Battery-Powered Sonos

Sonos gets beaten up because it lacks a battery-powered product.  Well known for its focus and a conservative product line-up, Sonos requires you to take a plugged-in extension cord wherever you want to enjoy the system – such as on your deck or by your back-yard pool.  My own experiments with battery-powering a PLAY:1 give insight on why Sonos is stubborn, besides just their determined desire to own the domestic space (rather than audio in the car, or on the beach for that matter).

Play1BlkFront_Large

Sonos lives and dies by its network, and Sonos products turn into lumps when off the network (except for the Soundbar, arguably).  While I could see a future where a farther-away (across a large yard) Sonos unit is synced via a cell connection, I doubt that’s happening soon.  But also as a person who has lugged a PLAY:5 to my outside deck for a cookout, I had to explain to guests why I also needed that AC power extension cord.  The PLAY:5 even has a nice handle integrated with its tuning ports, and it sounds pretty good outside.

For my experiment I tried the lower power PLAY:1 which also sounds good outside, near the house and its Sonos network.  I have no desire to take the PLAY:1 to the beach.  My goal was to see if battery-powering the system was practical and sounds good.  The quick summary is that there are issues with both.

The Experiment

For the test I used the PowerBank Elite 25 from Nature Power which sells in the low $200 range.  This power pack is about the size of a medium sized hardback novel and weighs about the same.  The product’s primary purpose is to recharge phones/tablets through its three USB jacks, or to recharge a computer through its 120VAC plug.  (I’ve used the unit to charge my laptop computer this way, and it works well.)  To keep its cost down, the product is designed to create a simulated sine wave, meaning a choppy stair-step version of the nice smooth undulating sine wave you learned about in math class.  The result is that this “unclean” power tends to cause noise in audio products, and can even damage some types of products.  The PLAY:1 is well behaved, function-wise, but is not immune to this noise – a low-level midrange-frequency buzz that would annoy you in a quiet room. Use the system outside, playing music, and the buzz is generally masked.

PowerBank Elite 25

PowerBank Elite 25

(Clearly if Sonos made their own battery-powered product, they would not use my convoluted DC-to-AC-to-DC set-up… they would design the circuits to run straight from the battery, for far better efficiency.)

Speaking of Efficiency

I learned some interesting traits of the PLAY:1 through my testing.  Sonos rates the standby power as 4 watts, meaning that the 93.2 watt-hour PowerBank will run the unit in standby only for about 24 hours before it goes dark – and you haven’t even played any music. So clearly you want to unplug this set-up until you are ready to use it, to avoid battery drain.  Sonos doesn’t rate the normal running power of the system, but based on run-down tests with the battery, I estimate the core PLAY:1 system consumes about 10 watts, even when playing quiet music.  In fact for levels up to about 75 dB (at 1 meter), the system only uses about 10 watts, so that 93.2 Wh battery gives 9 hours playing time. Bump the sound level to 85 dB (getting fairly loud for a single PLAY:1), the system consumes enough to shorten life to 7 hours.  Go to 95 dB and you get 2 hours.

Winter outdoor testing in New England

Winter outdoor testing in New England

So this brings to light the real reason a battery powered Sonos is a challenging product to make.  First, the baseline running power, for the network circuits, audio circuits, buttons, and lights, is pretty high.  Second, to give the product its bad-ass performance (good bass, good dynamics, especially for a small system) they gave it a powerful amp, far larger than is ever seen in small battery-powered systems.  Surely Sonos will someday have a battery-powered product, probably with great performance, though some combination of efficient transducer design and efficient power supply / power amp design.

Would you buy this product?

I’ve wondered whether – despite the power consumption – people would pay for a PLAY:1 battery-pack carry-bag as an accessory product.  As a product designer, I’ve even researched the cost of making such a product, with the proper clean sine wave for good sound.  It’s not cheap (take note of the battery cost I mentioned above.)  I am curious, how much would YOU pay to carry your $200 PLAY:1 out to the deck or pool, without attached wires, within range of your Sonos network?  Comment on this article, or email me, and maybe (just maybe) I’ll make you a product!

© 2014 Stephen Shenefield

19 thoughts on “Battery-Powered Sonos

  1. Stephen , that is a great article and can understand why developing a battery pwered unit is probably low on the Sonos research list . I have never been interested in a standalone sonos unit but I would definately be interested in something similar that I know has been requested by many as well as myself .
    I apologise if you see this as going off topic .
    Regards
    Keith
    Could you relate your research above to the requirements of using headphones as a Sonos zone so that I can wear around the house. Obviously Sonos would have to shrink their hardware but key would be a reasonable battery life of say at least 5 hours before needing recharging and without being too heavy !!!!!

    • Hi Keith – thanks for your question – There is good news and bad news. And an alternate strategy…

      Following the issues I identified, the good news is that typical headphones don’t consume much amplifier power, so my observation of shortened battery life reduction at high sound levels just wouldn’t apply at all. The bad news is the baseline 10 watts consumption I observed on the Play:1 is a lot for a battery system you would wear on your head. For instance, a single Lithium AA battery has a capacity of about 5 Wh (it can put out 5 watts for an hour). Two lithium batteries would last an hour, roughly speaking. Of course, the Play:1 is not optimized as a battery-powered design.

