Power consumption of total electronics and motors

Dan1990 · 18 Mar 2021, 20:47

Good evening,

I performed the calculation to figure out the power consumption of my printer and I am not sure if I am correct.

My PSU at the moment is 24V and 25 A non - name brand. I would like to change it to Meanwell and I wonder what size of PSU will be most suitable for me.

My setup:
Duet 3 HC
5 motors - e3d High Torque Motor - 1.62 A
1 motor - e3d compact but powerful - 1.62 A
Hot end - E3D V6 - 40W heater - 1.6 A
Hotend fan - no data for PC but so I assume is around 0.1A
Blower fan - no-name from Aliexpres - 0.1A

So, the sum of all current is 11.52A. Taking into consideration that the motors are not running on full power, therefore the PC will be lower.

I reckon that the Meanwell 350.4W 24V 14.6A LRS-350-24 will be enough but I will appreciate a second opinion.

Thanks
Dan

droftarts · 18 Mar 2021, 20:54

@Dan1990 No heated bed? That's usually the biggest current draw.

Ian

Dan1990 · 18 Mar 2021, 20:58

@droftarts

The heated bed is powered from the mains.

Phaedrux · 18 Mar 2021, 21:04

That looks ok. When the heated bed is AC powered you can get away with a much smaller PSU. Meanwell has some nice passive units in the 200-300 watt range that work really well.

theruttmeister · 18 Mar 2021, 21:06

More than enough.

Remember that the current values you are using for the motors are peak, for sizing a PSU you want to be using RMS (kinda)

Last time I bothered actually using a meter to check (and I admit it was a very long time ago) a RAMPS based printer with a ~40w heater (hand wound, so the ~ is doing a lot of work), was only drawing 70W at the wall in normal operation.

Over a sample size of over a thousand printers that I am familiar with, 24v 200W Meanwell PSU was never insufficient.

Maybe if you were running a Duet 3HC with big NEMA23's and really driving stuff hard...

IIRC, even tested a 100W PSU... worked just fine. But the price difference was small enough that we kept the 200W.

droftarts · 18 Mar 2021, 22:02

I power my little Delta printer with no heated bed with a laptop PSU; 19V @ 3.42A = 64.98 watts!

Ian

Dan1990 · 19 Mar 2021, 05:55

Thank you for all your replies! Now I am sure Have a good weekend

dc42 · 19 Mar 2021, 07:05

The motors will draw far less current than you are assuming. See https://duet3d.dozuki.com/Wiki/Choosing_the_power_supply. A 5A PSU would likely be sufficient.