HIC i3 - Power Supply Upgrade

[Chip Luck]

I noticed when pre-heating the hot-end and in particular the bed, the x-axis motor fan would slow down. After probing the 12V power supply input to the RAMPS control board the following was observed, a very badly regulated and very underrated Power Supply (PSU). Also the 16AWG wires feeding the RAMPS board from the PSU was only 16AWG and I changed it out to 12AWG feed wiring. Original PSU rated 12V@20 amp, new PSU rated 12V@30 amp.

Here is very telling terse voltage table according to load, ORIGINAL=stock PSU and wiring, NEW=new 12V@30 amp PSU, NEW/12AWG = new 12V@30 amp PSU and changed wiring to 12AWG:

ORIGINAL NEW NEW/12AWG
12.16......12.16....12.16 = No-load voltage at boot
9.85.......11.72....11.94 = Bed only pre-heating
11.13......11.92.....12.1 = Nozzle only pre-heating
9.65.......11.64....11.91 = Hot-end AND Bed pre-heating

Big improvement! The Bed and Hot-end even heat faster, prints have appeared to have been more consistent (I never checked actual voltage at the Bed nor Hot-end during pre-heat). I strongly suggest if you have the stock HICTOP PSU that you upgrade it. Be prepared to tweak you printer calibration after the upgrade. Yes, it does fit the stock HIC i3 power supply mounting plate using the 4 inner screw locations. You will need 4 each 4x5mm screws for mounting, I found some spares in my original HICTOP supplied hardware kit.

Power Supply (PSU), 12 volt 30 amp was purchased here for $23.97 with Amazon prime free shipping, it arrived in 2 days:

Here is the new compared to the original (new is obviously larger):

Here is a bottom view showing 12AWG wire between PSU and the RAMPS control board. I used stick on wire management attached to the rear aluminum rail to hold the cabling.

[chenry76]

Do you have a link to the power supply?

[Chip Luck]

Do you have a link to the power supply?

Got it here though Amazon:

And make sure you upgrade the wiring between the PSU and the control board to minimum 12AWG.

Chip
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[chenry76]

Not sure if its just me but there isn't a link. Here is what I found on Amazon: Here

[LePaul]

I didn't see a link either

Also noticed large gap from your post (seems big for a small post)

[Chip Luck]

Not sure if its just me but there isn't a link. Here is what I found on Amazon: Here

That is the one I used.

[chenry76]

Thank you Chip Luck. I'm sure when I get brave enough to start messing with the firmware I'll have more questions. But for right now I'm getting good results. The only thing I don't like is not being able to save the printer setting via the LCD.

[Chip Luck]

Thank you Chip Luck. I'm sure when I get brave enough to start messing with the firmware I'll have more questions. But for right now I'm getting good results. The only thing I don't like is not being able to save the printer setting via the LCD.

Try running the Repetier Host program hooked up via USB cable to your printer. It will give full manual control and print job preview and run time status and control over your printer. Good luck!

Chip
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[blc]

Here is very telling terse voltage table according to load, ORIGINAL=stock PSU and wiring, NEW=new 12V@30 amp PSU, NEW/12AWG = new 12V@30 amp PSU and changed wiring to 12AWG:

ORIGINAL NEW NEW/12AWG
12.16......12.16....12.16 = No-load voltage at boot
9.85.......11.72....11.94 = Bed only pre-heating
11.13......11.92.....12.1 = Nozzle only pre-heating
9.65.......11.64....11.91 = Hot-end AND Bed pre-heating

Holy crap, you're getting some nasty voltage dips there... I'm still on the stock PSU and power cable, but mid-way during a print - with bed, nozzle, and motors all running - I'm getting 11.6V at the board. Maybe I got a better PSU...? Not sure if the fact that I'm on 240V mains here might make a difference either...

[Chip Luck]

Interesting, maybe you got some upgraded wire also?

Seems impossible to get 11.6V at full load with 16AWG wire. Your PSU might be good, but when I was using the OEM 16AWG wire and the NEW PSU I got a .6 volt drop. Upgraded the to 12AWG and negligent voltage drop. Do the math, do you want 30 amps running through 16AWG wire? I assume you have a HIC i3 also?

Chip
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[Chip_M]

I too noticed that the fan speed dropped whenever the bed heating clicked in on our HIC i3 (acrylic frame model) with the stock power supply and wiring. I also noticed that the wiring from the power supply to the RAMPS board was getting HOT, so it was clear that the wire from the power supply to the RAMPS board was undersized. I swapped out the OEM wiring with some 12 gauge cable, and the overheated on that wire was gone...but another problem developed: the wiring from the RAMPS board to the heated bed was overheating even worse than before, and it actually melted the connectors on the RAMPS board itself!

Looking at the current draw specs for the heated bed, I decided that I wasn't comfortable drawing that much current through the FETs on the RAMPS board or through those wimpy connectors. I purchased a generic automotive control relay rated at 40 amps and drove the control coil of the relay from the RAMPS board heated bed connection; you need to include a reversed diode across the control coil to snubber the voltage spike you get when you switch the coil on and off, there are details on the .net. I then wired the heated bed through the relay contacts directly to the power supply using some more of the 12 gauge cable, and I included an in-line fuse (automotive blade fuse) just for some extra protection.

The result is no more cable overheating, faster hot end warmup, faster heated bed warmup, stable hot end and bed temperatures. One consequence of using the relay is that you can't used PID control of the bed heating, but I don't find that to be necessary. I wouldn't use a relay for the extruder hot end, since it's current draw is pretty small compared to the heated bed. I haven't checked the voltage levels at the board as the heated bed cuts in and out, but I think they are pretty stable. No detectable change in fan speed.

Here's the fried control board:

The board connections were so munged up that I just added some pigtail leads and bullet connectors to that I could attach to the control relay. Still using the original power supply; it seems to handle the load just fine.

[Chip_M]

Just an update... I did some voltage measurements at the RAMPS board to see what effect the relay modification and upgraded wiring had.

Idle (no heating): 12.41 V at input to board

PLA Preheat (bed and hot end): 12.39 V at input to board.

Essentially no voltage drop at input to board. Works for me!

[Chip Luck]

Just an update... I did some voltage measurements at the RAMPS board to see what effect the relay modification and upgraded wiring had.

Idle (no heating): 12.41 V at input to board

PLA Preheat (bed and hot end): 12.39 V at input to board.

Essentially no voltage drop at input to board. Works for me!

Glad to see it's working for you. I also am going to add a relay as you did, just have never had a chance yet.

[KevinA]

I got mine from seller philipsxenon on Ebay out of Nevada for $15.95 free shipping. I have some 001 welding cable in the shed, wonder how that will work.

[mr_nobody]

Guys, to help prevent melted connectors like this be sure to tin the wire ends with good quality solder before you put them in the connectors and tighten them down. This type of failure is caused by resistance between the connector and wire which generates more heat as current rises. When the copper is exposed it will oxidize and generate resistance between the individual strands of copper. Those connectors are cheap and underrated for the amount of current being drawn so this will give the connection the best chance to survive. Also note that the cheaper copper wire tends to oxidize much faster than quality brands/grades. I even saw a guy's video on YouTube that bought another i3 kit brand and noticed that the connections on the heat bed were not soldered well. He went to re-solder the connections and found that the copper wire was oxidized all the way through as he kept stripping more insulation back and could not be tinned. He said they must have kept the spools in a bucket of water or something. He threw it away and used new wire. When I build my 3DP18 kit tomorrow I plan to do this and also use some DeOxit on the connectors. I dunno if the DeOxit will help in this case but I got a bunch of it and I tend to put it on everything. Hope this helps.