Alan Ambrose

OK ta.

Should the max MPPT voltage be compared against the panel's open-circuit or max power voltage? For the panels I'm looking at (JAM54D41-445/LB) the max power voltage at 32.65V is only 83% of the open-circuit voltage of 39.1V. I'm pushing the max MPPT voltage with the number of panels I'm thinking of, hence the question.

I found a few scraps on info for anyone coming across this thread. Summary is that you can control either by linking up via Velux's propriety RF interface e.g. + Documentation - Velux | Loxone + Velux - Home Assistant Yuk. The more grown-up solution is via a custom PCB: + Controlling Velux windows | SmartHome.Exposed + Module VNX-A for interfacing VELUX® KMG100 window actuator drive Curiously, Google AI thinks this (which seems to be nonsense unless this is maybe for some non-retail Velux products): VELUX 24V control systems are Open System solutions for controlling electric windows, blinds, and vents via a ±24V DC signal, allowing integration into building management systems. This is different from the company's proprietary io-homecontrol system and is often used in commercial applications or with smart home systems that support this voltage. You typically need a compatible building management system and hardware like relays to control the devices. How it works Voltage: The system uses a low-voltage ±24V DC supply, which is a standard in building automation. Control signal: You send a polarity-based signal (positive or negative) to open or close the window or blind. Integration: This allows you to integrate VELUX products into your preferred smart home or building management system (BMS). Hardware: A building management system can control the devices through hardware with relays that switch the 24V DC signal. Devices like the Velux KLF 050 or KLF 200 interface can also be used for this purpose, or you can use a system like Loxone with appropriate relay extensions. Key components VELUX products: This includes electric or solar-powered windows, blinds, and ventilation modules equipped with a 24V actuator. Control unit: A building management system or a specific interface (like the Velux KLF series or a Cartelectronic interface) that sends the 24V DC commands. Power supply: A 24V DC power supply for the actuators and control system. Relays: In many cases, a relay is needed to switch the 24V DC polarity to control the motor. Example scenario A smart home system (like Loxone) is connected to VELUX windows via a relay. The system sends a signal to the relay, which then applies a 24V DC current to the window's actuator, opening or closing it based on the polarity. This allows for automated control of windows based on time, temperature, or other inputs within the smart home setup.

One of the next few Thursdays maybe? IP14-ish but feel free to make suggestions. Or maybe if we're very nice to @G and J he might resurrect his Woodbridge offer?

This is Artisan Electric's view of battery options from a year ago (below). I'm leaning towards the Sigenergy stuff. Anyone have a very different view or some more nuanced observations? I'm looking for single phase, adaptable 'open' system, to bolt into Home Assistant or similar. From: https://youtu.be/7xQGexleUfQ

>>> A last gasp 2025 meeting before the Xmas shenanigans start? @G and J @marshian @GaryChaplin @LSB @JohnnyB @zzPaulzz @pilgrim Apologies if I've missed anyone.

It’s also instructive to rotate the laser in 8 x 45 degree turns and see how the horizontal line varies. You can compare that against the spec bearing in mind that the spec is usually for the diameter of the circle being traced. That gives you a real feel for the wobble in the beam.

Well he is an Electrician .

I’ve used about a dozen tubes of Orcan F already. It all feels a bit dodgy to me. It seems to be water soluble, it doesn’t seem to set, it doesn’t seem to be particularly sticky. Is it really just low quality gunge? Besides apparently winning lots of prizes PriClima’s blurb says ‘The adhesive joints created must not be subjected to tensile forces.’ Does that mean that if a crack widens up (cracks often do this, duh), all bets are off? I’m using it to ‘seal’ joins in a ply skin right now.

Thanks @Post and beam - for later readers of this thread, watch about 20s from here to see how these assemble:

Anyone have a schematic or a simple explanation of how to wire an electric Velux plus electric external blind? I really want a wired set-up and no RF or batteries or remotes and preferably 24V. Are these 24V internally with a 240V transformer on-board? Is it possible to wire only for 24V operation? Yeah, eventually for Home Assistant software or similar. Something like a 6-wire set-up (i.e. 2 off open and close) to some relays?

