DIY... am I crazy?

[markocosic]

That's a load of money.

 

 

Tesla packs are 55 kWh and ~£5.5k (£100/kWh) but add £££ for the BMS and good luck with running into a 48V lead acid inverter

https://www.ebay.co.uk/itm/354146011363

(stick one in the basket and wait for the seller offer)

 

MG ZS are 2.4 kWh at either 12.8 or 25.6 volts (model specific) and a more idiot proof chemistry (LFP) than Tesla so easy to run into a 48V lead acid inverter and ~£400 (a little under £200/kWh)

https://www.ebay.co.uk/itm/275376281563

 

 

IMO automotive gear is likely to be higher quality items than no-name Lithiums. More cost effective too.

 

 

For @sanch3z I'd spend the money on as large a PV array as you can now; DIY installed; and worry about batteries at a later date. Don't touch SolarEdge with a 40' barge pole unless you are completely up to speed on the consequences of being locked into their ecosystem though.

 

[PhilT]

14 hours ago, markocosic said:

Don't touch SolarEdge with a 40' barge pole unless you are completely up to speed on the consequences of being locked into their ecosystem though.

 

might be worth the risk if, as they claim, they will be a pioneer in rolling out V2x technology - what's your view on what those consequences are?

[markocosic]

Consequences?

 

You've got a load of electronic gar up on a roof that's unlikely to outlast the panels, and needs scaffolding and the panels removing to repair it, and only works with their inverters and their inverters only work with their batteries and their charges etc. Bend over the fence and take it up the backside on pricing and support.

 

The minimum that an EV will draw when charging is ~ 1.4 kW. SolarEdge can't do any smart diversion here because it's controlled by the vehicle not the charger. The charger is a dumb socket that sets the available power draw.

 

V2G will similarly depend on the vehicle rather than the PV inverter. SolarEdge don't make vehicles. They're selling you a vendor locked PV system rather today on the promise of doing something that they can't do tomorrow.

 

Fit regular panels, regular (Tigo) optimisers if actually required for shading, and allow yourself to install A N Other inverter / battery / V2X setup in the future as and when this becomes available. Committing to installing a Solaredge inverter to go with the Solaeedge battery and the Solaredge charger to go with the Solaredge car feels like something that you should be paid to do rather than paying to do!

[Nickfromwales]

23 hours ago, Marvin said:

Hi @Nickfromwales

Are you intending to use the EVE LifePO4 grade A or Grade B ones?

 

I've seen grade A suggest down to -5C

I believe the ones that run down to the sub zero temps have an integral electric blanket  to keep the cells from getting that cold.

Needs more reading tbh, as some descriptions are void of comprehensive details.

The batteries own BMS probably takes the first chunk of charge to warm the cells, before allow the cells to recharge.

Just picked up most of these scraps of info by scouring the net and some off-griddy forums.

Plenty of gold out there, and here, just got to stop digging at some stage and plug this lot in. 

[Dillsue]

16 hours ago, markocosic said:

Consequences?

 

You've got a load of electronic gar up on a roof that's unlikely to outlast the panels, and needs scaffolding and the panels removing to repair it, and only works with their inverters and their inverters only work with their batteries and their charges etc. Bend over the fence and take it up the backside on pricing and support.

 

Fit regular panels, regular (Tigo) optimisers if actually required for shading, and allow yourself to install A N Other inverter / battery / V2X setup in the future as and when this becomes available. Committing to installing a Solaredge inverter to go with the Solaeedge battery and the Solaredge charger to go with the Solaredge car feels like something that you should be paid to do rather than paying to do!

Putting Tigo optimisers or any individual module electronics on the roof gives just the same problem as SE optimisers if you get a failure.

 

SE optimisers need to be connected to an SE inverter to get the safe 1 volt output feature to work, but SE produce a tool that allows the safe 1 volt feature to be disabled and I beleive their optimisers can then work with any inverter. Youll loose the monitoring but the optimisation will still work.

