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Need Charger For Amp (v12) Answered

I have an old set of computer speakers that run on 12v dc, I ripped it out and set it up in a radioshack enclosure with 2 9volt batteries connected to a cut-off power cable that fit the main board. (I realize that the 2 9volt batteries are over the 12v mark but its needed because with only the single 9v battery it cannot handle my cardboard box sub-woofer) I want to take 2 rechargeable 9volt batteries and wire them within the case (because unscrewing the case and taking the thing apart sucks to replace batteries) and I have to be able to charge it by pluging it into an outlet. I have moderate soldering skills and work with electrics often although I dont often use high voltages like 120ac wall current :) Can you guys help me out?


I have 2 batteries form this


each one is 6v 600mAh
So together its 12v 1200mAh

This should be perfect for my amp, what is the safest way to set it up though?

I plan to charge each one separately (but have the two ductaped together. How should I wire them? both batteries + to + and - to - then send it to the amp or should I sequence it + to -, etc... ?
Currently its running on 2 9volts in that sequence.

It sucks the batteries wont fit in the case with the amp but oh well I guess.

oh and what should I do to connect them to the amp? I plan to have it as a removable battery, does it even matter what I use? or should I be careful? I mean can I just cut for example a usb cable and make that the connection from the battery to the amp? (remember amp is just the board from some old computer speakers)


you get 6 V 1200 mAH or 12 V 600 mAH with 2 batteries. for 12 V 1200 mAH you need 4 aim to get the needed voltage for the amp. higher may damage the amp. lower makes bad sound (but may solve problems caused by the resistance of he battery - usually does not happen with rechargables) if the batteries are exactly the same it's better imo to charge them together only so they remain perfect matching to each other use any plug that holds the current. i'd not use USB cause you may mess it up with a normal USB device and damage it. i'd use RJ11 (phone plugs) instead idk if safe or not (probably not) and sure its bad to the battery. make a battery pack out of a plastic cable rail

I ended up using a 9v battery clip works for now :)

so its 9 V ? the 9 V battery is the one (and seems to be the only one) thats safe to solder to - its just a box with smaller batteries inside and does not enclose the chemicals directly

get remote control car batteries, they are about $15 charger included
they should power your amp for about 12 hours


keep the battery out of the box, so then you could easily re-charge it

>as for the 12V required for the speakers, the voltage has to be over 7v so that you get moderate sounding speakers

reply to MY post

Thanks I was thinking about that :) Wishing I hadn't tossed out my old one.... The speakers are not 12v I dunno what they are but the amp is 12. anyway thanks again... btw Do they make rc batteries with a little more juice? volt wise I mean

it will work, you don't necesarily need 12v, you can power them by 4 AA, so it WILL work. using that battery is the best way to go, it's cheap yet powerful you could go with a Lead-Acid battery, 6 or 12v, but it's big, heave and a little pricy

yeh, thats why I didn't go for the larger battery. btw I know that I dont need a full 12v for it to work because it ran on a single 9v but I got more base from the 2 9v in series. anyway thanks, I'll get an rc car batt

you can boost bass in electronic ways

1 make about 30 turns of wire on a big bolt (like electro magnet) and connect it in series with the speaker (to the output of the amp)

2 take about 1 uF capacitor and try to connect it between ground and the center entry of the volume control thing. no effect = too small cap. silence = too large

it adds inductance. inductance has higher impedance (like resistance) to higher frequencies and low impedance to bass i did not measure its inductance in uH but 30 turns is about the size to start experimenting with. it also depends on the amp and speaker

if you are going after bass, mount the speakers into a bigger box, then cut a 1" diameter hole

ok guys sorry for so many posts I'm going to wire in series. Now do I need a more powerful charger or will it just take longer?

you need charger for the voltage of 2 batteries (12 V)

if the batteries are identical and identically charged try to connect them in parallel and not series. this sometimes makes magic