Stealing power from AMS Plug to switch on extra LEDs

Hi there,
do you know how much power 1 AMS unit is drawing? As I only use 2,I am thinking of “stealing” 24V from the AMS plug to switch on my LED Riser. So wouldn’t need an external Power supply and the LEDs would be in sync with the Power switch of the printer…
Greetings kuhni

The most accurate way to measure power utilization is to measure current inline using a multimeter. Then using the equation Watts=Volts*Amps or in this case 24V=Watts/5A(usb).

The wattage I believe is labeled somewhere on the power supply but you may be forced to measure it yourself without the additional device and then measure it again after it is installed.

The safest thing to do is use a 24VDC to USB converter. Or if you are handy, buy a 24VDC buck converter and print your own case.

https://www.amazon.com/s?k=24vdc+to+usb+converter

https://a.co/d/dKck8Js

Here’s some plans on Printables using a DROK buck converter. They’ve already done the work for you. :blush:

https://www.printables.com/model/191311-drok-dc-dc-usb-buck-converter-case

Just keep in mind that USB 1.0 and 2.0 draw only 5Watts max power so that is 5Vdc at 1 AMP. Most LED’s draw far less than that. Also remember that power is pulled, not pushed, assuming you match voltages, the LEDs should be safe but that’s where the Buck converter does the heavy lifting so you don’t have to.

Now having said all that. Although what i suggested is well within my skill set to do, I tool the lazy way out and simply use a USB self powered hub and snaked the wire from the onboard USB port. It’s the safest - and easiest - way to wire. And did I mention they are so painfully cheap at under $5
https://a.co/d/i5KuaiD

I don’t need 5V. I will go for 24V. And I plan to use the bl Led Controller by Dutch Develop (The new BLLEDController Guide -)
The LEDs will draw at max brightness ~2A so ~50 Watts in total.
My question is:
Are 2 AMS (these are the ones I don’t use) drawing 50 Watts together? And do they only in peak or for a longer time? If both questions could be answered with yes, I can steal the 24v from the AMS plug. If no, I’ll have to use the external power supply…

Greetings kuhni

The idle consumption of an AMS ought to be very low and they should only consume when active (spooling filament). I suspect that only one AMS is active at a time, which would mean that in terms of load on the power supply it doesn’t matter much whether you have 1 AMS connected vs. 4. Given that your load is continuous, it seems to me that your overall calculation doesn’t work out.

Caution from Bambu Lab in here - with a couple of examples of how to do it.

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bambu data sheet says 3A@24V, thus 72W rated total power for AMS 6-pin port. Since up to 4 AMS can be daisy chained, I reckon there’s some headroom power you can use for LEDs. 2 Amps really sounds like on the high side, I have mine trimmed down to 0.7 Amps, running fine for many multi-hours prints so far…

Those ams are set up something like a canbus, stealing power will cause issues, if the ams will work at all.

Hi, can you explain why one can’t just use a 24v LED and connect directly without using a buck converter or anything else to step down the voltage? For example, if someone doesn’t have an AMS unit and wants to power LED chamber lights directly from the 4pin connector (by modding a cable) on the back of the printer. Also as far as I know the X1C doesn’t have any on board USB ports like the P1 series does.

Of course there will be disclaimers of these kinds of modifications but will this physically not work if the source is 24v and the LEDs are 24v?

I’m assuming that you are referring to LED strips not a discrete LED component which typically is using 3.3 or 5VDC discrete LEDs which are the most commonly found in industry and therefore the cheapest. A 24VDC strip already has the step down converter built-in and is commonly found in functional strip LEDs that one might find used in building architecture or inside custom limousines.

To answer your question. The choice is merely a design decision. If you have an LED strip that can accept 24VDC input power and the current draw doesn’t exceed the leg of the power that you are connecting, then this would possibly be a simpler wiring exorcise. But check the current draw since most of these I’ve looked at are usually higher current items because their intended use if for things like room lighting where many discrete LEDs are being powered.

The advantage to using a 24v to 5v buck converter is that 5VDC is the most common LED found in electronics simply because the USB 1.0 standard started out using 5VDC so the range of choices is greater.

In the end, it’s a tradeoff between simplicity of design, cost, and, quite frankly, in our world of makers, what one might have lying around in the shop.

This makes sense. And yes, I was thinking an LED strip.

Thanks and Merry Christmas!

Higher voltage LED strips typically have subgroups of elements in parallel. Using a step-down/buck regulator would be pretty unusual, but I guess anything’s possible.