Laptop Battery Technology in a BoomBox Stereo?
 

Hi Guys,

I just snagged one of these off the Bay.

http://i160.photobucket.com/albums/t...asonici931.jpg

I'm pretty excited about it, since it's loaded with features. It will accept an Ipod, or any Mp3 player, but since it also accepts Memory Sticks as Mp3 media, that's probably what will be used the most.

It also has a remote, which is pretty cool.

The nostalgia factor is also really nice.

All of it's features isnt' really what this thread is about though.

A Laptop has it's own lithium ion pack, with cell protection. You don't have to take out the pack, or plug it into to a separate charger. You don't even have to make a conscious effort to charge it. It just does it automatically.

This Boombox takes 10 "D" size cells. We all know it's gonna eat those for lunch. No I say! Let's make it better. Let's put it on Lithium Ion.

Now 10 expensive "D" cells fresh out of the pack will be 15 volts.

There is an acceptable voltage range of operation on this unit, so before the unit starts cutting out from low battery voltage, I'm thinking this will occur around 9 volts or so.

I'll be sure to check the AC transformer voltage to double check. But I'm thinking it will be a regular 12 volt transformer.

This puts things in line for 3S Lithium/Lipo operation.

Lipo can be used as long as it has some sort of protective circuit board installed that monitors voltage.

I thought about this route until I acquired a quantity of "new" old stock on some cell phone batteries.

That's when I came up with this.

http://i160.photobucket.com/albums/t...m/DSC07893.jpg

Each cell phone battery has it's own pcb. Eureka! That problem is solved.
The picture shown is a 1S configuration at around 30,000mah. I will build another pack similiar to this, only in 3S configuration. Totol Mah of the new pack will be determined by battery compartment size. (How many will fit) LOL

Now, we want a separate charge circuit that keeps the battery pack topped off for as long as the unit is plugged into AC.

When the unit is unplugged, it will run on the Battery Pack.

As soon as the unit is plugged into AC, charging will resume, without pushing any buttons or anything.

I have a 1 amp lithium charger that plugs into the wall. It's not a balance charger or anything like that. It is simply constant current up to 12.6 volts (3S).

I plan to install the charger inside the BoomBox, wired to the incoming AC power.

Question: When the unit is unplugged from the AC, will the charger transformer drain energy from the battery pack? If so, what diode configuration will cure this issue?

What do you guys think? Please feel free to chime in and express your opinions/ideas.

Holy shizzle.

That's quite the power pack there, great idea using cells with built in protection, should get you a few minutes!

I hope you have Electric Avenue in your library, or something of similar vintage lol.

Okay so first that thing just brought back memories.........

We need a link to where it came from. I remember as a kid strapping a radio to my bike handle bars jammin to the Beasties and all that fantastic glam rock!

Nice idea on the batteries, hopefully it turns out well!

Its a Lasonic i931 Ghetto Blaster.

Search for that on eBay and you'll find it.

+1 Yes! :yes:


You can also use searchwords...... Lasonic Ipod

Amazon carries them and so do several other sites.

Here's a site that has a review on them, for those interested.

http://gizmodo.com/381663/review-las...erdict-awesome

Once done, a complete and detailed materials list and complete instructions on how to ''go ghetto lipo'' so that idiots like myself can understand will be required. Thank you :mdr:

Is that the PCB you found off batteryjunction?

No.

What you're looking at is, the tops of 30 cells taken out of the plastic housings on cell phone batteries.

Each one has it's own pcb.

Ah, I see!
Thought you soldered each PCB on by yourself... That would've sucked.

Neat idea though, would hate to see something conductive fall inbetween those two leads- positive and negative... That sucker would POP!

There are several safetys built into this style pcb.

Overcharge Protection
Overdischarge Protection
Short Circuit Protection

A PCB works like a switch. If it doesn't like what it sees, it just switches off and breaks the connection. :yes:

very cool

Colorful looking blaster...

Regards diodes, since the battery & charge circuit will be in parallel to the radio essentially, I figure a single diode in series between the battery and charger 9a long the ground wire ) will prevent current flowing back from the batt to the charger, but allow it to flow from charger to batt. Wouldn't like to guess at the rating required, thats a job for BG.

Now all you need is a broom and a street corner.

http://www.youtube.com/watch?v=BVrWDPi12zE

The Boombox came in today, and it's great. The thing really jams.

So...........on with the Battery Pack building.

We now know our compartment size and how many will fit.

We are using 42 cell phone batteries to make the big one.

See that little jewel in there?

http://i160.photobucket.com/albums/t...m/DSC08013.jpg

Complete with their own pcb's, stacks of 7 are arranged in preparation to make parallel cells.

http://i160.photobucket.com/albums/t...m/DSC08017.jpg

Then shrink is applied to the lower most portion of the stacks to hold everything while soldering.

Six of these stacks will be used. This fit the size shrink I had on hand.

http://i160.photobucket.com/albums/t...m/DSC08018.jpg

I did some testing. A single cell discharged to 3.0volts, took back 950mah. This makes the large 3S pack's capacity, about 13,300mah.

When the box is really jamming, the power analyzer reports amp spikes around 1.3 amps. This will make for about 10 hours of extra loud tunes per charge! :yipi:

Much longer tunes at lower volume levels. As a moderate volume only pulls .5 amps. Moderate volume runtimes will be around 30 hours or so.

I'll report back as progress continues.

Not sure how many of those batteries you have left, but if I decide to get one of these Ghetto Blasters, would you be willing to sell some?