Solar panels and battery - any real world recommendations?

I've seen voltage regulators in action (which is what they were called in the plant I worked at).
It was a multi acre manufacturing plant with hundreds of motors around it.

It was the motors they optimised, one by one, which is important. Every one (they started with the largest hungriest ones) was given a regulator and it was slowly dialled down to provide lower voltage whilst watching the current.
Part of what this also did was connect to a control room so if (when) something broke they knew.
This faster response and hence up time funded the project.

It was throwing up decent savings on energy usage, like 10-15% but varied my motor. Some liked the lower voltage more than others, but all saw some energy reduction over time.
I believe part of it (iirc) was due to reduced heat making the motor run more efficiently as it was cooler.
There was talk about it reducing breakdowns but we never included anything from the finance side for that, just a reduction in (demonstrated) energy usage.

I believe (again iirc it was over a decade ago) some stuff like control panels it actually increased the usage if you stopped giving them mains voltage. Many would drop it to 12v anyway so if you fed lower voltage you suffered the same issue as you see in consumer space when a PSU is lower efficiency at 120v than at 240v.

I think the problem in house vs industry is that in a house you will have 1, vs industry where you will have many. It will affect everything downstream so it may improve some things, but will potentially worse efficiency in others (like the PSU I mention above).

FWIW I believe the units were basically the same thing but slightly better so they had more voltage drop choices rather than just three. I don't think they were on like a fully variable dial, but a kind of swappable dial type arrangement.
In fact now I think back they had a more expensive unit that they worked out what voltage to supply a motor with and then a more basic version they would set to that voltage (or close as possible) and then swap them over.
 
Thanks guys.

Ron-ski said:
In the UK, the declared voltage and tolerance for an electricity supply is 230 volts -6%, +10%. This gives an allowed voltage range of 216.2 volts to 253.0 volts

Voltage optimisers don't optimise anything, they are voltage reducers. They are a transformer and just step down the voltage, they usually have three settings, or tap points. So if grid voltage was 240v and you was using the 10% reduction tap, the voltage would be 240-24=216, if it was 250v it would therefore be 225v. Now if the grid voltage was 220v and you stepped it down 10%, it would now be 202v and out of spec, which is bad for your equipment.

The way an inverter exports is to generate voltage above grid voltage, that way power flows out to the grid, now when power flow backwards through an optimiser it will step it up, so you could be liable for raising grid voltage far higher than 253v. Your inverter should limit maximum voltage, but it will have no idea it's exceeding grid voltage as it will only see the "optimised" voltage.

Optimisers are supposed to save energy, this is the real snake oil, in simple terms I don't see how they can, if your using 3000w it's the same at any voltage, ie current times voltage. Now I know there are things such as power factors, but I don't understand that side of things, so there could be a negligible benefit.

What I would do, I'd monitor the voltage both before and after the optimiser, if there was a problem with the grid voltage I'd contact the DNO, and see what they can do. I've done this a couple of times many years ago as our voltage was going above 253v in the early morning hours. They said they were going to install a monitoring device, but I don't think they did in the end and just altered the tap point on a transformer somewhere, one engineer told me they usually do it twice a year as routine.

Depending on the outcome of above I'd either leave it in, alter it's tap point or remove it. If leaving it in then you'd need to make sure your solar is not making the grid voltage to high.
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Great post Ron-ski. What tool did you use to monitor?

Right now I just feel like removing it. If it breaks in the future I will need to pay an electrician to come remove it anyway. But will do the test first as you suggested.
 
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I wonder if the DC coupled were not IP rated previously as my installer certainly said I couldn't have GE batteries outside, but I was always having DC.
Or maybe it was the inverter that was the issue, anyway it seems GE is now fine outside as ever stuff changes.

Do GE have heating option?, my only (minor) concern with external batteries is they may have issues charging in sustained cold.

You can help with that, insulation helped a lot on mine and ensuring you have discharge for late in the day helps keep them generating some heat where as if you drain them by say 6pm they can be sitting there for hours slowly cooling to ambient.

Your still recommended by most manufacturers to cover them if outside to protect from the sun. Its a requirement in some countries but not the UK.

