Running a house off grid, what you need and how it works
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- Опубликовано: 7 апр 2023
- Using a 7.5kW Solax solar inverter and battery storage to run my house off grid in EPS mode.
I made a few mistakes along the way with this one but will be back with modifications and adjustments soon. I will also have some island mode testing coming up soon once everything is complete.
Along with some real world tests trying to run off grid!
One thing I didnt include in the video is the inline rcbo feeding back into the change over switch during EPS mode. Its in there I just forgot to film it in all the excitement of everything else!
This also involved a brand new dual stack Proteus consumer unit which has RCBOs that are bi directional and can be back fed! Awesome products and I will be including the contactor soon (if it works as my plan says it should lol).
The Shelly is an awesome product, used the shells for years but this is a nice upgrade to have during the CU move.
Next step is the panels and as its my roof I can take my time and show some of the hook mounting and tile removals in more detail.
Soon we will have rid of the gas boiler and I am thinking of including an electric heat only electric boiler alongside a tank arrangement!
Thanks for watching!
Great project and really good walk through will give you a great demo to potential customers of what you can install for them
Thanks Richard and this is what a lot of the content is all about.
This is a really interesting project Mark. Really enjoying it. Don't forget to put a interlinked smoke alarm in that cupboard and also it would be really good to have a light in there with battery backup to allow you to see what is going on if there is a power cut. I am looking forward to see the next part of the project as it develops.
Already has a nest multi smoke in there for the boiler mate.
Thats what the spare wire is for EM microwave round bulkhead.
I'm enjoying myself! You can tell the bit I less enjoy cos I've put it off till the end 🤣🤣🤣 roof work!
Thanks mate
Mark
@@electrician247 Hope you get a nice day or 2 for the roof work. No rain or strong wind. Remember it needs to be
Sunny but not too sunny
Warm but not too warm
Should make for another interesting video.
Interesting video, you could also spilt the incoming grid tails and add a small cu with the hybrid inverter on that. Then when the change over switch is thrown to eps that cu will be dead. That’s how I have gone about it on installs with multiple inverters
Yes Matt, I mentioned that in reply to another comment. I considered it but I think the contactor is easier. If it doesn't work that's my plan B. Good shout.
Hey Mark, great video, learnt a lot. I have pretty much the same system and want to add in the EPS part now to power the main board when the GRID is out. Ideally automatically. If we put an ATS in then we will of course get the loop between EPS and GRID mode as the Inverter is powered off the main board as well. Did you get the contactor method working you mentioned in the video or did you go with putting the inverter on another subboard thats not EPS powered? I'm not a sparky just interested so please do treat me like an idiot as thats the level I'm at :-)
Great video, for that size inverter did you have to do a G99 application?
Yep, sure did mate. Thanks.
Hi, random comment on this video but what determines if you need supplementary bonding? Are you always supposed to actually test between a tap and metallic light for example ?
I’d also like some help on how isolating transformer (shaver socket) works. The earth is removed right? But you don’t get a shock if you touch live cable, even though you are stood on ground. However, if you touch normal socket live cable you would get a shock? Even if you removed the earth . Confused how you wouldn’t get a shock of shaver socket when you’re stood on earth 0v touching 230v. Could you do a video possibly or give explanation on these topics
Many thanks
Very interesting video thanks Do you have a link for the Shelly product? Had a quick look on their website and couldn't find it thanks
It looks like it's the Shelly Pro 4PM.
@@yngndrw. Thanks Andrew
amzn.to/3KMwM5y
Very interesting to see an EPS setup, you don't tend to see too many of them. I like the changes you've made over your last install as well, I think it looks a lot better having the DC isolators off to the side.
Do you really need a separate contactor for the inverter supply? Can you not just use the spare contacts within the change-over switch? Obviously there's no spares for a three phase install but it should simplify your install. I do wonder how you'd do the separate contactor though as surely it would need to be on the incoming grid supply which has no protection (Aside from a switch-fuse) - I'm guessing you'd also need a second grid-only board just for that?
