I would like to connect this thing to the usb slot on the backside and draw current from it. Does anybody know if if it’s possible? If so, how much current can the usbslot provide? I did see a similar topic @ Using usb drive connector to power led lights but there was no conclusion 
You’re referring to the filament dryer? Isn’t that about 50W? And likely 12V or 24V?
It is extremely unlikely the USB port would provide 50W even if you convert it to the right voltage.
I’ve tapped off of the 24V from the add on port to convert to 5V and 12V, but even then I’m not pulling 50W.
It’s unlikely the power supply in general has that much overhead without confirming with Snapmaker.
@Wombley sorry. I was reffering to the fan… 
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Ohhhhh! 
It’s probably safe to say it’s at least a 5V, 0.5-1A. Dunno for sure though.
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Thanks! That should be enough but I don’t wanna risk pulling more than the slot can provide. I Was hoping for exact information 
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Well, if it’s only a standard USB 2.0 port, and it may be, then it’s 0.5 A limit.
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It’s USB type B. I believe those are usually not meant for drawing current from but perhaps it can be done with this one…
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You’re probably already good to go. But. Another option is the Addon Port. It’s CANBUS with 24V output on the heavy pins.
The plug is a Snapmaker 2.0 DC power cable. Although the plug on the cable has a small key nub that makes a tight fit, unless it’s removed. Likely because it seems like if you cut it, the voltage polarity is backwards compared to the wire coloring.
But I used this to make a little power supply box with a fuse, 12V buck convertor for a PWM fan drive, and a 12V to 5V USB power board. To drive a Bento Box air filter fan and a Raspberry Pi 3B+ (Octoprint server).
IIRC, I have it fused to only draw up to about 24W conservatively and it’s been OK. Since I also don’t know its limit.
older usb types are 5v @ .5a which is only 2.5 watts
newer ones up this to .9 amps
a lot of these small fans are 5v and in the .2-.3 range for amps…you should be fine
go as low as you can for amps and stay under .5 amps. at .3 amps your supply won’t work as hard(heat) as .5 amps
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@Wombley That’s a nice little box! I want to make something similar, but with a wemos d1 mini + driver for a fan or 2…
@wilsonrobertt Thanks. Maybe i’m wrong but i was under the impression that output current from a usb port can only be assumed to be possible on the host side )usually USB type A or type C) acording to the spec you provided. This is a USB type-B socket, indicating that it’s on the slave/device side and therefore I risk damaging the device if I try to draw current from it?
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no worries. on my controller i have a usb-a slot that you would plug a flash drive into. its a 2.0 a350.
i will say that i don’t usually see a usb type b supply power. usually im plugging into it to send data or power to the device, such as a printer. in older times they were signature pads etc.
