iPod Speaker Mod. 6v or 9v? Need advice

[natejp]

I want to power an iPod speaker (Altec Lansing inMotion) using an external battery because at full blast, it burns through 4AA batteries in ~15 minutes. This is annoying, because I have to keep changing the batteries, and AA batteries aren't cheap.

The way it came, it uses 4, 1.5v AA batteries, OR a 9v AC adapter (Output 9V 1.6A). I opened the speakers' case up, and the batteries are connected in series for a total of 6v.

Here is my question:
Do I:

1) get a 6v lantern battery and use that to power the device by soldering leads to the battery terminals.

or

2) Make a 9V DC source to plug in the back.

I am also open to other suggestions.

Thanks guys,

Nate

 

[(*steve*)]

Can you tell us if the DC adapter is connected to the same place as the batteries connect to the circuit? There is normally a switch in the socket that disconnects the batteries as the plug is inserted, you might expect to see one wire from the batteries and one from the socket going to the same place on the board (or at least are connected on the board) whilst the other battery lead goes to the socket and a similarly coloured lead goes from the socket to the board.

The neatest approach is to plug your battery in via the socket at the back. It may be possible to use your large lantern battery here.

 

[natejp]

I do not think that the AC adapter is attached in the same way as the batteries. I ended up putting a new jack on the front of the device for a 6V input, and just soldered the jack to the +/- 6V battery terminals inside of the device.

I priced out batteries, and got 8 "D" size duracells for $10, which have more mAh per $ than any lantern battery I could find. 4 D cells connected in series (to get 6v) powered my speakers at full blast for the entire time I needed them to, ~3.5 hours. I used the device again for ~15 min the other day, and they still show no signs of slowing down. I also still have 4 more untouched D cells for later use!

Last year, I think I went through 24AA batteries in 2 hours, and I had to constantly switch them out 4 at a time! This was a definite improvement and huge success.

 

[(*steve*)]

Sounds like the right solution. Often the external power just connects in place of the batteries. If that was not the case for your device, then my next suggestion would have been to do what you indicated.

Did you use a different connector? Just to help prevent any silly mistakes, it would be best to have used a different connector. Also it is best to follow the "centre/tip positive" convention that seems to apply to 90% of these things.

Good job