Ah, yeah, now you point it out, it looks likes it designed for that way up. They might have said... or had a picture like that on their web site. Maybe their marketing people didn't understand it either. I see that the Valve Adaptor Extension says 'Simple to cut to desired length for seamless customization' so presumably the ribs on the Valve adaptor are meant to indicate that you can cut it to length. And, hey presto, it has a picture of the valve adaptor hanging from a magic support above the ceiling and ending up flush with the ceiling plasterboard. That's clear then...

>>> I have CCT LED's in three skylights Ah, very clever

>>> so a floor rather than a ceiling and then just gets screeded in place Ah

Jeez this must be harder than necessary and I can't see any instructions on Ubbink's site. Ubbink tech support seems to be one man who's main policy seems to be to ridicule whatever you want to do. If you take him as his word, even though Ubbink have them in their product portfolio and sell them, half of Ubbink products have no useful function. Also, some retail outlets are quoting 15 working days i.e. 3 weeks delivery (e.g. https://www.ventilationland.co.uk/en_GB/p/ubbink-air-excellent-48c-valve-adapter-125-1x90deg/27952/ ), but tech guy says he's sitting in the Midlands right next to a huge UK shed full of product. + This valve adaptor. It doesn't have obvious fixing points or instructions. Do people cut it off at one of the annular rings and mastic it into position or use that odd horizontal piece on top somehow? Both? + I wanted to use this kind of valve to balance next to the manifold rather than at the terminals, but this exists only in 75mm AE34C size and not in 90mm AE48C size - which, of course, is the one I'm using. And there's no AE48C to AE34C adapter.

>>> I think it would be sensible to put the SPDs for the solar in the connection box, two breakers and then on to the ground floor plant room to the inverter. The regs may not be totally clear, but I believe there’s a qn re DC isolators before the inverter. See e.g. This text and audio (there’s a video too) is one year old; https://electricalnews.efixx.co.uk/1978879/episodes/14269857-don-t-install-dc-isolators-on-solar-electricians-warned This video quotes the regs but is 2 years old;

>>> On my clamp meter I show 4mA leaking through the main earth bonding leaving the board. That’s a good test, but is that with all the other MCBs off? Check that reading on each circuit by switching the MCBs on one-by-one to double check which circuit(s) the leakage is on? Similarly, take your suspect box out of circuit temporarily by taking it out of circuit? That is, binary search until you prove to yourself exactly what circuit / box / connection / device is causing the majority of the leakage.

@-rick- Yeah, following the discussion above, which is very interesting, I’m tempted to use 24V CCT LED strips up high and shining upwards onto the ceiling so you can’t see the LEDs directly, only the reflected light. We have this kind of directed light in our present place but using ordinary cheap spotlights. I might lean towards central 24V power with the controllers all in one place and run control wires from the physical controls (just switches & volume knobs, nothing fancy) from the rooms to the controllers. Add a bit of scheduled colour control by app like @Stevieb12345 has done. I see that Loxone (I won’t use those, crazy expensive) has max 5m 24V strips, so I’m planning wiring around the same lengths. A couple of positions for pendant lamps (24V CCT if we can find them) and we’re done 😃.

@Stevieb12345 can I ask what hardware you use to drive the strips? All on separate power supplies, or from one?

It could be that they’re not wired in properly. Eyeball where they’re connected in and/or check with a meter.

A last gasp 2025 meeting before the Xmas shenanigans start?

Yeah ask and get a QS to calculate for comparison. The latter should cost v. little if you give them a schedule of the bits. Or, get a steel shop to give you a quote from the schedule - offer to pay them for that maybe?

I never understood this either - is it better to have a 12-hour delay (so the phase shift partially cancels out the temperature driver) or as long a delay as possible (so the inside is as unaffected by the temperature fluctuation as possible)?

That's both impressive and resourceful. I am curious though - why did you push two ducts through another duct?

Ah thanks. Reporting back, there are a few other manufacturers but none seem to have an energy rating better than 'C'. They're all about 2m long by 0.55m diameter for 300L.