Answered upgrade output from 12v to 24v?

? you bought a 24v power supply?
The electronics run on 12v so that has to be stepped down.
The bed heater can be 24v but you need a 12v relay from the RAMPS output to control it...
Hotend heater cores are 12v (stock).

Seriously if you want to convert to 24v, buy 24v boards and convert the entire electronics (boards and heaters too).

SmoothieBoard
or
Shanhai® Gt2560
or
SainSmart 2-in-1

Just to name a few that are 24v capable, search around and see what you find. The older Fastbot BBP board was 24v capable (and also was a 32-bit board) but the company has gone under... you might find some available for resale.

Others will have more suggestions, but you need to be more clear what you are trying to do

 

You can't bump the output of the RAMPS to 24v, it only outputs 12v. If you put a 24v heater core on it then that heater core will only work half as good as it was intended to It will operate at effectively half-power.

The only way to use a 24v heater (bed or extruder) with the stock electronics would be to put a relay on the output from the RAMPS that closes when you give it 12v and then have the contacts on that releay turn the 24v from a different power supply on and off to the heater as needed.

That will work, but it is a lot of extra work and effort to just move up to 24v. Better and easier to swap the electronics and power supply to all work at 24v.

 

or live with the 12v stuff you have installed already

The advantage to 24v is having things heat up faster...

 

Not that simple. Whatever goes in series has to source and sink all of the current for the heater too ☺

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