Stepping up to 24V


Henk Aling
 

I ordered a 12 to 24 V DCDC 72 W step up converter for my Wemos/CNCv3 with TMC2130 stepper drivers and 17HM15-0904S stepper motors.  I expect that the torque will step up faster than when I use 12 V, which will help my autoguiding, and that the heat dissipation will be less. 

My plan is to plug the 24 V into the CNCv3 external power clamps and lead the 12 V to the Wemos separately (currently both are connected together to 12V).  My understanding is that the 24V only gets to the external voltage pins of the TMC2130, and that the TMC2130 and the motors can workon 24V.

If I make a fatal mistake by doing it this way please let me know, if you have experience with such a system that would be interesting too.  Thanks!


Robert Benward
 

Henk,
Get a schematic or specifications to make sure you can plug in 24V.  I am using a MaxESP and they come with switching buck regulators.  They drop the voltage down to 5V and take 35V or more on the input.  There may not be any need to provide a separate supply to the Wemos. 

Also, you may wish to change the connector on your set up.  It's dangerous to use 24V on the standard 5.5x2.1mm plug and socket.  Too many astronomy things run on 12V max and use the same plug.  In the dark when you're fumbling around is not the time to find out you inserted the wrong plug into a 12V socket.

Bob


George Cushing
 

There are 2 voltage regulators on the D1 R32. The first is a MP1482 with 5V output, max input 18V. The second is a NCP1117 3.3V output max input 20V. so you are wise to keep the power in at 12V.

The screw terminal on the CNC3 is rated to 35V. To get power for the shield I've been tapping the mount lugs of the D1 R32's power jack.


Heating the lugs and giving the board a tap will clear the hole in them for connecting your leads. The leads can power your step up buck. This model seems to fit your needs and has screw terminals in and out.


 

I would try to do this by desoldering VIN pin from Wemos and supplying Wemos with 5V from stepdown converter directly to +5V pin. This way you override MP1482 and then you can supply Shield with as much voltage as electrolytes and stepsticks can handle. Don't forget thwt input for buck converter should have fuse. 

In fact, I did same thing but with RAMPS and Mega. After tests, I decided to stay on 12V, because in _QUIET mode, my drivers and motor combinations works just fine so I saw no reason to use 24V. Everything is cool&quiet with plenty of torque.on regulated PSU or lead-acid car battery.


kevin_kevin_kevin@...
 

I and some others have had issues on some R32 boards where  the MP1482 only producing about 4.3 volts without the USB lead connected as well which leads to the 3.3v regulator only outputting about 2.7v and the bluetooth not working properly. I havn't had time to chase it down yet and as my USB is connected i dont need anyextra power on the R32 board and just power the CNC3 board directly. It works ok but i suppose there could be issues with the order power is supplied but i have not yet had any problems with it.

have a look at the Nov4 thread

Unable to connect Bluetooth from Wemos D1 R32


Henk Aling
 

On Tue, Nov 23, 2021 at 01:28 PM, George Cushing wrote:
There are 2 voltage regulators on the D1 R32. The first is a MP1482 with 5V output, max input 18V. The second is a NCP1117 3.3V output max input 20V. so you are wise to keep the power in at 12V.

The screw terminal on the CNC3 is rated to 35V. To get power for the shield I've been tapping the mount lugs of the D1 R32's power jack.

Heating the lugs and giving the board a tap will clear the hole in them for connecting your leads. The leads can power your step up buck. This model seems to fit your needs and has screw terminals in and out.
Thanks George.  Most of the Wemos D1 R32 searches mention 5-12V input voltage so I will just stick with that and apply the 24V only to the CNCv3 input connector.  That should go just to the external inputs of the TMC2130s and nowhere else as far as I know.   I will receive the step-up converter next week. 

Thanks everyone for confirming that this should work (at least no one told me it will fry anything - I buy 2 of each usually so one failure is OK).


George Cushing
 

Think that's smart. Batteries will give a circuit all the amperage they contain if asked. That's why you can weld things together with them. I've been reading up on the ESP32 and it's designed to need very little current. Certainly, the 1A available from the NCP1117 is enough. The only reason the D1 R32 is powered by 12V, is that most people don't have 3V3 power supplies and it's handy to have the 5V for shield logic.