Voltage/amp change beginners help required

[netenabled]

Hi Guys,

I have brought a bluetooth receiver which I would like to power with my 12v 7000mah battery.

The bluetooth receiver has a rechargeable battery, the only info I have on this is that it is 140mah.

I want to remove the battery that is inside and power off of the 12v battery.

I am assuming that the bluetooth unit is 5v as it can be charged through USB.

How would I step it all down to the appropriate wattage/amps/volt.

I tried using a 12v to 5v car usb adapter but it burnt out the board. I think this is because 7000mah was going through it.

Any help would be greatly appreciated. Is there any more info that you guys would need from me?

I think I just need to use resistors, but I am confused with how to use a calculator to work out what I need.

 

[4pyros]

I have brought a bluetooth receiver

What kind?

power with my 12v 7000mah battery

What kind?

a 12v to 5v car usb adapter

What kind?

Can you get a car adapter for your bluetooth receiver?

Andy

 

[netenabled]

Hi,

The bluetooth adapter is the following:

**broken link removed**

The battery is the following:
**broken link removed**

The Car adapter is
**broken link removed**

I want to remove the chargeable battery from the bluetooth and have it supplied directly from the battery.

 

[netenabled]

Anyone? Able to help me here

 

[MikeMl]

Answer the questions posted above, and you might get some suggestions.

 

[4pyros]

I guess the OP doesn't what to tell us.

 

[4pyros]

I want to remove the chargeable battery from the bluetooth and have it supplied directly from the battery

You may have to leave the battery in the headset. I will look into this later. Andy

 

[Dr_Doggy]

OP just get the "car charger" for your device, leave the original package together

 

[audioguru]

The bluetooth device probably has a single "3.7V" lithium rechargeable battery cell and a built-in charger for it that needs an input of 5V.
If you remove the lithium cell then you also must remove the charger circuit and feed 3.7V to the circuit.

An LM317 adjustable voltage regulator IC circuit can have a 12V input and a 3.7V output but it might get hot and need a heatsink.

 

[4pyros]

I tried using a 12v to 5v car usb adapter but it burnt out the board.

This should have worked. Did you try it in a car or did you hook it up to the battery? Did you have the polarity right?

The dongle may not work with the charge cord pluged in. Have you tryed it?

What are you going to use this with?

FYI- From what I have read these cheep dongles will not last long and are only good for ten feet.

Andy