I always resisted recommending solax until recently. I was far from impressed with the options, but they have worked a lot on firmware, the latest TOU stuff is excellent.
Allowing you to set charge and discharge rates as well as times, battery SOC targets and minimums by time etc, even different schedules for different days.

The Solax G4 system with matebox looks like a giant AIO but with more flexibility. I would certainly recommend them now as a competitor again.

Solax have added a battery slave master so you can double storage now (was limited to 4 batteries previously) now it can be 8.
Also added a addon box that has its own processing ability to do funky stuff so far more processing power than an inverter does itself.
Oh and lastly they also make Ev chargers which integrate and as we know some people have issues with Ev chargers not playing nicely with solar.
 
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TNA said:
Thanks guys.



Great post Ron-ski. What tool did you use to monitor?

Right now I just feel like removing it. If it breaks in the future I will need to pay an electrician to come remove it anyway. But will do the test first as you suggested.
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Back when I got the DNO involved I used the data logged by my UPS, today my Victron system monitors the voltage at the consumer unit, its actually the ET112 that provides the reading.

Here's yesterdays voltage chart. The big dips towards the end of the chart are the car charger turning on, and the house batteries charging, then when charging stops the system starts exporting until 23:25. Its about a 9v delta.

On your system you'd need a something from perhaps Shelly to measure and log the voltage, these will need wiring in though.

 
Ron-ski said:
Back when I got the DNO involved I used the data logged by my UPS, today my Victron system monitors the voltage at the consumer unit, its actually the ET112 that provides the reading.

Here's yesterdays voltage chart. The big dips towards the end of the chart are the car charger turning on, and the house batteries charging, then when charging stops the system starts exporting until 23:25. Its about a 9v delta.

On your system you'd need a something from perhaps Shelly to measure and log the voltage, these will need wiring in though.

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Seems like more work than it's worth. Would an electrician be able to easily do it? As it would be all done during a consumer unit upgrade.
 
Its very easy to check the voltage at any moment in time with a digital multi meter, but the only way to get a true picture is to log it over time.

An electrician may well have a device they can leave connected to the log it over time.
 
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Anyone in the Gloucester area have a company they’d recommend…?

I’m with Octopus, have two EV’s and like the idea of just letting them deal with it all knowing it would be fully compatible and work fine with them handling any issues, but I’d be interested to see just how much extra I’d be paying for the privilege over a local installer…
 
You could try these, he seems pretty impressed with them when they did the first install, he then had them back to add additional PV although they did it at cost for the YouTube video.

 
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Penfold101 said:
Anyone in the Gloucester area have a company they’d recommend…?
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Not local to Cheltenham but I used Spectra Solar and they install nationwide (https://spectrasolar.co.uk/)
Pretty reasonable prices and good aftersales support
I've recommended them on here multiple times before and some forumers have used them since with no bad feedback so...
 
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Mercenary Keyboard Warrior said:
Do GE have heating option?, my only (minor) concern with external batteries is they may have issues charging in sustained cold.
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Yes but only in software, if the battery starts getting down to the point it will no longer charge it will run some energy in and out of it to stop it dropping further.

GE has added some new smart tariff cards in their portal similar to what you mentioned. It can also pull data from the Octopus Agile API to get price signals to charge.

You also have native support with Predbat if you are into the whole Home Assistant thing.
 
b0rn2sk8 said:
Yes but only in software, if the battery starts getting down to the point it will no longer charge it will run some energy in and out of it to stop it dropping further.
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Thats crazy, so rather than fit some heating pads, they decided cycling charging and discharging from the battery and therefore the grid was a good way to keep it warm, just bizarre.
 
Ron-ski said:
Thats crazy, so rather than fit some heating pads, they decided cycling charging and discharging from the battery and therefore the grid was a good way to keep it warm, just bizarre.
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Pretty sure it was a feature added after the fact, the battery would have to be completely idle for a very long time for it to kick in. I don't think I dropped below 17C all winter but then the inverter is also in the same unit as the cells in my set up.

I guess it is one of those 'better than nothing' scenario's.
 
