DIY battery operated stereo

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Hello to all:

I am attempting a 2 channel or 2.1 channel diy batt. Powered bluetooth boombox. I've been researching deep cycle lipo and nicad Batts to power the receiver. And I ran into an area of questions I can't answer without buying some gear or asking a forum full of experts. So I'll attemp the cheapest option first:

Links to setup #1-

JVC KD-X330BTS Digital media receiver (does not play CDs) at

Links to setup #2

JBL GT7-4 GT7 Series 4" 2-way car speakers at

My questions are:

1. When both recievers draw energy how much in watts does each one consume?
2. If this is conditional solely on speaker power (and not the recievers) I read that spl levels are between 86db to 9o db at 1 meter/1W. Does that mean that my speakers only draw 1W individually at said decimal level? If not, then estimates? Any insight in my endeavor would be greatly appreciated

Mike :)
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Speakers dissipate 99% of energy into heat
<well, you might find speakers going from 0.3 to 4-5 % energy conversion factor> but when going little, lower than 5 " diameter in size, the SPL is rather low: the important data is the sensitivity one and it is expressed in dB per Watt per Meter ( dB/W/m), when you apply one Watt to an 8 Ω speaker, which equates to apply a voltage of 2.83 V, or 2.0 V to a 4Ω speaker.
Please define your needs a little more: is it a couple pounds weight shoebox sized boombox to be used indoors or within a couple meters outdoors or a full sized beach/park party machine for a lot of people?

Because here in DIYA there is a looooong thread dedicated specifically to a large portable boombox project:

Even if you build a small version, that thread will give you lots of ideas, plus lots of actually built and used projects.

From your suggested options I'd choose the JVC receiver with its "22W" per channel power , maximum you can get from a 12V battery, and the high efficiency Faital Pro speakers, but in a somewhat larger size: 4"or 5" and *forget* subwoofers, period.
Power hogs, very low efficiency (82dB vs Faital's amazing 91dB) , and no real bass anyway because they won't match the Faital much louder sound.

Live with the Bass these can give you which is very good anyway and enjoy wall shaking pants flapping bass at home, in mains powered equipment.
Everyone thanx for your input. @JMFAHEY -- I planned on a heavier box but one that was 40 lbs max. I was concerned with power consumption because I wanted to use rc nicad/lipo Batts. I've found to moderately priced options in lipo 12v for car stereo with 20-25 ah 360cc or two 20v Batts in parallel with around 25 ah
Here's the links:
Battery Tender Lithium Iron Phosphate 12V 24AH 360CCA Replaces Yuasa YTX20HL BS | eBay


6 of these but I'm wasn't sure about power consumption per hour at 90 db
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The signal side (player/preamp) won't consume much.

Seat of the pants estimation: the power side will eat roughly 50% more than actual max. power out but , say, halve that because music is not a continuous tone, so 2x22W RMS amounts to 44*1.5*0.5=33W

If supply: 12V current consumption: 33/12=2.75A
Round up to 3A because of the player.

So if 21AH available and you use 3A continuous battery life is 7 hours.
Not bad.

Forget the subwoofers ;)

What does
an 60 watt down throw witch hits 90 db at 35hz

If you think a 4"speaker can hit 90dB SPL at 1 meter at 35 Hz, none will, neither driven at 1 watt nor 22W, just read the curves.

The Tangband which is a 5" subwoofer shows 75dB SPL at 1W and 35Hz; so needs 15dB more for 90dB, some 32W RMS ... and that IF it does not run out of excursion first which is the real problem.

A 4"or 3"? ... don't even try it.

Again suggest some of the lighter Boominator projects, they come in all sizes, only problem is browsing the long thread ;) but they certainly experimented (collectively) way more than any of us can.
I use this type of 12 volt battery. Each comes with a charger and they can be easily connected in parallel to double the capacity..

2015 New High Quality Super Rechargeable Protable Lithium ion Battery EU Plug for DC 12V 15000mAh-in Rechargeable Batteries from Electrical Equipment & Supplies on | Alibaba Group

I get great results with this combo. Operates on a 5 volt bank battery for many hours and sounds very good with a little tweaking.. ;)

Add a strap handle to the top, some way to house a bank battery on the back and you're rockin'..

New Mini Bluetooth stereo digital amplifier AMP micro USB powered 2X3W board module free shipping-in Other Consumer Electronics from Consumer Electronics on | Alibaba Group

A pic before I had it completed..


MCM Audio Select 8" Weatherproof Coaxial Speaker w/1" Tweeter | 55-3025 (553025) | MCM Audio Select
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