 

As with everything in life if you want something that performs better then theres a price to pay which is the case with SE, but thats far from being had over a barrel. If you want the individual module monitoring and a better performing system then youve initially got to put your hand deeper in your pocket than you would with a simpler system, but thats an individual choice rather than a blanket "dont touch them"

[sanch3z]

On 03/09/2022 at 08:39, JohnMo said:

Because 5.12kW is bigger than 16A, so was G99 scheme, not G98.

isn't it based on the size of the inverter rather than the PV capacity? So as long as the inv falls below the tolerance (3.6kw (I think)) a G98 is sufficient. This does raise another question though...

If your PV array is 5.6kw, why throttle it to a 3.6kw inv, as surely the most you will be able pull/use is 3.6kw? I know PV will never all run at maximum capacity, but that's only using around 65% of the PV capacity. Is the theory you're covering yourself for more cloudy days? If you're running a decent sized battery it seems silly to waste stuff on these days???

[sanch3z]

On 03/09/2022 at 14:02, Nickfromwales said:

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. 

 

Interesting. I think the reason that kit is pitched at 'off-grid' (not that I want that), is because it's mostly aimed at people with Caravans, or small workshops. LiFePO4 is certainly an interesting topic, and one that needs more discussion as the cost of most systems are doubled when batteries are added. With regards to their cons, it would see not operating in cold conditions is the only one. I've seen posts on YouTube that recommend seating the inverter below the battery stack as the heat is passed up through keeps them warm. Personally speaking my entire set-up if possible, will go in my garage that's part of the house, so it never experiences super low temps.

[sanch3z]

On 03/09/2022 at 15:58, Nickfromwales said:

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.

shame there's nobody out there stripping and testing these batts, seeing if the thermal cut-off etc. is there and works correctly...

[sanch3z]

On 03/09/2022 at 16:19, joth said:

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)?

 

extra compatible controllers like eddi will need adding to the system to maximise it's potential. Personally speaking i'm leaning towards the Hyundai panels as they have a better spec and higher capacity for the relative space. But the eco-worthy solution made my question whether the other system my pal is getting for £17k is good value. He's no dummy so has done his own reading and research but when I see two systems at apparent ends of the scale i'm forced to ask "is there a suitable solution in the middle, can I get a 5.6kw system with a 10kw battery around the £12k mark?"

[JohnMo]

21 minutes ago, sanch3z said:

isn't it based on the size of the inverter rather than the PV capacity? So as long as the inv falls below the tolerance (3.6kw (I think)) a G98 is sufficient. This does raise another question though...

If your PV array is 5.6kw, why throttle it to a 3.6kw inv, as surely the most you will be able pull/use is 3.6kw? I know PV will never all run at maximum capacity, but that's only using around 65% of the PV capacity. Is the theory you're covering yourself for more cloudy days? If you're running a decent sized battery it seems silly to waste stuff on these days???

But 3.6 kW inverter will have a small tolerance for over locking possibly a few 100W not a couple of kW.  Then if you want 5.6kW you get into an a correctly sized inverter, but with export throttling. Or you go G99.

[sanch3z]

On 03/09/2022 at 20:24, markocosic said:

That's a load of money.

 

 

Tesla packs are 55 kWh and ~£5.5k (£100/kWh) but add £££ for the BMS and good luck with running into a 48V lead acid inverter

https://www.ebay.co.uk/itm/354146011363

(stick one in the basket and wait for the seller offer)

 

MG ZS are 2.4 kWh at either 12.8 or 25.6 volts (model specific) and a more idiot proof chemistry (LFP) than Tesla so easy to run into a 48V lead acid inverter and ~£400 (a little under £200/kWh)

https://www.ebay.co.uk/itm/275376281563

 

 

IMO automotive gear is likely to be higher quality items than no-name Lithiums. More cost effective too.

