Deep Woods Rockin'

August 12, 2008 7:17 PM

I'm looking for a simple "let's listen to music while we're camping far away from our cars" power solution.

I have an iPod and a pair of portable Sony SRS-Z500 active speakers (with a regular old AC plug) that I think could do the trick if I could buy a magical box that would hold a thousand D-Cell batteries and have a regular old AC outlet on the front.

There won't be an outlet (obviously) or any cars around. I don't need it to run for a month...maybe 8 hours of total music playback. I'm not MacGyver and to me the word "Ohms" sounds more like a Buddhist mantra than something from physics class.

Am I looking for a Power Inverter? Or some kind of battery pack? An Uninterruptible Power Supply? Links to specific brands or manufacturers would be appreciated.

[The Sony Speakers say Input: AC 120V 60Hz 20w and Output: DC 9v 1100mA :: Class 2 Power Supply if that helps]

posted by Overzealous to technology (19 comments total)

Are they the ones that don't have to be plugged in? I have some portable speakers I got from Radioshack that sounds a lot better if turned on/plugged in, but work if they're not.
posted by theichibun at 7:22 PM on August 12, 2008

@theichibun - Yep the speakers need to be plugged in...no onboard battery supply.

@Listener - Thank you for your positive and constructive comment. Please rest assured, I'm not re-creating Pink Floyd Live at Pompeii, I just want to have some music in the background during my parents' 60th birthday party.
posted by Overzealous at 7:41 PM on August 12, 2008

There are solar backpacks and mats that you can get. Not cheap, but terribly useful! A google of "portable solar" had a pretty wide array. This was the coolest I saw.
posted by sadiehawkinstein at 7:45 PM on August 12, 2008

All you need is a 12V source like a car battery and an inverter. The smallest you can get go down to around 40Ws which should do you and they are available in lots of places including Wal Mart. Pretty useful item so you might want to consider a 75-140W unit for future use.
posted by Mitheral at 7:49 PM on August 12, 2008

How about a car battery that you charge up ahead of time, then hook to a DC to AC power inverter ? 75 watts should be more than enough of an inverter. Since you're powering audio equipment, you wouldn't want to pick the cheapest one out there - you might get a lot of hum. Look for a pure sine wave inverter.
posted by rfs at 7:53 PM on August 12, 2008

Oh well, I'm too late !
posted by rfs at 7:53 PM on August 12, 2008

Something like this Duracell Powerpack 300 or the Xantrex Powerpack are close, but may be overkill...
posted by Overzealous at 8:16 PM on August 12, 2008

Years ago I used to get through power outages using an UPS. They're not just for protecting a computer... you can power a boom box (or any low-draw AC electronics) for hours.

I'd imagine you could get a used one dirt cheap on Craigslist (like $10) that's too weak to power a computer but would work your electronics all night since we're talking an order of magnitude lower in power consumption. Just make sure the outage alarm can be silenced.
posted by crapmatic at 8:28 PM on August 12, 2008

We have one of the Xantrex Powerpacks and I have to say that it has come in handy many times, especially for checking tire pressure and jumping a car once. It might be handy outside of this particular application for you. However, it's not the lightest thing in the world, so that might be something to keep in mind as it sounds like someone will need to haul it out to wherever you're going.
posted by stefnet at 8:35 PM on August 12, 2008

12V DC -> 120V AC -> 9V DC conversion is going to be inefficient. If you wanted to go straight DC, there are also things like this battery pack, which is already 9V (so no losses) and comes with 5 different tips to plug into your device. The risk is that none of those 5 fit your device, and you end up visiting Radio Shack to find the proper tip and potentially doing some splicing of cables.

