12v PSU for hot end heater only

[Rushmere3D]

So I happen to have an E3D Revo Micro that I'd like to use with my toolchanger. But it's a 12v version and the TC is 24v, I have a Duet3 so was thinking could I use another out put for the SSR controlled bed and feed 12v into the bed in and the Revo heater from out0? So that I can fit everything on the back of TC, what's the smallest PSU I can get away with? 60W?

Thanks.

[Phaedrux]

What is the wattage of the revo heater? 40w? I'd say 60w should be fine if only the heater cartridge is powered.

[Rushmere3D]

@phaedrux

Yep, it's a 40w heater. So in terms of using say Out3 (hot end 3) for controlling the SSR bed, is it just a matter of changing the config to reflect that?

[Phaedrux]

Indeed.

For example

M143 H0 S120                                 ; set temperature limit for heater 0 to 120C
M308 S1 P"temp3" Y"thermistor" T100000 B4138 ; configure sensor 1 as thermistor on pin temp3
M950 H1 C"out3" T1                           ; create nozzle heater output on out3 and map it to sensor 1
M307 H1 B0 S1.00                             ; disable bang-bang mode for heater  and set PWM limit
M143 H1 S280                                 ; set temperature limit for heater 1 to 280C

[Rushmere3D]

@phaedrux

Perfect thanks, one more question, haha.

Most PSUs we see in printers are those led ones right so I'm looking for the same thing in this situation correct? I've seen 12v 60w 5A.

[Phaedrux]

Maybe something like this?>

https://www.digikey.ca/en/products/detail/mean-well-usa-inc/LRS-100-12/7705004

[achrn]

If you have 24V available, how about a 24V to 12V POL convertor? That will be smaller and lighter than a mains PSU.

https://www.digikey.co.uk/en/product-highlight/t/tdk-lambda/i3a-series-non-isolated-dc-dc-converters is 23.4mm x 19.1mm x 9.6mm and weight 8g and will give you 100W.

I'm not sure how much it will like a rapid PWM load, and you'd need a better datasheet than I can find at that particular link, but it (or similar) looks worth examining?