You mentioned three phase when discussing the meter cabinet, are you upgrading to three phase as well or was that a mistake? If so I'm surprised that the DNO are happy with the much space for a three phase supply but it's good to know if they are.
Lol meter cabinet was supposed to say smart meter not 3 phase if that's what I said 🤣.
The EPS does go into the change over switch. The problem is it also re supplies the inverter mcb and thus the cycle begins.
Can be solved either by a little CU pre the change over switch just for the inverter grid feed but that removes user control to a point so I didn't like that.
I will demo the contactor on the next video but in essence when grid supply is removed lost it would open and break the feed into the inverter.
You are correct it would be wired from the change over switch but we have a set of terminals in there that link direct to the grid input terminals so no issue doubling up. As the sub main is on an 80A fuse we have an element of OCPD so just need to size the cables and contactor accordingly.
In my mind it maps out fine but we shall see when I put it together and share it soon!
Thanks!
@@electrician247 I thought it was a mistake but I get excited when people talk about domestic three phase so I had to ask!
What I mean about using the change-over switch in place of the contactor, I mean using an extra set of terminals for the interter's grid supply (E.g. L3) - So you'd have terminal 13 going to the inverter RCBO and and terminal 14/16 going to the inverter grid connection. I'm not sure if it's allowed (Or wise) to mix pre-post MCB domains like that within the change-over switch but logically I think it would do what you need.
Regarding the contactor's supply and the sub-main OCPD, you're going to end up with the coil of the contactor being fed from an 80A fuse so I think you're still going to need a little consumer unit before the change-over switch regardless.
I may well be missing something as it's hard to follow without a diagram, but I think that's correct. If I am missing something, I'm sure all will be clear in the next video which I look forward to as always.
@Andrew Young yes I have gone around the houses with a few ideas. What I am trying to do is have the automatic disconnection when the grid goes down to inverter beeps away lol. But on the grid power returning I don't want the inverter to automatically see that. Reason is very often round here we get a few false starts with the grid energy returning lol. So I am trying to keep an element of manual control.
It's a fun one but one of the reasons I got a roomy CU to have a good play around and learn a few things on my own system lol. Will be sure to share the failures and successes in my experiments lol and gratefully receive tips from those watching such as yourself! Thank you.
@@electrician247 Ohhh I see, yes latching off does make sense now that you mention it - You'll essentially end up with a DOL starter by the sounds of it. I appreciate you taking the time to explain and document your experiments for us all to learn from.
Hi Mark, Q: how did you install the proteus switch fuse without breaking the main fuse seal to isolate the supply to the property?
Thanks
I am blessed that my meter has an isolating switch in it . It's a shame they stopped doing that. I've shown it in previous videos.
😊😊
Hi Mark was this your first installation I too call it Solax not Sola X, how did the stately home go are you going to be doing a ground mount
Yes it was the 1st mate. We all start somewhere! That job is still waiting to proceed. It will in the end. Planning issues...
Hi. Did you have a switched mains earth so that the system is just connected to he earth rod when in EPS mode? Can you say why?
Yes and yes
Thanks. Very helpful. 👍
Hi Mark good video.
Did read to keep the TNCS esrthing and add a rod or mat so the rod on backup mode the rod is supplementary.
See mcs battery storage guidance version 2.
Yes, as I understand it, the earth shouldn’t be switched but the grid earth cannot be relied upon, hence adding the rod
@@newlinerealboi3434 yes it doesnt technically make it a TT earrhing arrangement but more adding a rod makes it supplemented to the TNCS system. This was/is an complex issue and on the 18th edition and 2 course had a good chat with the tutor on this issue... he said he connected with the IET and the guy that wrote most of the battery mcs regs kygon I think he was called on that issue ans he never replied despite there being abit of a issue on this exact issue.
My own thinking is adding a rod does not make it TT but it's just supplemented TNCS and should be called that.
