to comment
Share on other sites
Dillsue Regular Member

Dillsue

Posted
Posted
1 hour ago, sanch3z said:

yes I understand, the battery is mainly to utilise any surplus and back fill overnight on a cheaper tariff. I'm probably wrong but thought the g98 needed to be done before the initial 

Its unlikely a 6kw inverter will be manufacturer limited to 16 amps so youll need to submit a G99 application and get approval before connection to the grid.  

  • Like 1
Link to comment
Share on other sites
Marvin Advanced Member

Marvin

Posted
Posted (edited)
13 hours ago, Radian said:

No, after. They say up to one month after so fairly relaxed.

Hmm. I had to apply to install a 5.12kW system before commencing and SSE (our DNO) had to check that the existing local network would take the supply. 

 

4 5kW more than 16amp??? so G99????

Edited by Marvin
Link to comment
Share on other sites
Marvin Advanced Member

Marvin

Posted
Posted (edited)
1 hour ago, Conor said:

Our max system output is 4.5kW, but the 5kW inverter has been limited to 3.7kW by the commissioner, so G98. 

Again I was advised by our DNO that they did there calculations by using the maximum the inverter would allow to the grid, and not the amount of panels or what the limiter had been set to, hence we are allowed a 6.0kW inverter.

 

Edited by Marvin
Link to comment
Share on other sites
Nickfromwales Advanced Member

Nickfromwales

Posted
Posted (edited)
19 hours ago, joe90 said:

@Nickfromwales, your thoughts please! Less than £7k including batteries sounds good to me (but what do I know 🤔). What other kit would be needed to grid tie this?

A bit more M2 of roof space for the same wattage of other 'on-grid' panels, but 6 and two 3's if you have the space to fit them?

It says completely off-grid, so you'd need to research the inverter to see if it will accept a generator ( or grid AC ) feed as well as the panels and batteries. If not, it wouldn't be suitable for retrospective integration into an existing on-grid setup like yours afaik.

The Iconica 11,000W hybrid I'm trying to source atm is one such device, eg which is capable of fitting into either camp ( on / off grid ), but, as I am not familiar with that offering linked above, I cannot say yay or nay for you.

Would not be cost effective if you cannot simply plug the lot straight into your CU. The Iconica gives UPS out of the box also, with near zero switchover time, so in a power cut you'll stay lit and burning with just a 'blink'. You get a complete system, high capacity / spec, for the price most are just buying the batteries at ( size for size ). I have my 24 panels, all Tigo'd ), just the inverter to source and then it's "f**k you grid!". 

I do like the price / stats of the LiFePO4 batteries, and am looking on Alibaba etc to see what's about atm. Batteries are the one thing I'm currently deciding, with choices - panels ( procured ), optimisers ( procured ), and inverter ( waiting on new stock to arrive ) - now cemented. 

 

LiFePO4_pros_and_cons.png?v=1641413389

Edited by Nickfromwales
Link to comment
Share on other sites
Nickfromwales Advanced Member

Nickfromwales

Posted
Posted

https://www.ebay.co.uk/sch/i.html?_ssn=debattery-66&store_name=kepbattery&_dmd=2&_oac=1&_trksid=p2047675.m3561.l2562#item2416985d05

 

Cheaper than Eco-worthy? Free shipping, so seems a better option. £365 ( total in Ebay checkout all in ) vs £482 ( including 'estimated taxes' at EW checkout ) at a quick glance. Both have internal BMS.

 

Those 24v / 100Ah batteries come in @£748 per, so circa £1500 for 4.8kWh / £3k for 9.6kWh, so, if they are looked after and last 8 or more years I'm sure I will stay in the black. I'd be happy to break even tbh, if it means not buying from the grid. If your inverter is already your BMS ( hybrid ) then I like those prices! Buyer says "best offer" too, so may try a cheeky lower bid and see what they will drop by.

 

Considering qty 2 of the 24v offerings for the get-go ( installed in series to get me to 48v for the Iconica ) and then possibly add more when I increase the size of the array, but tbh I will probably up my direct ( self ) consumption instead of adding more batteries as that's got longer legs / better economics. I very likely won't do anything more after the initial install eg until I have 4 seasons of statistical data tbh to reflect on. The plan is to oversize the PV regardless, to then have enough residual for the winter to chew into space heating costs, as I am going to fit A2A to get AC in the summer ( defo happening ). That can be used to heat the home too, or at least do a lot of the constant background heating vs heavy lifting ( where the existing gas CH will kick in to give things a nudge when it gets baltic ) plus a view to using gas at night ( if so required ) for quiet operation when sleeping.

 

Over-all's will improve slightly with some downstream fabric upgrades, and the gas system will go ( be evicted ) eventually I expect, but I'm working on a decade long proposal atm as I will probably build something new / efficient after that and just migrate the panels with me ( 25 year warrantied - 30+ year expected lifespan on those ). Buyers perspectives will be much different by then I expect, so we will see if I leave the kit behind or not.

Link to comment
Share on other sites
joth Advanced Member

joth

Posted
Posted

Does the eco-worthy have G98 certification for grid tie? Can't see it mentioned on the website (only skimmed briefly) and the title of "off grid" system raised a flag.

Seems a good deal if it does. 

Things to check:

Can the batteries charge from AC?

Can you schedule the mode (e.g. to charge from cheap rate over night in winter)?

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing
×
×
  • Create New...