Building battery back for old Ghettoblaster.

[Williham]

Hey all, I've just got myself an old Sony Fh-7 Ghettoblaster from ebay, its an old mid 80's thing which is meant to be high quality as far as sound goes. Trouble is you used to be able to buy a rechargeable battery pack for the model, however they are now extremely rare, so I've decided to build myself one instead.
I was just wondering if anyone knew a good website to get some decent batteries, as its easy to find aa/d/c batteries, but I was looking for a more all in one solution rather than a mass of aa's... And don't realy know where to look?
Also, as far as a recharging circuit goes would one be difficult to build?
Cheers,
Will

 

[Nordic]

Electric drill battery?

 

[Buckapound]

How many volts?

There are a few of us building boomboxes, either from scratch or gutting old blasters like yours and putting in class D amps and better drivers. From what I've seen, people are using either lead acid gel cells or lithium, most commonly salvaged from old laptop supplies.

The lead acids, while heavy, work very well, and come in a variety of amp-hour sizes, but you're generally limited to 6, 12 and 24 volts as far as chargers go. Actual voltages run a little higher than nominal, also. There are good, computer-controlled chargers that will keep them in a good chemical and electrical state.

Lithiums stack up in 3.7v increments usually, and obviously need to be charged properly to avoid them overheating/exploding.

For either, you might poke around batteries.com and see what suits your needs.

NiMH packs have the problem of low internal resistance, which means they drain out while idle, so you have to keep them topped up.

--Buckapound

 

[neutron7]

if you have the old one there are places (here anyways) who will replace the cells in cordless drill and laptop batteries.

my 10 year old dewalt drill is better than new with more powerful batteries.

one is "the source by circuit city" which bought all the radio shack stores and stopped selling any electronics parts.

 

[Pjotr]

Lithiums stack up in 3.7v increments usually, and obviously need to be charged properly to avoid them overheating/exploding.

My 2 cents:

Stay away from lithium batteries if you don’t fully understand them, especially in high voltage stacks. These are wonderful and powerful batteries but they need a complex battery management system to keep them alive and safe. I.e. they can’t stand any bit of over charge.

Cheers

 

[Williham]

I dont actualy know the voltage yet, as I've just ordered it from ebay and it hasen't arrived.
I haven't actualy got the old battery, the guy selling it never had it.
As weight is no issue for me I'll have a look at some lead acid battery's.
Thanks for the advice!