Battery question

[jmorrone]

Can someone tell me does a battery drain just from being in its holder?

I have a typical battery box from radio shack. It holds two AAA batteries. I have that hooked to a pushbutton switch and then to some leds.

The circuit works fine, but I noticed after leaving it off for a week I came back to try and turn it on and the batteries were close to dead. Is there a way to prevent this or do I just need to remove the batteries?

 

[shrtrnd]

Were the batteries old and weak to begin with?
SOUNDS like circuit is disconnected with pushbutton switch, but you really need
to take a look at your circuit. Is there some other current path that is allowing the circuit
to discharge when the switch is not closed?
Just things to look at.
(I've gotten old batteries before, 'new' from the store)
One other thing to consider, what is the current drain of your circuit itself when it's working.
Is the current draw from the batteries, more than should be, to power your circuit?

 

[daddles]

I'd add to shrtrnd's post that you should measure the current draw with an ammeter in both the on and off state. One measurement worth 1000 speculations...

BTW, if you have some thin double-sided PC board, you can make a simple adapter to help measure the current. Cut out a tab of the board narrow enough to slip between one of the batteries and its terminal. Then solder leads to both sides of the board and insert them in your ammeter. Note your ammeter may affect the circuit's operation.

 

[jmorrone]

My circuit looks fine. I did notice one thing, I was soldering some connectors together on the other end far away from the battery however I noticed when I was finished the batteries were very hot.

I figured conduction from the solder travelled up. I let them cool down and measured the voltage with a volt meter and they seemed ok. .They died shortly after.

I wasn't sure if this could have effected it as I see people solder wires directly to batteries. I never do that because I worry about them exploding, but could this have cause it?

 

[jmorrone]

I'd add to shrtrnd's post that you should measure the current draw with an ammeter in both the on and off state. One measurement worth 1000 speculations...

BTW, if you have some thin double-sided PC board, you can make a simple adapter to help measure the current. Cut out a tab of the board narrow enough to slip between one of the batteries and its terminal. Then solder leads to both sides of the board and insert them in your ammeter. Note your ammeter may affect the circuit's operation.

I do not get any draw when it is off thats why I was confused.

 

[BobK]

My circuit looks fine. I did notice one thing, I was soldering some connectors together on the other end far away from the battery however I noticed when I was finished the batteries were very hot.

I figured conduction from the solder travelled up. I let them cool down and measured the voltage with a volt meter and they seemed ok. .They died shortly after.

I wasn't sure if this could have effected it as I see people solder wires directly to batteries. I never do that because I worry about them exploding, but could this have cause it?

More likely, the batteries were shorted.

Bob

 

[davenn]

My circuit looks fine. I did notice one thing, I was soldering some connectors together on the other end far away from the battery however I noticed when I was finished the batteries were very hot.

I figured conduction from the solder travelled up. I let them cool down and measured the voltage with a volt meter and they seemed ok. .They died shortly after.

I wasn't sure if this could have effected it as I see people solder wires directly to batteries. I never do that because I worry about them exploding, but could this have cause it?

yup you shorted out the batteries and flattened them so there obviously must be a cct wiring fault there somewhere.

Dave

 

[poor mystic]

Sounds like a bad circuit fault in your workshop jmorrone. Hope it's not affecting that wireless comms system you just got going.

You can more-or-less successfully solder wires onto a dry cell with a big, hot iron, but surely it must stuff the battery chemistry up.

PS
Maybe you'll start developing some notions of good practice, like removing batteries before soldering about their terminals!