12" i3v Current Requirement

[ex-egll]

Hi, just trying to work out what power supply to use for the 12" i3v. Has anybody taken current readings from their setup?

In particular, I would be interested in the current draw of the bed vs the total draw. I get a feeling that a 30A supply would be nearing its limit, and I may be better off either with a 40A supply, or a 30A supply dedicated to the bed and a ??A supply for the rest of the printer.

[N5QM]

The references I have seen say that the 12" printer will use nearly all of the capacity of a 30A power supply.

I would probably choose to use something with more than 30A of capacity.

Please take into consideration that I am a n00b, so I'm not sure my opinion is even worth 0.02.

Robert

[printbus]

At the currents required for the heat bed on the 12-inch printer, wire resistance can be significant and affect the heater current draw substantially. To minimize power losses in the cabling and reduce bed heat-up time, it is usually a good idea to go with some beefy wire from the power supply to the heat bed relay and possibly even replace the lighter gauge wire that comes preinstalled on the heat bed.

I only have an 8-inch printer, but from what I've read others doing, N5QM is probably correct. Those that have really optimized their wiring to minimize cable losses have been pushing the limit on their power supplies.

[sniffle]

I can honestly tell you that a 12V 30A power supply handles the current requirements of the 12" just fine and heats up without issue. I hit 120 degrees on the bed and 250 on the hot end in around 5-6 min.

It may push it near it's limit but it handles it just fine :-)

and to add to what printbus said, The 12" printbed comes stock 12 12AWG wire, and i used 12AWG from the power supply to the relay

[printbus]

Sniffle, just to be clear - you only have the one power supply on your printer? It's good to know the heat bed is prewired with 12 gauge. I didn't know that.

TechMasterJoe had measured 29.7 amps on his, including I believe the cartridge heater and the motors being driven.

[ex-egll]

Thanks for the input. Also interested to learn that the 12" has 12 gauge prewired. I was planning on using 10 or 12 gauge for the high current paths anyway. 29.7A is pretty close to the limit, I am not sure how much one of the 30A LED power supplies is really capable of. I think I will go with a 40A p/s, that way I'll have a little to spare if more additions appear later on.

[pichuete]

i had the same question when i build my i3v 12" . i bought one of those cheap LED 12v 30A PS and Failed after a day of use . i guess the amperage draw is almost 30A so if you have a bad quality PS probably will fail . Im currently using a 900W 75A Server Power Supply . its a little overkill for the demand but my printer is running pretty good now . Actually the bed Reaches 95C faster than my Extruder (2min) . Also is smaller and same price as a 30A PS .

http://www.ebay.com/itm/221583582668

[sniffle]

yes printbus i only have one power supply that runs the entire printer, I may have gotten lucky with my power supply though and i realize that fact.

[usarmyaircav]

pichuete, that PS looks nice! I will keep that in mind if my LED ps give up.

[ex-egll]

pichuete, thanks for the pointer. Ordered one of the 47A ones.