Hot batteries

Thread Starter

Cougar22

Joined Apr 1, 2013
15
I am NEW at Electronics and Circuits and I am trying to make a Spaceship Prototype.

Here is the Problem: I have a 2 AAA Battery holder that is getting excessively HOT when the Switch is OFF. When the Switch is ON, all the LED's go on and the batteries do NOT overheat. The problem is when the switch is OFF.

Here is the Circuit;

2 AAA Battery Holder (3V) is connect to the 3A 250VAC Switch.

From the Switch I am completing the Circuit to Six (6) .28ma LED's.

Can someone HELP me with this Problem???
 

GopherT

Joined Nov 23, 2012
8,009
Your switch is connected in parallel. It should be in series. As of now, you are connecting the battery negative to battery positive with just copper wire in between when you turn the switch on - don't do that because the battery gets hot and can pop open and hurt someone.


You cannot just connect black to black and red to red on a switch.
 

Markd77

Joined Sep 7, 2009
2,806
I imagine the switch has three terminals, correct me if I'm wrong.
Connect (+) of the battery to the centre terminal
Connect one of the other terminals to one end of the LEDs and resistors (I hope there are resistors)
Connect the other end of the LEDs to the (-) of the battery
Don't make any other connections.
 

WBahn

Joined Mar 31, 2012
30,088
Could you PLEASE post some kind of a sketch of what you have and how you are making your connections. Saying something like the battery holder is connected to the switch isn't helpful because the battery holder has TWO wires and the switch has at least two terminals. So sketch something. It doesn't have to be fancy -- something in Paint will do. Or hand draw it and scan it. Or take a picture and post that.
 

GopherT

Joined Nov 23, 2012
8,009
Switches on small DC circuits do not have polarity (ignore color).

Red battery wire to one switch lead
Other switch lead to all six resistors (100 ohms each)
Connect each resistor to the anode (+) of an LED
Connect the cathode (-) of all six LEDs to the negative battery lead (black)
 

Thread Starter

Cougar22

Joined Apr 1, 2013
15
So I need RESISTORS in between each LED????

Right NOW I do not have any resistors on the project.

What do Resistors Do???
 

DerStrom8

Joined Feb 20, 2011
2,390
So I need RESISTORS in between each LED????

Right NOW I do not have any resistors on the project.

What do Resistors Do???
Forgive my rudeness, but you're expecting to build a spaceship prototype without the slightest idea of what any of the components are or what they do? How do you think that'll work?

Sorry if this sounds mean, I'm not intending it that way. I just can't really wrap my mind around it :rolleyes:
 

Thread Starter

Cougar22

Joined Apr 1, 2013
15
Its OK I am from New Jersey and don't mind your Rudeness.

This is a FUN project so I am learning as I go and ask questions as problems arise.

I have learned alot already at Radio Shack, so I am almost there.

I just have to get this HOT BATTERY Corrected.
 

WBahn

Joined Mar 31, 2012
30,088
What LEDs do you have? Do you have a part number? You've said they are each 0.28mA (seems awfully low current, but then LEDs have come a long way since I last tinkered with them), but what is the forward voltage?

What kind of switch do you have? Does it have just two terminals or three (I'm guessing three because you managed to short the battery pack when it was off).

Could you PLEASE post some kind of drawing!
 

DerStrom8

Joined Feb 20, 2011
2,390
What LEDs do you have? Do you have a part number? You've said they are each 0.28mA (seems awfully low current, but then LEDs have come a long way since I last tinkered with them), but what is the forward voltage?

What kind of switch do you have? Does it have just two terminals or three (I'm guessing three because you managed to short the battery pack when it was off).

Could you PLEASE post some kind of drawing!
No LEDs run on 0.28mA. 28mA is much more reasonable.
 

Thread Starter

Cougar22

Joined Apr 1, 2013
15
2 AAA Batteries at 1.5V x 2 = 3V

Switch = SPST 3A 250VAC (2 terminals)

LED Forward Voltage = 3.0 - 3.2

LED Current = 24ma

LED = 13,000 MCD


I am trying to put together a DIAGRAM.
 

WBahn

Joined Mar 31, 2012
30,088
24ma is very, very different form the .28ma you mentioned in your first post!

If you try to run six 24ma LEDs from 2 AAA batteries, your batteries aren't going to last long.

How much current you are actually getting is a huge unknown. You are right on the edge of not having enough voltage to get any current to flow at all, even with fresh batteries, and it only takes a small difference to result in a significant current flowing. I would expect your LEDs would not see enough voltage to light up within a half hour or so (if you are using Alkaline batteries).
 

WBahn

Joined Mar 31, 2012
30,088
No LEDs run on 0.28mA. 28mA is much more reasonable.
I just did a quick check and it appears that 2mA is about the lowest. The OP may want to consider those over the 24mA ones he is talking about now.

He may also want to investigate the Joule Thief circuit, but that is probably a bit advanced for him right now -- however it is a pretty simple circuit and he should be able to progress to it fairly quickly.
 

WBahn

Joined Mar 31, 2012
30,088
Depends on what you are doing.

You're saying that all six LEDs come on bright enough right now?

Have you operated them long enough to see how long the batteries can power them?

Do you have access to a multimeter (also known as a VOM or volt-ohm-millammeter)?

How long do you need them to run in your spaceship prototype?
 

Thread Starter

Cougar22

Joined Apr 1, 2013
15
I took pictures and tried to attach them, however I could NOT.

This is a COST SENSITIVE project so I am looking for CHEAP PRODUCTION avenues with High Quality Output.
 
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