There wa going to be a revision and that was adding a earthing arrangement to new builds for TNCS incase of loss of PEN conductor...it got taken out on this 18th edition amendment 2 at the last minute so I see this coming in in future regs.
Issue becomes if you have alot of houses on your new fangled Supplementary TNCS with rod how big do you make this earth conductor? He said 25mm but that's massive lol but has a point as you dont know the current that has to carry if there was a PEN fault..
And other issue is were is the DNO or someone else put there earthing point/rod as you could get a fault introduced into your own rod...
Earthing and TT are great but there are some design issues to consider always.
All food for debate and thought ans I am most certainly not try to be clever just looking for views.
Most systems I've done have been fully off grid and TT earthing arrangements or just a type A rcd metal clad socket as a full backup system of house ESS opens a bit of can of worms.
How are you able to power the complete board in eps mode, if solax limit the eps load at roughly 9amps?, cheers
As discussed by careful limitations on what is used. However power is available and everywhere and at slightly more than 9amps try 32A… I wouldn’t expect to continue as normal with all house loads. But can choose in this setup.
All that said I now have a GivEnergy AIO which will output in combo with the PV generation. So even better!
@@electrician247 thanks for the reply 👍 I’m stuck utilising the eps on my solax system as I’m 3 phase, only have options for powering a single phase via a auto transfer switch, whilst 3 phases switches do exist, the eps just wouldn’t handle to demand, what with all new builds all 3 phase now, hoping new products come to market, I’ve got 4 solax batteries, and have regular power cuts, and currently sat in darkness, need to get the power out
@@adamwalker-holden5432 what rating is your 3 phase inverter? It should supply most circuits but you would have to load limit your consumption. Even with 4 batteries it won’t last long on high demand. Plus it would spike the EPS and shutdown. But would give you at least sockets for small power, lighting and potentially heating depending on rating of heat source
Doesn't the solax inverter already have surge protection on Dc ?
The hybrids do, strong ones don’t. However we always fit into the fixed wiring rather than rely on a product in the equipment perhaps built to a product standard separate to requirements. Same for RCD protection and DC isolation as well.
Think they’ll struggle to get a smart meter in the cabinet now with that switch fuse unit
Not so. Has one in it right now with ease. It's my house. None issue
@@electrician247 ah good stuff. I know some meter technicians can be struggle to fit meters!
should a 40a max be on a 50a breaker for some headroom? 40 x 1.2 = 48a (or 50a) breaker?
On the inverter? Limited to 25A on the AC output so no. The max PV input is beyond that but it’s sorted locally via the DC coupled battery and clipping if required. This is why sizing of the inverter, array and required AC output is hard work sometimes.
@electrician247 yep the inverter sorry. The manual listed 40a max input ac current which I'd have thought wood mean a 50a mcb for the inverter ac input
I've ordered the x1 matebox advanced to increase the load to 60a which is helpful, allowing the inverter to supply the house main board, although >80a would have been a nice option. Maybe in a future solax product
@@muso31 that’s the peak when grid and solar charging is taking place. Doesn’t hurt to move to a 50A. The inverter will peak beyond its max rating for short durations but isn’t consuming all that power from the AC side. 40A would be fine but nothing wrong with upsizing if you are concerned.
@@muso31 the mate box gives some very good flexibility however I’ve since swapped to a GiveEnergy AIO and gateway. That is an absolute game changer.
Remember your max power on the solax system is still governed off grid by what the inverter can produce. That doesn’t change with a mate box. It just allows for an element of automatic change over.
See here midsummerwholesale.co.uk/pdfs/ff8080818465bc79018473eea49e002c.pdf
how much does the installation cost?
Impossible to say. To many variables on each install
I want to take my house off grid. I already have solar panels with batteries. How can I find anyone to do this for me?
You will most likely need extra hardware and it is very difficult to go fully off grid all of the time. For occasional backup it’s pretty easy. If you want to email the equipment you currently have I can take a look for you if you want. Mark@powersonic.co and it is just .co on the end
Solax with lead acid DIY battery?
Where we need connect NTC battry sensor?