user37853: I am a newbie and have followed a tutorial to build a battery level indicator as below 

Please suggest any changes I'll need to make to make the circuit useful with a 48V battery as the above circuit is tested with a 12V one. 
Thank You.

user1576: To get a smoother switch from one level to another you could introduce another resistor and use analogWrite() to dim one LED and make next brighter.
Ref.: https://www.arduino.cc/en/Tutorial/PWM


user10794: You have a voltage divider there, which would give (if the pre-set pot was set to the maximum):
Vout = (Vin * R2) / (R1 + R2)
Vout = (12 * 10000) / (100000 + 10000)
Vout = 1.09

Thus a 12V battery would present 1.09V at the analog input. 
This same wiring would seem to be in range for a 48V battery:
Vout = (48 * 10000) / (100000 + 10000)
Vout = 4.36

Since the analog input can handle up to 5V, then that should be OK. However I would test the voltage divider output first with a multimeter to make sure it doesn't exceed 5V - before connecting it to the Arduino.

You would probably need to change the code to test for different ranges of input voltages, other than what is used for the 12V battery.

37853: <p>I am a newbie and have followed a tutorial to build a battery level indicator as below 
<a href="https://i.stack.imgur.com/dJLeR.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/dJLeR.jpg" alt="the basic design "></a></p>

<p>Please suggest any changes I'll need to make to make the circuit useful with a 48V battery as the above circuit is tested with a 12V one. 
Thank You.</p>
 1576: <p>To get a smoother switch from one level to another you could introduce another resistor and use analogWrite() to dim one LED and make next brighter.</p>

<p>Ref.: <a href="https://www.arduino.cc/en/Tutorial/PWM" rel="nofollow noreferrer">https://www.arduino.cc/en/Tutorial/PWM</a></p>

<p><a href="https://i.stack.imgur.com/v5ES0.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/v5ES0.jpg" alt="enter image description here"></a></p>
 10794: <p>You have a voltage divider there, which would give (if the pre-set pot was set to the maximum):</p>

<pre><code>Vout = (Vin * R2) / (R1 + R2)
Vout = (12 * 10000) / (100000 + 10000)
Vout = 1.09
</code></pre>

<p>Thus a 12V battery would present 1.09V at the analog input. </p>

<p>This same wiring would seem to be in range for a 48V battery:</p>

<pre><code>Vout = (48 * 10000) / (100000 + 10000)
Vout = 4.36
</code></pre>

<p>Since the analog input can handle up to 5V, then that should be OK. However I would test the voltage divider output first with a multimeter to make sure it doesn't exceed 5V - before connecting it to the Arduino.</p>

<hr>

<p>You would probably need to change the code to test for different ranges of input voltages, other than what is used for the 12V battery.</p>
