The Solar Thread

Yes, Life4PO and they do use power to manage heat so are a little less efficient, but we’re talking maybe 50W per battery, per hour in the cold months. So on tickover at night in the winter the inverter and the batteries will draw around 250-300W but in the rest of the year that will be 150-200W.   They charge and discharge at full rates even in the cold periods.

Interesting re the guidance change.  Our inverter is in the loft on an end wall, the Tesla power wall and gateway are both outside – one of the main advantages of the Tesla unit I think is its temperature management.

Re insurance companies, I rang mine (M&S) and told them and they weren’t remotely bothered.  Asked them to log the notification however

So on tickover at night in the winter the inverter and the batteries will draw around 250-300W

So around 2kW each night?  Never knew that!

I’m sure I’ve asked before, but is there a third party solar and battery monitoring software/app I can use with my Huawei set up. The Huawei one is temperamental to be polite and constantly loses communication. Is there anything out there that is not tied to a specific manufacturer’s equipment?

Yes – Home Assistant.

As per @daffy I run it on a Raspberry Pi

yeah we are not using 2kw a night in heating  – glad of that sure.

one of the main advantages of the Tesla unit I think is its temperature management.

Up till very recently – powerwalls were NMC and temperature management was essential to prevent runaway.

Couldnt pay me to put NMC inside my house and my installer was correctly adamant on that as well.

lot less woried about LiFe4Po

So around 2kW each night?

On average across a year – yes. 2-4kW per day to run the system.  Most of that is PV yield, but at night, you have to power the inverter from something and then if it’s cold the batteries will keep circulating.  If you don’t have a battery, it all just goes dormant until there’s enough sun the next morning.

Many people using the FoxESS system need to insulate their batteries over the winter. Fox used to say that it was a terrible idea but then released an insulated enclosure that combines the inverter and batteries together.

I have Foxess batteries in my garage which I insulate with a bog standard water tank kit. Sits around 25 degrees, creeps up a few degrees during forced charge.

A question for the hive mind. I have 3.4kWp pv and a 6.9kWh battery. When away from home, the Growatt app shows grid import as zero, as you would expect, yet my smart meter records around one kWh per day consumption. Any idea why the discrepancy?

The inverter responds quickly but not instantly to changes in both generation and demand.  Those tiny changes can add up over a day.

Thanks, I’ll have a look.

So then. with the advice that we shouldnt have batteries in lofts (mine is in the garage loft which naturally has a lot of highly flammable garage stuff in it) Should i be looking at building a fireproof box for them?

The problem isn’t so much the risk of the batteries catching fire (arguably above you might be better than below you in that case anyway), but the fact that there’s several hundred kilos of metal perched in the loft. The risk is to emergency services who enter the building after you’ve escaped, because I would quite expect a stack of batteries falling through a weakened loft ceiling to go straight through the floor below as well.

My stack of batteries were under the stairs (which is the only escape route) and ultimately I bit the bullet and paid to have them moved to the garage, but in a neat and tidy all-in-one unit. Roughly the same capability as a Powerwall, but also integrates the solar PV. Existing batteries slot into the base.

You’ve got an interlinked smoke alarm up there, I assume?

I can understand why a heap of stacked batteries sat on the floor such as the fox or similar presents a risk sure.

Giv energy and pure drive amongst others should have their metal casing’s vertically mounted to the building structure.

but as alan l alluded to in another thread it sounds like the documentation was released with the SMEs having been consulted but refusing to comment on the proposals so they have gone defcon 5 with the most stringent of rules

The problem isn’t so much the risk of the batteries catching fire (arguably above you might be better than below you in that case anyway), but the fact that there’s several hundred kilos of metal perched in the loft.

I’d also say that most ceilings, regardless of being weakened by fire or not, are not built to have a several hundred KG of weight concentrated in a small footprint – be careful where they’re located!

A big dude in a loft will have a similar if not worse concentration of mass.  My heaviest (13kWh – LiFePO4) battery is 98kg.  It’s footprint is substantially greater than a footprint.

I still wouldn’t pile them on the floor – but it wasn’t so long ago water tanks would be routinely sited up there.

Would I do it in a modern house. Would I buggery. Most of them can barely hold their own weight

#costengineered

A big dude in a loft will have a similar if not worse concentration of mass.

Still doesn’t make it OK!
(And the bloke isn’t up there 24/7)

As per TR, I’ve seen some ceiling joists in older houses that couldn’t even cope with the ceiling being overboarded!

The risk is to emergency services who enter the building after you’ve escaped, because I would quite expect a stack of batteries falling through a weakened loft ceiling to go straight through the floor below as well.

If the fire is that well developed that there is a risk of structural collapse, there shouldn’t be anyone committed into building, they’ll just be soaking the ruins from outside.

If the fire is that well developed that there is a risk of structural collapse

“My dad/brother/daughter/son/cat is still in the building.”

“My dad/brother/daughter/son/cat is still in the building.”

So you saved yourself with helping others……..Nice

My DRA…..if the building is that structurally comprised that there is internal colapse in progress there is no way I would have sent others in to save an un saveable life.

