Max voltage for RAMPS Hi all, I have been looking at the circuit diagram for RAMPS. Currently I have a Sanguinololu and it is run from a 19V supply. I know that the Mega can accept up to 20V so if I put 19V I am assuming the RAMPS board will send the 19V to the Arudino and pull back the 5V to run on. Am I even close? :) https://reprap.org/forum/read.php?219,114272,114272#msg-114272 Wed, 15 Jul 2026 10:15:24 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?219,114272,848832#msg-848832 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,848832#msg-848832 Gibbedy RAMPS Electronics Sat, 09 Mar 2019 03:02:30 -0500 https://reprap.org/forum/read.php?219,114272,432786#msg-432786 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,432786#msg-432786
Quote
Dust
jbernardis, I think your a bit late, was posted February 09, 2012!!!!!!!

This is what happens when someone resurrects an old thread. I didn't even notice the date ☺]]> jbernardis RAMPS Electronics Sun, 16 Nov 2014 02:53:51 -0500 https://reprap.org/forum/read.php?219,114272,432760#msg-432760 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,432760#msg-432760
from [arduino.cc]
"The board can operate on an external supply of 6 to 20 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts."

If you remove d1 from your ramps and power your mega separately, the ramps itself can have more voltage, depending on a few things.
1) the capacitors, some boards have 16v some have 35v caps, with 16v caps, you should stick to 12v, for 35v caps you go use up to 30v no issue (most use 24v)
2) the polyfuse, the 11amp poly fuse is only rated for 16v. So you must replace that if you use more.]]> Dust RAMPS Electronics Sat, 15 Nov 2014 22:11:28 -0500 https://reprap.org/forum/read.php?219,114272,432757#msg-432757 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,432757#msg-432757 Dust RAMPS Electronics Sat, 15 Nov 2014 22:01:38 -0500 https://reprap.org/forum/read.php?219,114272,432752#msg-432752 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,432752#msg-432752
Quote
Donald King
If the D1 diode is not used, and a computer is not connected to the USB connection on the RAMPS 1.4, can the Arduino Mega be powered using the power connection on the Arduino?

There is no USB connector on the RAMPS - it is on the Arduino. To answer the question, if you do not have the diode in place, you MUST provide separate voltage to the arduino. If it is not via the USB connector, it must be via the on-board barrel connector.]]> jbernardis RAMPS Electronics Sat, 15 Nov 2014 20:51:52 -0500 https://reprap.org/forum/read.php?219,114272,432663#msg-432663 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,432663#msg-432663 Stigern RAMPS Electronics Sat, 15 Nov 2014 14:20:49 -0500 https://reprap.org/forum/read.php?219,114272,118021#msg-118021 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,118021#msg-118021 Donald King RAMPS Electronics Thu, 09 Feb 2012 20:22:54 -0500 https://reprap.org/forum/read.php?219,114272,114353#msg-114353 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,114353#msg-114353
I want to make it totally standalone so I can do without the computer being involved at all (aside from gcode creation). I currently use a bluetooth dongle on my Sanguinololu which works really well, but the Sangi doesn't have enough pins for complete autonomous operation. As I have the powersupply from the Sangi, at 19V, I can supply that for the ramps and I'll regulate it down for the arduino.]]> smartroad RAMPS Electronics Tue, 17 Jan 2012 18:23:16 -0500 https://reprap.org/forum/read.php?219,114272,114351#msg-114351 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,114351#msg-114351 reprap.org] :

D1, D2 - Diodes

These must be placed in the proper orientation. The band on the diode must be turned the same way as the mark on the board.

Definitely solder D2 in. D2, F1, and F2 are shown installed here.

D1 should only be installed if the 5A rail is powered by 12V. It can be omitted and the Arduino will be powered from USB. You will want D1 installed if you add components to print without a PC. To reiterate, D1 MUST be omitted if you are powering the 5A rail by more than 12V.

According to [arduino.cc] the power supply limits for a standard Arduino Mega are as follows:

Operating Voltage 5V
Input Voltage (recommended) 9V
Input Voltage (limits) 7-18V
...
The board can operate on an external supply of 5.5 to 16 volts. If supplied with less than 7V, however, the 5V pin may supply less than five volts and the board may be unstable. If using more than 12V, the voltage regulator may overheat and damage the board. The recommended range is 7 to 12 volts.

My understanding is that the Arduino can safely handle up to 12V incoming power via its own on-board power regulator. If you include D1 it will route the 12V supply from the RAMPS board to power the Arduino, allowing you to run without a USB connection to your PC - e.g. if you install SDRAMPS to print "computer-less", or go one step further to print completely wirelessly as I have set up: [julianh72.blogspot.com]

The only limitation is that you need to limit your power supply to 12V to avoid overloading the Arduino's built-in power regulator. You MIGHT get away with running a 19V power supply to your RAMPS and connecting diode D1, but you would run the risk of over-heating the Arduino's power regulator.

If you omit D1, you don't connect the RAMPS power supply to the Arduino, so you need to have the USB (or an alternative suitable DC power supply) connected to power the Arduino, and the USB will power just the Arduino (and hence the 5V jumpers on the RAMPS), but the steppers and hot end / heated print bed circuits will draw their power from the beefier RAMPS power supply.

Hope this helps!]]> julianh72 RAMPS Electronics Tue, 17 Jan 2012 18:18:12 -0500 https://reprap.org/forum/read.php?219,114272,114298#msg-114298 Re: Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,114298#msg-114298 smartroad RAMPS Electronics Tue, 17 Jan 2012 10:44:47 -0500 https://reprap.org/forum/read.php?219,114272,114272#msg-114272 Max voltage for RAMPS https://reprap.org/forum/read.php?219,114272,114272#msg-114272
I have been looking at the circuit diagram for RAMPS. Currently I have a Sanguinololu and it is run from a 19V supply. I know that the Mega can accept up to 20V so if I put 19V I am assuming the RAMPS board will send the 19V to the Arudino and pull back the 5V to run on.

Am I even close? :)]]> smartroad RAMPS Electronics Tue, 17 Jan 2012 08:01:22 -0500