I guess that makes sense, they forgot to fit heating on a battery pack that's rated for external installation.

My battery heating didn't come at all this winter, and only twice the year before. Looking at my temperature history they've only dropped below 11c a few times, and never down to 8c where my heating comes on.
 
That setting only stops the battery going below 2c and is optional on the app. It was only added as an option fairly recently.

I've found battery heating is not really an issue down here as it doesn't get cold enough.
 
The year mine was installed, I saw many days when charging rate was impacted and even on a couple of days it didn't charge, there was a sustained week long or so spell of negative temps at night with low single digit temp days.*
I found it was very critical in regards not running out early in the evening/late afternoon. Adding insulation helped a lot but its only delaying cooling.

When you look it up the thermal store of energy in the materials used in batteries is really low. As in it takes a very small amount of energy to raise 1kg by 1c.
Stick that in a metal box, add in some damp, a bit of breeze and no heat being generated and they can drop very quickly, as in from my recollection mine was dropping 1C every 10 minutes when discharged.

* To add to this, when I bought mine I specifically asked about outside temps affecting batteries and was told no.
I logged a whats going on "ticket" with them and spoke to them on the phone and they said they were having issues with loads of systems not charging fully/at all. (Mine charged partly some days but couldn't get up to full speed within the charging window for example)
I got round it by spending a day manually playing with them and got them warmed up so they could charge fully over night.
They visited my property a couple of times to check the batteries and saw my insulation at the time, they asked if it made a difference to which I said yes and they checked my system logs online.
They started offering "carpenter built insulated battery boxes" later that year. I think that tells you everything ;)

There won't be many days when the sustained temps are close to zero, but we do get spells in the UK of that.
Thats when it will become an issue, especially if you have drained it well before charge time and its sat there with no chemical reaction taking place to generate heat.

Anyway as I said, technically a lot of (I cant say all I haven't checked all) battery and inverters say they should be covered from direct sun so you may as well do that.
Eg Solax says "Avoid direct sunlight, rain and snow weather." "Do not expose to strong light" Under installation precautions.
Givenergy AIO states "Do not install in direct sunlight or near water sources"

As I said its actually in legislation in some countries that outside inverters must be shaded, UK this does not apply.

Most installers seem to ignore these points. Which is probably fine if you have a warranty issue and they deal with it.
Should you end up with an installer who goes pop warranty could be screwed if the manufacturer deals with it and finds its been installed incorrectly.
 
This winter I have been on Octopus Go, which gives a longer charging window, so I'm now charging from 23:30 to 05:00 (the last half hour I use for balancing), my system also discharges 19:30 through to 23:25, it uses the full periods to charge/discharge at a lower rate. A side product of this is the battery stays warmer, but my batteries are in a garage, so that helps as well. There is no insulation around the cells, just a polycarbonate enclosure which did help a lot.

Looking at the last six months, the lowest outside temperature I've recorded was 0.4c on the 10th January at 23:23 (the batteries were 16c and the garage was 3.1c), its possibly been a little colder than that as I think the sensor reading is affected by the garage temperature, but it does show you how warm this winter has been. Future winters may well be a lot colder, so any batteries outside of the home really do need proper heating, and I'm in one of the warmer parts of the country close to the sea which helps keep temperatures up a bit, inland it gets a lot colder.
 
Yeah this winter was very mild, and having the batteries charging/discharging means they keep some heat being generated.

I forgot to post yesterday but I was doing a sneaky first BBQ yesterday so was in the garden semi bored for 30 mins, and one of the houses I can see (3 story) has panels that are quite old. No bird netting.
The old guy was hanging out of one of the velux windows with a long rod trying to push it up and down under his panels.
I am 99% sure hes got pigeons nesting under them.
 
Ron-ski said:
Only catch with that is he'd probably end up damaging the cabling.
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Yep thats literally what I said yesterday,
either damage cable so its doesn't work or worst case create a potential fire hazard short

Was outside 10 mins ago and there is a pigeon sitting on the roof just below the panels, between the velex and the single panel row above it
So if hes managed to dislodge the nest(s) they haven't moved on
 
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