 

 

For @sanch3z I'd spend the money on as large a PV array as you can now; DIY installed; and worry about batteries at a later date. Don't touch SolarEdge with a 40' barge pole unless you are completely up to speed on the consequences of being locked into their ecosystem though.

 

Interesting strategy looking at used automotive batteries, it sounds shrewd but i'm not sure i'm brave, or knowledgeable enough to go down that route!

With regards to the size of my PV array. I feel it makes sense to max what my roof will take. Whilst the scaffolding etc. up I might as well add what I can. I still want a 8-10kw battery for the nights and winter days though, and I would rather do stuff in one hit so I can make sure it's working well together before any trades leave.

Very interesting point about SolarEdge... I know very little about them, expect their batteries in the EU currently don't offer islanding however they are hoping to add this certification early next year.

[sanch3z]

20 hours ago, markocosic said:

Consequences?

 

You've got a load of electronic gar up on a roof that's unlikely to outlast the panels, and needs scaffolding and the panels removing to repair it, and only works with their inverters and their inverters only work with their batteries and their charges etc. Bend over the fence and take it up the backside on pricing and support.

 

The minimum that an EV will draw when charging is ~ 1.4 kW. SolarEdge can't do any smart diversion here because it's controlled by the vehicle not the charger. The charger is a dumb socket that sets the available power draw.

 

V2G will similarly depend on the vehicle rather than the PV inverter. SolarEdge don't make vehicles. They're selling you a vendor locked PV system rather today on the promise of doing something that they can't do tomorrow.

 

Fit regular panels, regular (Tigo) optimisers if actually required for shading, and allow yourself to install A N Other inverter / battery / V2X setup in the future as and when this becomes available. Committing to installing a Solaredge inverter to go with the Solaeedge battery and the Solaredge charger to go with the Solaredge car feels like something that you should be paid to do rather than paying to do!

ok, you've touched on a very important point for me – serviceability. I'm keen to include either optimisers, or inverters on each panel to cover the shady issue, but my problem with this is servicing when one eventually has an issue. Is there a way to add these somewhere, that's more accessible, or are they always going to be situated on the rear of the panel? If they are then how do you limit exposure to issues?

[sanch3z]

28 minutes ago, JohnMo said:

But 3.6 kW inverter will have a small tolerance for over locking possibly a few 100W not a couple of kW.  Then if you want 5.6kW you get into an a correctly sized inverter, but with export throttling. Or you go G99.

yes, it would seem like you are doing a 5.6kw system a disservice throttling it to a 3.6kw inv. It's probably worth paying the money, and going G99. I have read that some energy companies refuse to let you connect to them unless you get an MCS install ticket, and lots of these ppl/compaines will only certify a system they provide. Over a Barrell here!!!

[JohnMo]

If your panels are on the roof, could you bring the optimisers/inverter inside the roof, then it's just a loft ladder to get at them

[sanch3z]

20 hours ago, markocosic said:

Consequences?

 

You've got a load of electronic gar up on a roof that's unlikely to outlast the panels, and needs scaffolding and the panels removing to repair it, and only works with their inverters and their inverters only work with their batteries and their charges etc. Bend over the fence and take it up the backside on pricing and support.

 

The minimum that an EV will draw when charging is ~ 1.4 kW. SolarEdge can't do any smart diversion here because it's controlled by the vehicle not the charger. The charger is a dumb socket that sets the available power draw.

 

V2G will similarly depend on the vehicle rather than the PV inverter. SolarEdge don't make vehicles. They're selling you a vendor locked PV system rather today on the promise of doing something that they can't do tomorrow.

 

Fit regular panels, regular (Tigo) optimisers if actually required for shading, and allow yourself to install A N Other inverter / battery / V2X setup in the future as and when this becomes available. Committing to installing a Solaredge inverter to go with the Solaeedge battery and the Solaredge charger to go with the Solaredge car feels like something that you should be paid to do rather than paying to do!