However, that Duracell Powerpack has 14Ah of power, which is probably enough for your needs, assuming the losses in the conversion process aren't huge. 14Ah = 14,000mAh, which means your 1100mA speakers could run for 12 hours at full volume if there were no losses in the inverter and transformer. I'm guessing efficiency is probably 85% in the inverter and 75% in the cheap AC-DC adapter for the speakers, meaning overall efficiency of around 63%, leaving about 8 usable amp hours — still plenty for your needs. And it has the benefit of being a generally useful device to keep in your car for future use.
posted by knave at 8:39 PM on August 12, 2008

Have you considered looking for a portable stereo that has an input for your iPod? It seems like any power solution would cost ass much as a pretty basic boombox (if they still call them that.)
posted by advicepig at 9:10 PM on August 12, 2008 [1 favorite has favorites]

I am a total evangelist for the Sonic Impact T Amp. I got mine for about $40 but I think people have caught on since then and they're selling more expensively - though there's an eBay auction for a second generation T-Amp currently standing at $30.

Why am I recommending this and what relevance does it have to you? It's a tiny battery powered amplifier, maybe about the size of two cigarette packets, that is capable of driving normal stereo speakers. It runs on AA batteries, so you don't need to plug it in anywhere.

All you need to do is bring along the speakers and the iPod/s. It can drive small speakers or big speakers...obviously the sound quality and volume you get is depends on the speakers themselves - the better the speakers (and often the louder the speakers), the more you'll get out of the T-Amp.

But it's significantly better than any of the portable speaker solutions that are sold as iPod accessories, and much better than any boomboxes I've encountered. Basically you get sound as loud as a home stereo but from a tiny little box.
posted by skylar at 1:11 AM on August 13, 2008 [1 favorite has favorites]

it's significantly better than any of the portable speaker solutions that are sold as iPod accessories

With one exception, perhaps? I cannot adequately express my love for my iMainGo which is indescribably better than any other portable iPod speaker. Forty bucks, plus a good supply of AAA batteries, and it sounds as good or better than any active speakers I've ever owned...
posted by game warden to the events rhino at 4:17 AM on August 13, 2008 [1 favorite has favorites]

Game warden, It is for a party. Personal speakers won't cut it. There are several boom boxes that have AUX in connectors, or iPod docks. A whole bunch of D cells and you're on the road to PARTY!.
posted by Gungho at 4:27 AM on August 13, 2008

Personal speakers won't cut it.

Point taken. But if you ever get a chance to listen to an iMainGo, do so: I've used it at gatherings of 10 - 15 people (admittedly not a huge number of people) and always receive completely blank looks of astonishment when they see where the sound's coming from...
posted by game warden to the events rhino at 4:32 AM on August 13, 2008

Game Warden, the speakers you link to don't have the power that I'm talking about. The solution I suggest above with the T-Amp is like having a very powerful home stereo, with very loud speakers, but in a form factor that will fit into a large pocket or a small bag. The T-Amp is even louder and better quality than most boom boxes or iPod docks, precisely because you can drive big speakers from it if you want.
posted by skylar at 5:25 AM on August 13, 2008

Second the T-Amp. It is a battery-powered amplified that competes favorably with 120 volts high-end amplifiers, both in sound quality and in loudness.

The company that invented the chip seldom licenses its patent, so their Sonic Impact amplifier is the only game in town.
See http://en.wikipedia.org/wiki/T-amp
posted by gmarceau at 6:50 AM on August 13, 2008

The T-amp, some efficient speakers and a smallish 12v battery would be a good solution, but alotta hassle to carry and set up, compared to just buying/borrowing a middling D-cell-eating "boombox" with an iPod-ish audio input. (It's also fairly easy to hack a temporary iPod input across the volume control of most old portables, if you speak electronic)

It's just a party ;-), not a mix session, so any sound is good sound, IMHO.
posted by Artful Codger at 10:18 AM on August 13, 2008

In the end, the boombox with aux input may be the best (portable, loud enough, runs on batteries, iPod-compatible) solution. Thanks Mefi!
posted by Overzealous at 1:21 PM on August 13, 2008