Welcome to the SeeMeCNC Community

I'm trying to get my Onyx plate up to 110 degrees Celius, right now it takes half an hour just to get to 90 degrees.
Is that normal?

grimmindustries wrote:I'm trying to get my Onyx plate up to 110 degrees Celius, right now it takes half an hour just to get to 90 degrees.
Is that normal?

It could take that long. Try covering the bed with a towel while it is heating, this helps to insulate the bed and allow it to get to temperature
more quickly.

There are a couple of things that might reduce the time:

Get a hot pad from the kitchen and lay it on the bed.
Aluminum foil/hot pad.
and Other things to keep the heat on the bed....

And if you search this forum, you'll find that some folks are using separate power supplies (and relays) to heat their bed.

(Eaglesoar and I seem to post at the same time...frequently! LOL)

Thanks for the advice everyone, I am considering the additional power supply.

Re-post-
This cake pan trick has been working pretty well. http://forum.seemecnc.com/viewtopic.php ... 572#p26572
I'm not running an aluminum heat dissapator or 24V, but I think restricting the amount of ambient air you have to heat up really helps.

JohnStack wrote:There are a couple of things that might reduce the time:

Get a hot pad from the kitchen and lay it on the bed.
Aluminum foil/hot pad.
and Other things to keep the heat on the bed....

And if you search this forum, you'll find that some folks are using separate power supplies (and relays) to heat their bed.

I do not recommend standard relays. We have been using 24V 30A power supplies from Ebay that connects to the output of a solid state relay (DC-DC)
which then feeds the Onyx. The input to the SSR comes from the Rambo HeatBed Output.
Standard Relays produce huge amounts of EMF when the coil energizes and de-energizes. Not something I would want in my machine.

Eaglezsoar wrote: I do not recommend standard relays. We have been using 24V 30A power supplies from Ebay that connects to the output of a solid state relay (DC-DC)
which then feeds the Onyx. The input to the SSR comes from the Rambo HeatBed Output.
Standard Relays produce huge amounts of EMF when the coil energizes and de-energizes. Not something I would want in my machine.

Not only that, but the PWM coming out of the RAMBo will beat the relay to death. The buzzing may also drive you nuts.

g.

I got an additional power supply but I'm not sure I'm going to wire it correctly, does anyone have a wiring diagram?

grimmindustries wrote:I got an additional power supply but I'm not sure I'm going to wire it correctly, does anyone have a wiring diagram?

grimmindustries wrote:I got an additional power supply but I'm not sure I'm going to wire it correctly, does anyone have a wiring diagram?

having an additional power supply isn't going to do much unless its an 18- 24v supply. Just adding another 12v supply (assuming your adding another 12v supply) will net you nothing because its still 12volts. You need more voltage to get more current going through your onyx in order for it to heat up faster.

I run mine with a dedicated 24v power supply and ssr. heats up to over 100c around.. 5min. http://forum.seemecnc.com/viewtopic.php ... =24v#p7627

as far as the wiring goes here's is an example using an additional 24v power supply just for the heated bed.. (the 12volt stock power supply is still used but not for heated bed power) This shows a ramps board but the idea is the same......you use the output for your heated bed on the rambo board to control your solid state relay. The power for the ssr is strictly through your dedicated source to your heat bed.

cambo3d wrote:

grimmindustries wrote:I got an additional power supply but I'm not sure I'm going to wire it correctly, does anyone have a wiring diagram?

having an additional power supply isn't going to do much unless its an 18- 24v supply. Just adding another 12v supply (assuming your adding another 12v supply) will net you nothing because its still 12volts. You need more voltage to get more current going through your onyx in order for it to heat up faster.

I run mine with a dedicated 24v power supply and ssr. heats up to over 100c around.. 5min. http://forum.seemecnc.com/viewtopic.php ... =24v#p7627

Thanks, I did get a 24v power supply and when I wired it directly to the Onyx it heated up super quick but then it didn't stop heating up. Do I just add the power supply inline with the existing power supply?

I see what I did wrong. I connected the new power supply through output instead of input.
The new 24v power supply is great, it didn't even take 5 minutes for the Onyx bed to get to 100 degrees C.

Can you provide some sort of model # or supply house you got that 24v power from?

