Parts for battery powered boombox?

Apprenti

Member
2016-01-21 6:23 pm
Hi,

I want to make something like Thodio's wooden boom box (I have a background in woodworking) but I have no idea what parts I need. I'm looking at wattage anywhere between 10 and 100W, the speaker needs to be battery powered but rechargeable, and preferably easy to wire up. I'll be using full range cones (haven't decided which yet).

Could someone help me figure out a list of parts I'll need to make this? I'm mostly interested in this for the woodwork, and so that I'll end up with a rechargeable near-mid field portable monitoring system for recording out and about.

Also, I'd like to keep this fairly inexpensive, as it's not going to replace a proper monitoring set up (it's just for use with my macbook and my recording software).

Thanks a bunch!
Joe
 
parts you'll need

Hi Joe. I JUST did this for X-mas as a gift. Turned out GREAT!

Parts list (the major things):

1)lithium 18V rechargeable battery (they make them for wheelchairs)
2.)Charger (though some come with one, search E-bay)
3.) 50W (what it's labeled as, more like 20W but it's clean) Class D bluetooth board (again, search eBay)
4.) 2 fullrange 4" speakers (I used Focal's, work great)
5.) a piece of hardwood, 1x8x8Ft, enough to make entire project, might even get away with 6' depending on size
6.) brass threaded inserts (so you can bolt on back and take it off if you need to, you drill, put in inserts, and then bolt back piece of wood into them)

That was is except screws, glue, and a LOT of labor.

How do you press the buttons on the board once it's inside the box? Check out what I did:

The board in my hand is the same one in radio, I had 2. put those long bolts through and bolted the board up near top. Got some nylon hollow inserts and some nylon rivets to use as pushrods. Then you just glue something flexible over the top to hold in the pushrods. Bingo! Now you can use all the buttons, and your board is completely hidden!
 

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Getting the recommended 18 volts is a good idea. Fairly stout 18 volt batteries are probably growing on trees near where you live if you know what trees to look at. Two words: Power tools.

General tip - Lithium batteries are made up of collections of individual lithium cells hooked in series. So, its usually possible to disassemble a commercial battery with a higher voltage and pull out just the cells. Typically the cells are hooked together with welded strips of metal.

In the US we have battery stores that make up custom replacement batteries and have the right kind cells in stock and an on-site spot welder for hooking them up into batteries.
 
yes, that's right

So, I'm not sure about that particular board but I'm sure you can research it. A lot of the boards have onboard voltage regulators and therefore like to have a little more voltage than 12 (better the drop volts in regulator than try to make them). My board likes at least 18....if it's not for portability and it'll be stationary just get a laptop computer PS, guys have good luck with that board and those, I know that much. I also know that board has good reviews....

I take it you're not going Bluetooth but instead wired? That's fine, that board has a 1/8" stereo input.

Those speakers, yes, they are definitely nice.

Also, think I remember on that board, people complained about the volume being a cheap part easy to break?

Check out the reviews for it, the Bluetooth board is not any more $, there's lots of types, all cheap if you shop around.

The last post was absolutely right, lithium rechargeable batteries in power tools, in other scrapped bluetooth speakers, in cellphones, etc. You can wire them in parallel, and then wire those parallels in series to get 18V. I recommend paralleling at least 3 for every 3.7v cell, then 5 in series for around 18. Also, 18V is an easy value to find chargers for and you need a special charger for lithiums.

That board, it's on parts express I know, I also know they have another not much more $ that has bluetooth, 1.8" stereo, AND is much higher wattage. I think you might be disappointed with the one you picked out. Remember, 15-20W = more like 3W before serious distortion sets in, and you need some power to those speakers as the efficiency is not terribly high, AND your box size is limited.

Loren C.
 
I just ordered a new amp from Sure Electronics that sounds to much of good deal that im wondering if they have cheaped out on the audio part, havent receieved it yet, but the board is either 2x 30/50w (Depends on what one you get) with Aptx bluetooth, which is normal BUT it has built in charging curcuit for lithium batteries (and SLA batteries) MPPT curcuit. The link is here Sure Electronics' webstore 2 x 50 Watt 4 Ohm Class D Audio Amplifier with Bluetooth 4.0 APT-X-TPA3116

Its something to look at