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Battery packs keeps melting?

Right now i'm trying to build a circuit that goes from a two AA pack to a switch to a potentiometer to a motor but every time I try to add a resistor of any size it always stops working. When I don't add the resistor the battery pack just melts and I have to buy a new one. Does anyone know how I can stop this from happening?

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rickharris3 years ago
If the battery pack is MELTING you have something seriously wrong.

I suspect you have a short circuit in your set up.

Using a resistor (Pot) to try to control motor speed isn't a very good way - the resistor absorbs power and gets hot, often very hot.

You need to either use a lower voltage, take a cell out of your battery pack, or make it so you can switch in different numbers of cells.

What exactly are you trying to do.
robot19 (author)  rickharris3 years ago
Im building a laser project for the laser contest, I have built this before but I dismantled it, this time for some reason It just overheats.
robot19 (author)  robot193 years ago
what is the best way to control motor speed without using a pot, I kinda figured it was either the switch, the pot, or both that was either cutting off the circuit completely or just slowing it down too much causing the batteries to overheat.
Again not that an easy question to answer. - It depends on how good you need the control to be.

A simple way might be to get a variable voltage regulator - This is controlled by your pot and feeds a varying voltage to the motor (make sure the regulator is capable of supplying the required current.)

Pulse width Modulation pwm is the usual way if good speed control is required. You can look this up.

Try to isolate what is causing your circuit to overload the battery pack. PS they normally get quite hot before they melt so perhaps keeping an eye on the temperature might help.

A good photo of your set up might help us as well.
I'd vote for the adjustable regulator here, its not worth the complexity of PWM.
resistor in series ?
caarntedd3 years ago
I think you need a bigger power supply, your load is sucking the batteries to death.
robot19 (author)  caarntedd3 years ago
well the motor says that it's good for 1.5 to 3 volts so i thought anything above 3 was pushing it.
It's not the voltage, it's the current load.
You are burning up power through the pot as well.
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