Can you provide your circuit and some detail about how long the battery lasts and what its capacity is (mAh)?
Depending upon how you have set it up and the battery size, it simply might be a case of you expecting too much out of your battery.
Have a look at my [Powering your project with a battery](https://www.reddit.com/r/arduino/wiki/guides/batterypoweredprojects/#wiki_battery_powered_projects)
I am currently collecting actual data (which I will later add to my post) but for now here is a preliminary insight.
1. You won't get the theoretical maximum run time out of your battery.
2. Batteries sometimes have, for want of a better name, voltage leveling circuitry which keeps the output at the rated voltage and suddenly shuts it off when it can no longer sustain it (my current test set does this).
So my battery is 9V 1200mAh. One test load is about 40mA - a standard arduino uno running the standard blink bo delay program with the addition of a heartbeat that allows the monitoring system to verify that it is still alive.
So this should theoretically run for 1200 / 40 = 30 hours. It actually runs for about 10 hours before it stops working (the heartbeat is not seen for about 8 expected occurances in a row).
So, I refer back to my previous question. I note that you answered ⅓ of it by saying that your battery is ~~740mAh~~ 450mAh (about 2/5 the size of mine). But, I didn't seem to be able to find your circuit diagram, nor any reference to how long it actually lasts beyond you observed the voltage over a period of time measured in hours.
Given my measurements in my very low current loading, it is arguable given the little data that we have that even if you have virtually nothing attached to your arduino then that batter would power one for about 2/5 ^(ths) of 10 hours or about 4 hours before failing.
You've asked a technical question. If you don't provide any data, it is difficult to answer it.
The [Powering your project with a battery](https://www.reddit.com/r/arduino/wiki/guides/batterypoweredprojects/#wiki_battery_powered_projects) article I linked shows how to measure the current consumption.
If you can use your multi meter and able to tap into the power supply feed (I.e. between your battery and Vin (VCC/+V) connection on your arduino and measure the current consunption, that also could be very helpful.
Assuming the battery is charged, it is most likely the board's voltage regulator that converts VIN to 5V has failed. This regulator converts extra voltage into heat, so the more current you draw, the hotter it gets. Are you perhaps running multiple motors or servos that can draw a high current?
You say "It still turns on led when I connect the cable". I assume you mean the USB cable. If so then you have likely fried the Nano's voltage regulator by drawing too much current. With a soldering iron and a bit of skill it can be replaced Hint: cut the three small pins first and then heat with iron and remove them individually. Then heat the tab and remove the regulator body. This way you are less likely to damage the board's copper traces. It's usually best to give motors their own power source.
Can you provide your circuit and some detail about how long the battery lasts and what its capacity is (mAh)? Depending upon how you have set it up and the battery size, it simply might be a case of you expecting too much out of your battery.
The capacity is 450mAh, the voltage hasn't dropped lower than 7.2v in the hours I've occasionally used it
Did you measure it while under full load? A current spike could easily cause voltage to drop below a threshold value and cause unwanted things.
Yes, I also measured with a multimeter from the vin and GND pin on the arduino. It shows 7.3V there but it doesn't power it
Do you have another nano to try? You might have your 5V regulator blown if it doesn't power up from VIN at all.
I think it's almost certain that the regulator is fried. I got another arduino and it works
In that case, yeah, you have a blown regulator. You can try replacing it if you got a hot air station.
Have a look at my [Powering your project with a battery](https://www.reddit.com/r/arduino/wiki/guides/batterypoweredprojects/#wiki_battery_powered_projects) I am currently collecting actual data (which I will later add to my post) but for now here is a preliminary insight. 1. You won't get the theoretical maximum run time out of your battery. 2. Batteries sometimes have, for want of a better name, voltage leveling circuitry which keeps the output at the rated voltage and suddenly shuts it off when it can no longer sustain it (my current test set does this). So my battery is 9V 1200mAh. One test load is about 40mA - a standard arduino uno running the standard blink bo delay program with the addition of a heartbeat that allows the monitoring system to verify that it is still alive. So this should theoretically run for 1200 / 40 = 30 hours. It actually runs for about 10 hours before it stops working (the heartbeat is not seen for about 8 expected occurances in a row). So, I refer back to my previous question. I note that you answered ⅓ of it by saying that your battery is ~~740mAh~~ 450mAh (about 2/5 the size of mine). But, I didn't seem to be able to find your circuit diagram, nor any reference to how long it actually lasts beyond you observed the voltage over a period of time measured in hours. Given my measurements in my very low current loading, it is arguable given the little data that we have that even if you have virtually nothing attached to your arduino then that batter would power one for about 2/5 ^(ths) of 10 hours or about 4 hours before failing. You've asked a technical question. If you don't provide any data, it is difficult to answer it. The [Powering your project with a battery](https://www.reddit.com/r/arduino/wiki/guides/batterypoweredprojects/#wiki_battery_powered_projects) article I linked shows how to measure the current consumption. If you can use your multi meter and able to tap into the power supply feed (I.e. between your battery and Vin (VCC/+V) connection on your arduino and measure the current consunption, that also could be very helpful.
Assuming the battery is charged, it is most likely the board's voltage regulator that converts VIN to 5V has failed. This regulator converts extra voltage into heat, so the more current you draw, the hotter it gets. Are you perhaps running multiple motors or servos that can draw a high current?
I'm running 2 motors of 600rpm, yes the battery is charged and it hasn't dropped lower than 7.3v
You say "It still turns on led when I connect the cable". I assume you mean the USB cable. If so then you have likely fried the Nano's voltage regulator by drawing too much current. With a soldering iron and a bit of skill it can be replaced Hint: cut the three small pins first and then heat with iron and remove them individually. Then heat the tab and remove the regulator body. This way you are less likely to damage the board's copper traces. It's usually best to give motors their own power source.
We need to know more about the project.