9 volt battery getting hot
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bruce53176
- Posts: 18
- Joined: Wed Sep 23, 2009 11:30 pm
9 volt battery getting hot
I'm testing a circuit with 7 LEDs in paralell. 5 red LEDs a green and a yellow. I have the yellow, green and a red together with a 1ohm resistor then I have another three red together with another 1ohm resistor then one red alone with a 330 ohm resistor. After having the circuit on for only a short while the 9 volt battery that I'm using is very hot to the touch. My first thought is that something is drawing too much current. Should I use bigger resistors or am I missing something within the circuit. Thank you for your help.
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paraclete1
- Posts: 194
- Joined: Thu Sep 09, 2004 8:44 am
- Location: Siloam Springs Ark
Almost sounds like the battery has a direct short somewhere. Had a dogtag chain in my pocket once with a 9V and it shorted across the terminal. Didn't notice it until my leg started getting hot.
Do the lights work alright?
Another possibility might be it's trying to provide to much power at once. Never experience anything like that, but might be worth looking into. You might try reducing the number of LEDs to see how it does with one or two, then add from there.
What about the LEDs and resistor, any heat there?
And it's been a while since I tried any real electronics, but 10ohms sound a little low. But someone more qualified should address that.
Can you draw a diagram of the circuit so we can see how you have each component laid out?
Do the lights work alright?
Another possibility might be it's trying to provide to much power at once. Never experience anything like that, but might be worth looking into. You might try reducing the number of LEDs to see how it does with one or two, then add from there.
What about the LEDs and resistor, any heat there?
And it's been a while since I tried any real electronics, but 10ohms sound a little low. But someone more qualified should address that.
Can you draw a diagram of the circuit so we can see how you have each component laid out?
Don "Let me buy just one more, then I'll quit... I promise!" Pugh
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amandacaron
- Posts: 15
- Joined: Thu Aug 13, 2009 4:40 pm
Somewhere in your circuit is drawing 9 amps . thats alot of current and will heat up that battery fast.
9volts / 1 ohm = 9 amps
a typical 9volt battery only has a life of 1/2 amphour. your draining that battery in 3-5 minutes.
most LEDS have a safe max draw around 25mili amps. So 9 volts would be around in the 36 ohm area not taking into account the front voltage requirement of the specific LED.
9volts / 1 ohm = 9 amps
a typical 9volt battery only has a life of 1/2 amphour. your draining that battery in 3-5 minutes.
most LEDS have a safe max draw around 25mili amps. So 9 volts would be around in the 36 ohm area not taking into account the front voltage requirement of the specific LED.
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amandacaron
- Posts: 15
- Joined: Thu Aug 13, 2009 4:40 pm
this might helpamandacaron wrote:Somewhere in your circuit is drawing 9 amps . thats alot of current and will heat up that battery fast.
9volts / 1 ohm = 9 amps
A typical 9volt battery only has a life of 1/2 amphour. your draining that battery in 3-5 minutes.
Most LEDS have a safe max draw around 25mili amps. So 9 volts would be around in the 36 ohm area not taking into account the front voltage requirement of the specific LED.
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