# 9 Volt Battery Problem

#### Night_Bird01

Joined Feb 16, 2019
1
So, I have a small Arduino project that simply changes the color of an RGB led diode. The project itself works fine, however, if the battery is left off for more than 30 minutes it completely stops the Arduino from turning on and the current stops moving. I was wondering if anyone has a solution or if someone else has had this problem as well.

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Joined Jan 15, 2015
5,148
What is that at the bottom of the picture which is across the battery and Arduino power in? If that is a switch it looks to be shorting your battery.

The Arduino external Input Voltage (recommended): 7-12 V for the pictured battery this is the data sheet. So what is the Arduino and LED load total, approximately?

Ron

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#### Audioguru

Joined Dec 20, 2007
11,251
The 9V alkaline battery is little so it does not produce much current for a certain length of time. Also maybe the battery was not brand new?
It can produce 100mA for about 3 hours when its voltage has dropped to about 5.5V.

A larger battery made with six AA alkaline cells can produce 9V at 100mA for about 20 hours when its voltage has dropped to 5.5V.

An even larger battery made with D alkaline cells can last longer.

Where is the battery current going? Into the LED that is too bright? Its current is less and the battery will last longer if the LED is dimmed.

#### Audioguru

Joined Dec 20, 2007
11,251
What is "If the battery is left off"? Is the battery disconnected and is turned off? Is the battery turned on? Is the battery shorted?

#### WBahn

Joined Mar 31, 2012
25,318
Since, in your picture, the battery is ALWAYS connected to the Arduino input jack, we can pretty much only assume that you are turning the battery "off" by closing a switch and shorting the battery out. I'm guessing that the "fix" you have been using is to replace the battery and then are discovering that the next time you turn it "off" for any length of time you have to repeat this process.

Not only are you draining perfectly good batteries, you are creating a potential fire hazard as you will likely find that that battery is getting pretty warm after you turn it "off".

Instead, put the switch in series with one of the battery leads (usually the positive on) so that when you switch the battery "on" the switch closes the path between the positive terminal of the battery and the Arduino plug but when it is "off" that path is simply broken. The other wire then just goes directly from the battery to the Arduino plug.

#### WBahn

Joined Mar 31, 2012
25,318
Also, you want to insulate exposed wire joints like you've got. It would take very little motion of any of your parts to short those wires together. Use electrical tape or heatshrink.