installed two heat cartridges

[mpickens]

I have a Rostock MAX V2 that I built last year. I recently installed 2 heat cartridges and it heats up to fast to run the PID calibration. Is there an existing form to either adjust the voltage or set the PID lower to compensate for the extreme rise in heat?

[bubbasnow]

turn your P value down

[Eric]

Or you can remove one of the cartridges. A single 40W cartridge is about the same as the original two-resistor setup.

[teoman]

Or wire them in series.

[teoman]

In the eeprom you can change the max pid value.

No offence, the rambo board is good and fit for purpose but by putting 2 cartridges you are putting a retard in control of a 1000hp sports car. If something goes wrong it will go terribly wrong.

[Mac The Knife]

Don't be surprised if fuse F3 blows, you can put a ten amp fuse in its place. My first hotend I got away with two, 40 watt cartridges and the 5 amp fuse. The second SeeMeCNC hotend I built with two cartridges blew the fuse immediately.

[geneb]

I would suggest you remove the second cartridge. It's totally un-necessary.

g.

[BenTheRighteous]

I remember someone associated with e3d (elmoret?) was talking in a thread here somewhere about replacing the 40w cartridge that ships with e3ds with a 25w cartridge. The takeaway here is that even 40w is excessive and you're running with 80w.

I know symmetry is nice and all but consider what teoman said. If the Rambo locks up and accidentally turns the heat on 100% and leaves it there then you're going to have a serious problem.

[elmoret]

Maxing out a Volcano at 255C uses about 60% PWM on a 25w heater.

80w is overkill and dangerous if the firmware or FET fails.

[teoman]

Just did a calculation and putting them in series will not work.

You are doubling the resistancewhich would halve the current and 1/4 the power.

And i am not sure a 10W combined heater would suffice.

[mpickens]

Thanks for all of the replies! I was told that 2 would be over kill but I was wanting MORE POWER!!! I was unaware that things could go so wrong, and a chance of a failed eeprom sound like I better remove one of the cartridges... just in case. Thanks!

[Polygonhell]

Even a single 40W heater cartridge is way overkill for most purposes. Bear in mind the JHead that was widely used uses a single 6 Ohm resistor as the heater for ~24W of power and will readily melt itself if you set the temperature too high. Now the original SeeMe hot end has a lot of exposed aluminum surface area, and might need a bit more than the JHead, but it should be in the same ballpark.

The "problem" with heater cartridges in general is they don't fail at extreme temperatures and with no control or cooling they will get more than hot enough to glow red hot and start a fire with pretty much any flammable material they happen to be in contact with. They are a better solution because they don't tend to fail, and somewhat worse because that causes it's own set of issues. I really like the fact that E3D has moved to a 25W cartridge.