Reddit mentions of 4 Feet Flexible Dual-Wall Adhesive Heat Shrink 3/4" BLACK 3:1 Ratio

If you have only a very small number of motorized blinds (I'd say four or less), then Hunter Douglas provides good options to wire them up. You can either install battery packs that need to be serviced every few months, or you can plug in a small power supply. Each of the power supplies can drive up to two blinds. But the extension wires that come with it cannot be longer than about 15ft, and they are not rated for in-wall installation. So, you'll have to deal with them probably being visible.

If you have lots of blinds, the wires look ugly, and you really don't want to take up a gazillion outlets. We have dual stacked blinds (mesh & black-out) in a few places. There clearly aren't enough power outlets to handle that.

Hunter Douglas for better or for worse runs their blinds on 18V -- and their tech support claims that the blinds are pretty sensitive to voltage fluctuations. This has a couple of awkward consequences. 18V power supplies are really unusual. Laptop power supplies would be perfect, but they are all 19V, which according to Hunter Douglas is not acceptable. And other common voltages are 12V or 15V, which are both noticeably too little.

Furthermore, the blinds have relatively high peak currents. Hunter Douglas told me to roughly assume that each blind can require up to about 10W. Took me forever to find a place that sells an 18V/180W power supply, as Hunter Douglas doesn't offer any solution themselves.

Of course, that's the raw circuit board only. You still need an enclosure. I went with a 12V enclosure and modded it. The enclosure is a great size, and you can even reuse the metal shield for the power supply, if you are careful. It also conveniently already comes with all the fuses that you'll need anyway. So, that saves you quite some work. But you do need some tinkering experience to swap out the circuit boards. You probably also need to order a couple of Molex connectors and you'll need to do some crimping and some soldering.

The next problem that you'll run into is that the enclosure needs a cooling fan, but as far as I can tell it is impossible to find 18V fans. I ended up using an ATTiny85 and a MOSFET to PWM the 18V so that I could safely drive the existing fan (make sure to configure the micro-controller for FastPWM, or you'll have to deal with an ugly humming noise!). And while at it, I also added a temperature sensor, so the fan only turns on, when needed. You also need a small DC-DC converter to power the microcontroller. And if you don't already have a way to program Atmel chips, you'll need to buy a programmer. EBay has lots of cheap options, too. All of this definitely takes some amount of tinkering skills that not everybody will have, though.

Overall, building a proper power supply and distribution box cost me just over $200 in parts. Not too bad. But the amount of time spent getting it to work was ridiculous. Especially if you add up all the time researching which parts I needed to buy in the first place. I really don't understand why Hunter Douglas couldn't sell ready-made power supplies for installing multiple PowerView blinds. Even if they charged $500 for the ready-made box, that wouldn't be entirely unreasonable -- and that would be a huge mark up and make them quite some profits. In bulk, each supply should cost less than $100 to manufacture.

The next problem is finding appropriate cables. At those low voltages, currents are going to be high, and if you have anything more than trivially short runs, you'll encounter significant voltage drops. Since Hunter Douglas said that sticking as close as possible to 18V is crucial, you'll inevitably have to install beefier wires. Hunter Douglas recommends 14AWG for powering up to two blinds, or 16AWG when powering a single blind. I had good luck with buying Monoprice in-wall speaker cable for this purpose. Get the four-conductor version to minimize the number of cables that you need to string.

Ideally, you want to avoid splicing the cables. And in many cases, if you plan carefully, you'll be able to do that just fine. But sometimes, splices are simply unavoidable (for instance, when joining 16AWG cables to an 14AWG cable). I find WAGO connectors work really well for this purpose; unlike wirenuts, they can be used both with and without ferrules. And they work well for stranded wires, where wirenuts sometimes fail.

The blinds have barrel connectors, and Hunter Douglas suggests buying plugs with screw connectors. That is a good suggestion in principle, but I find it is impossible to securely fasten the speaker cables in the screw connectors, unless you use ferrules. And that means, you'll also need to buy a crimping tool. And for good measure, you should probably shrink wrap the entire contraption afterwards. High currents means you want secure connections.

Ideally, you should run all the cables inside the walls. But that's not always possible. If you can't, then you'll need to staple them instead. Make sure to use the right staples. I asked my electrician to help in order to meet my schedule; in hindsight, that didn't work out so well. He sent me his apprentice, who promptly proceeded to run each and every staple straight through the cable. Ouch. We had to redo all the wiring.

Now, my next project is thinking of a solution to hide the Hunter Douglas remote inside of a Decora wall switch. The remote is OK, but it looks a little cheesy when wall-mounted. As I said before, PowerView blinds are fine in principle and they are probably better than most competing products, but they do feel a little unfinished at this time. When they do work though, they are really convenient.