      The core issue is that each Sonos product is a little Linux-based computer, and Sonos’ current network strategy (I am guessing here) requires that all units participate in their “mesh network” – where any unit can in effect be a signal repeater, bouncing the network connection to a farther-away Sonos unit. I suspect that to make headphones, Sonos would have to come up with a very low power consumption version of their zone system, as well as make the headphones an exception to the mesh strategy – the headphones could be a network node on their own.

      You may already have tried this, but for now I think the best way to enjoy wireless headphones with a Sonos system is to use Bluetooth headphones with a Bluetooth transmitter ($20-60) plugged into the headphone jack of a Play:1 or the line outputs of the Connect unit. Similarly, a wireless headphone system with its own proprietary wireless transmitter would also work – many of these have long enough range to work throughout the house. Many wireless headphones systems sound quite good (read the reviews). Digital wireless systems introduce a small amount of time delay, but I am assuming you would not also play other Sonos speakers when you listen to headphones.

  2. Stephen

    I would definitely by a battery powered Play 1. In fact I was googling such a thing which is how I found your article.

    I have (and a number of friends have something similar) a deck at the bottom of my garden, as this gets the sun towards the end of day (the deck behind the house is in shadow after 5pm)

    I would love a have a portable Play1 that I could carry out to that deck on a summers eve.

  3. Well, the article is good. But, I’d be buying a powerbank instead. Since it’s more convenient to use. Not all powerbanks do offer actual battery capacity. But I know one company that offers an actual one (battery capacity).

  4. Do check this out:
    http://tweakers.net/productreview/98600/sonos-play1-zwart.html

    It’s not in english but the article had made significant progress on running Play:1 off batteries/portable power.

    The concept was through identifying Play:1 has AC110/220v step down to DC24v before stepping down further and distributing the respective voltage requirement to the various components. In that regard, it means you can power Play:1 with a 24v power supply or any portable power options using a step up/down transformer.

    Issue is the article didn’t state (or my limitation of comprehending the article) the line or point to inject the DC24v power.

  5. I have a sound bar, sub and Play:1. While I would love to add to this collection, I’ve been holding off for Sonos to release a battery powered version. Alas, your article has done a tremendous job of explaining exactly why this may remain a dream, at lest for the foreseeable future. Great article, well researched and written, thank you.

  6. I would pay between $49 and $99 retail depending on capacity. Throw in solar charging and you could def get $99+. but its probably a matter of time until sonos does it themselves. playbars will get them into more homes and new prods have to follow.

  7. I have been looking for a portable solution and was searching for power ratings when I stumbled upon your site. Looks like I’m late to the game but thought it was worth dropping a comment. Seems to me the price point should be between $150-$200. I’ve been looking at the Duracell Powerpack Pro and ChargeTech – 27,000mAh BLACK Portable Battery. The ChargeTech specs say “Built-in AC outlet will power any standard electric device *UP TO 65W*”. But now I’m wondering about how clean the signal would be. ChargeTech is nice because it’s small but not knowing a lot about power, I’m uncertain if it offers what is needed to power the Sonos1. The Duracell looks big but I’m guessing there is no issue with providing enough power. Have you looked at the ChargeTech? Do you think it offers enough power?

    • I haven’t looked at the Chargetech – the clean signal is the key – and if there are a lot of messages on the company’s website about “not compatible with certain audio devices then you may need to be concerned. As for power, most listening is done with far less than 65W running to the speaker.

    • Interesting, but not really relevant here! This Sonos product runs on AC mains power only. Power systems for these are much more rare. Thanks for the comment anyway.

  8. Hey Stephen, just read the article, would the Xcellon 12,000mAh Power Bank with AC and USB Outlets B&H # XCPB1200AC MFR # PB-1200AC work? It came up on a Google search for me.

      • Hi Stephen. I have made such a thing. It allows the play 1 to be run from the mains or the battery pack. However it does require opening the play 1 and hooking up to the 24V DC power input, bypassing the mains transformer. I then run the 24v input to a female DC jack and mount this in the base of the unit, so that either the mains connector can be used or the DC jack, but both cant fit in together which covers the safety issue of accidentally plugging in both power sources! This 24V DC jack is then connected to a step up converter that turns 12V into 24V. The 12V is supplied by a £30 12000mAh USB 5v & DC 12v/16v/19v power pack. All the items cost less than £50 in total and I can run the play 1, from the power pack alone, for over 5 hours, with the volume set to around 80% (extremely loud!). Photos available.

        Cheers,
        Nick

      • Wow Nick that’s great! Glad to hear you solved it. Thanks for writing in with all the details.
        Cheers,
        Stephen

  9. I was considering what it would take to bring my Sonos One to the park, but just to expand on the potential business case: I guess one can just create a wifi hotspot on the smartphone, then run the One far away from the home network. Maybe not such a bad idea to make a battery for these kinds of applications.

    • Regarding taking a Sonos “to the park” I would be interested if you succeed. I have never managed to configure a Sonos system so it uses a phone as a hotspot network and receives audio wirelessly. Of course, you could always wire to the line input if you are using a Sonos model that has it. My experiments with battery power were more focus on the use case where you are within range of your wireless network (wifi or SonosNet), such as in your back yard.

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