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Charger circuit Answered

Hey there,

I'm planning to build a portable stereo speaker box thingy (you know what I mean). In order to power the 2x10W amplifier I want to use a 7.2V 1400mAh battery pack from an old RC car.
As the housing of the box will be sealed I want to implement a mechanism to charge the pack.

For this I wanted to achieve 3 things:
-If the Power-Switch is turned on, the amp should be powered from the power line
-If the Charge-Switch is turned on, the battery pack should be charged
-If both of the switches are turned on, the amp should receive power from the power line while the battery pack is being charged.

I have thought of the following cabling (see attached picture for a schematic)
The blue box is the amplifier, the green box the battery pack and the orange connectors are tamiya connectors (the ones for RC cars)
The first switch (marked in green) is a normal DPST switch which establishes the connection with the power line as well as the connection with the battery
The second switch is a SPDT switch and activates either the connection between the battery and the amp or the connection between the power line and the battery.

Will this work the way I think it will or does this configuration any faults? If the latter, what can I do I have to change?
I'm actually really new to electronics, this if my first project so forgive me, if this setup is actually BS

Cheers and sorry for the long post ^^'


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5 years ago

You are over complicating things. There is no need for a charge selector here. Why do you need to have a switch that enables charging but doesn't power the amp when the power switch already does that for you. There is no need to select wall or battery power either. But you will need to look at your total power needs and the power needed to charge the battery. The wall charger for a cheap RC car battery will only output enough power to charge the battery. It won't support charging and running the amp at the same time. May not offer enough power to power the amp alone anyway. You will want to find a wall adapter that offers the same voltage but has enough current available to support the battery charging and the needs of the amp.