Also, you brought that through the Rambo without the SS relay, right? That was my thinking to do as well. The Rambo is different that the picture from Eagle, as there is a 15a car fuse in the upper right corner. I had a suspicion that the fuse could handle the 24v supply. Really it's the current that would cause it to blow. And with 24vdc and a fixed resistance value from the plate, the total current would go DOWN.

gajtguy wrote:Can you provide some sort of model # or supply house you got that 24v power from?

Also, you brought that through the Rambo without the SS relay, right? That was my thinking to do as well. The Rambo is different that the picture from Eagle, as there is a 15a car fuse in the upper right corner. I had a suspicion that the fuse could handle the 24v supply. Really it's the current that would cause it to blow. And with 24vdc and a fixed resistance value from the plate, the total current would go DOWN.

Ohms law says that current = voltage / resistance.

If the voltage is 12V and the resistance of the bed is 2 ohms the total current is 6 amps.

If the voltage is 24V and the resistance of the bed is 2 ohms the total current is 12 amps. I don't know how you say the current would go down.

In actual practice, the current to the Onyx with 24V is approximately 17 amps, if you plan on using the Rambo only you would need to increase the fuse value to 20 amps.

I use the DC-DC SSR because I do not want to run that much current through the traces of the Onyx.

The power supply that most of us used is this one: http://www.ebay.com/itm/Meanwell-Power- ... 3f35668a64

Also, in-rush current to the Onyx can be higher than the 17 amp typical value (I think 19 was the reported peak at 24V, which is why some adjust the voltage down to ~19-20v on those supplies). Fuses (unless slow-blow which is NOT what the Rambo uses) care very little if it is just an in-rush or not.

Eaglezsoar wrote:Ohms law says that current = voltage / resistance.

If the voltage is 12V and the resistance of the bed is 2 ohms the total current is 6 amps.

If the voltage is 24V and the resistance of the bed is 2 ohms the total current is 12 amps. I don't know how you say the current would go down.

My apologies. I messed up on that Ohm law thing big time.

gajtguy wrote:

Eaglezsoar wrote:Ohms law says that current = voltage / resistance.

If the voltage is 12V and the resistance of the bed is 2 ohms the total current is 6 amps.

If the voltage is 24V and the resistance of the bed is 2 ohms the total current is 12 amps. I don't know how you say the current would go down.

My apologies. I messed up on that Ohm law thing big time.

We all make mistakes, no need to apologize.

I've used my wife's hair drier.

Hay guys, have a stupid question.
I'm having a hard time finding a affordable SSR and power supply to switch to 24v for the bed. Only dc-dc SSR's I can find that are rated for the amps are over $100. I can find tones that are dc-ac and affordable.so question, can you use AC voltage on the onyx bed if it is stepped down from 110 to 24v. I can easily get 24v transformer.

RichardMac wrote:Hay guys, have a stupid question.
I'm having a hard time finding a affordable SSR and power supply to switch to 24v for the bed. Only dc-dc SSR's I can find that are rated for the amps are over $100. I can find tones that are dc-ac and affordable.so question, can you use AC voltage on the onyx bed if it is stepped down from 110 to 24v. I can easily get 24v transformer.

Most of us used these:
http://www.ebay.com/itm/Meanwell-Power- ... 3f35668a64

http://www.ebay.com/itm/1pcs-Solid-Stat ... 2a3b6a9c05

And a heat sink for the SSR from Ebay or Amazon

AC would most likely work to heat the heatbed but it also generates EMF at 60 Hertz and harmonics which could very well interfere with the rest of the
electronics. It would also require external control of the temperature because the Rambo is not setup to work with an AC signal.
Do-able Yes....... Recommended NO.

Before spending all that money on a 24V power supply and an SSR, have you tried adding another pair of 18ga wires from the Onyx Rev3 to the RAMBo yet?

g.

Here is the power supply I purchased.
http://www.amazon.com/dp/B006QSOF60/ref ... 25410_item

grimmindustries wrote:Here is the power supply I purchased.
http://www.amazon.com/dp/B006QSOF60/ref ... 25410_item

That one is slightly underpowered because the Onyx will draw approximately 17 amps at intitial warmup but it should be fine
especially compared to the original 12 Volts. After the initial high current draw the Onyx will stabilize at current levels far less
than 17 amps once the PID takes control of the current supplied to the Onyx. There should be a 20 amp fuse on the output of
the power supply you purchased. The Onyx is going to try to draw more than the 15 Amps the supply can handle and it is possible
that for a short duration the supply can push more than 15 amps. I hope I am making some sense.