Had a quick read of tigo optimisers, they sound flexible but they have a single point of failure. They act as a tunnel for current to flow, so if one goes they all go. Back to needing scaffolding etc. to fix the issue. Why don't people make these things more accessible???

[SteamyTea]

59 minutes ago, sanch3z said:

If your PV array is 5.6kw, why throttle it to a 3.6kw inv, as surely the most you will be able pull/use is 3.6kw

Half the time they produce nothing, then half of the remains time they produce less that 100W, half again, between 100W, but below 200W.

So while it is true to say you get less maximum power, you probably get a lot more energy oversizing. If you store that energy, you can design to draw more power via other methods.

[JohnMo]

2 minutes ago, sanch3z said:

yes, it would seem like you are doing a 5.6kw system a disservice throttling it to a 3.6kw inv. It's probably worth paying the money, and going G99. I have read that some energy companies refuse to let you connect to them unless you get an MCS install ticket, and lots of these ppl/compaines will only certify a system they provide. Over a Barrell here!!!

Not heard that one.

 

The other way to look at throttling is

 

A lot of the year you will not get 5.6kW out of your system, even on a good day you will only get 5.6kW for an hour or so.  Your 3.6kW should be output for most of the year depending on angle and direction 

[sanch3z]

10 minutes ago, JohnMo said:

If your panels are on the roof, could you bring the optimisers/inverter inside the roof, then it's just a loft ladder to get at them

well, this is part of a proposed extension that includes a loft extension. Which is the reason i'm looking at DIY as i'll have the trades and scaffolding up. There is the possibility of creating a small cupboard/access panel to house something like this. I didn't know if anyone has done this sort of thing before. Basically increase the length of the optimiser cables and move them inside. That way unless a panel breaks, everything is reachable...

Saying all this, what's wrong with an old fashioned ladder? A mate does bird proofing of PV systems and it's done via ladders. Just need to turn everything off, nip up, swap an optimiser and away you go?

[SteamyTea]

2 minutes ago, sanch3z said:

Saying all this, what's wrong with an old fashioned ladder? A mate does bird proofing of PV systems and it's done via ladders. Just need to turn everything off, nip up, swap an optimiser and away you go?

Have you fitted a module. Easy enough to fit as you can brace against the rail.

Once fitted the rail is covered.

[sanch3z]

7 minutes ago, SteamyTea said:

Have you fitted a module. Easy enough to fit as you can brace against the rail.

Once fitted the rail is covered.

no but i'm not sure scaffolding is necessary. I'll likley get my mate up there... owes me a few favours and is better with heights.

 

[SteamyTea]

1 minute ago, sanch3z said:

no but i'm not sure scaffolding is necessary. I'll likley get my mate up there... owes me a few favours and is better with heights.

 

Get a couple of spare modules as well.

[JohnMo]

And as they scrape that man from the pavement, his mate kept hold of the panel, but is stuck on the roof and can't get down as he has no hand free.

 

[SteamyTea]

36 minutes ago, JohnMo said:

And as they scrape that man from the pavement, his mate kept hold of the panel, but is stuck on the roof and can't get down as he has no hand free.

 

The 18 kg panel, plus wind loading.

Does this mate have a spiderman suit?

[sanch3z]

8 minutes ago, SteamyTea said:

The 18 kg panel, plus wind loading.

Does this mate have a spiderman suit?

yes, yes he does.

but get the point...

[PhilT]

23 hours ago, markocosic said:

only works with their inverters and their inverters only work with their batteries and their charges etc. Committing to installing a Solaredge inverter to go with the Solaeedge battery and the Solaredge charger to go with the Solaredge car feels like something that you should be paid to do rather than paying to do!

regarding compatibility of SE optimisers with other inverters, they say:-

"Benefits of the SolarEdge P370i universal optimizer
Stand-alone optimization technology (IndOP™) - allows operation with any inverter and does not require any additional interface hardware"