Been there got that T shirt

So you saved yourself with helping others……..Nice

**** me, this place is unpleasant now.

hey you started it with your hypothetical scenario making it up as you went along

Yay I can finally join in.

Had 7kW of panels on an even East/West split fitted on the roof with a 5kW  battery installed in the garage.

Overall happy with it so far although the electrical install in the garage isn’t the neatest but will tidy that up myself.

Have moved over to Octopus Flux am I then better to move onto the Intelligent Flux?

Also will it be worthwhile to fit an iBoost (or similar) to control the immersion heater?

Also will it be worthwhile to fit an iBoost (or similar) to control the immersion heater?

We got one free with our installation. I like it and it works fine but not sure if I would have bought one. What we dont use we feed back in so whether the numbers add up is not clear.

Also will it be worthwhile to fit an iBoost (or similar) to control the immersion heater?

That question used to be a no-brainer as you can think of an immersion tank as a liquid battery – but now there’s real actual batteries it’s much cloudier!

Others are better qualified to answer but I presume you can charge your battery and then use spare power to heat the water?  I’m interested to hear what the priorities are.

I don’t have a battery so for me it’s simple – and I’m on Agile so my [load shifted] evening usage is not actually that expensive.

(I’m also on the original FIT rate so I get a bonkers amount of money for half of my generation regardless of whether I export it or not – so I may as well use it)

i wanted to get an iboost or similar installed and the installers told me not to bother as its cheaper to use gas and sell your export

These days it depends on a combination of your tariff for I/O, your battery storage and discharge capability and when you would use the water.

Octopus Flux Import in the early morning is around the same as export during the day, so if you shower in the morning, you could heat overnight and simply export the rest once your batteries are charged.  Showering in the evening would probably mean it’s best to use your export to charge the water tank during the day.

Agile pricing is…complicated, but essentially equates to the same thing as flex, but with more money involved I/O per kWh.  I think if I was running an ASHP or a Electric water cylinder, I’d be on Agile, charge in the early morning and export as we shower in the morning and there’s more often than not cheap power in the early morning.  Not sure I’d bother with an iBoost unless I had a MASSIVE (>8.5kWp) solar array.

Speaking of batteries… The control module on our (new) 10kWh Huawei developed a fault about two weeks ago and decided it would failsafe to off. Slightly annoying as there have been at least some sunny days since it failed and exporting is not as good for us as storing.

That said, a good sunny day has seen our usage from the 7kW string of panels average out at about 20% less than before (even including the car charging).

I could really do with rotating the workshop roof about 30 degrees to the south, but I think that might be a little too much to do…

Others are better qualified to answer but I presume you can charge your battery and then use spare power to heat the water? I’m interested to hear what the priorities are.

Heating water takes a huge amount of electricity, so unless you have a massive array you’re barely going to notice. As mentioned above, gas is so cheap you’re betting off heating water using that and then selling a few spare kWh of leccy in peak hours.

So we have a 8kwh mixed east/south/west array capped at 6kwh, with Tesla powerwall and solar iboost. Basically the iboost will only kick in once the battery is full and all house demand is sorted. We have a 300L hot water tank and on sunny days it does completely heat it. I’ve seen it take between 8 and 15/16kwh’s to do this.

We are on oil, so I’d prefer to use less oil, it may be slightly fiscally better to use oil to heat the hot water and sell electric at 15p but that’s not the direction I’ve gone in. Thumbs up for the iboost from us. It’s easy enough to turn it off also and they’re not expensive.

Heating water takes a huge amount of electricity, so unless you have a massive array you’re barely going to notice. As mentioned above, gas is so cheap you’re betting off heating water using that and then selling a few spare kWh of leccy in peak hours.

My 250L tank took about 10.5kWh of power yesterday and probs put the water up from about 30c to around 60c – it saved me burning oil.

Our place by the beach is 100% electric (no gas around) and from April to at least the end of Sept the 3kWp array does all the hot water pretty happily – so you do notice it even with a smaller array.

I use overnight electricity to heat the hot water tank on the Octopus Intelligent tariff. Because I get 30p/kWh for anything I export thanks to a wonky meter, it’s much more cost-efficient to export than use the generated power myself, and it means that the oil boiler doesn’t run and the water is heated by green(ish) oof-peak power.

But since you can get 15p/kWh to export with anyone I can’t see why you’d want to invest close to £k in a solar diverter.

A £k? An iboost is £300!

Oops. It’s been a while since I looked at them.

😂 if they were a grand I’d be right with you tbh!

I decided it was a better use of my roof space to put solar thermal panels on.

I could have fitted a single ,400watt panel where my thermal panels fit.

250l tank.

Does the following indicative quote look ‘fairly average’ to those that have had installs or quotes themselves? It’s from Octopus Energy. 4 bedroom 80s house, link semi detached, reasonable insulation (cavities & loft), no EV. Location is North East England. Roof is NE-SW pitched on both sides. (if that helps 🤷🏼‍♂️). TIA

Solar Panels: 12 panels (1.7m x 1.1m)
Micro-Inverters: 12 Enphase micro-inverters (1 micro-inverter per panel)
Battery: 1 Enphase 5kWh battery
Total Price: £9,829
Inclusions: Scaffolding, installation, and all electrical systems required for operation.