12V vs 24V

I plan to build a GUS with RAMPS, no heated bed and a geared extruder. What are the advantages and disadvantages of 12V and 24V?

24 volt is better if you have a higher wattage large build space machine as the current drawn is half for the same wattage and you can use lighter wires. If you have no heatbed then 12v is fine.

Does that mean that the only benefit of 24v is the lighter wiring?

If you are building a Delta and the stepper RPM's matter, (a lot depends on the design and what you plan to do) and you buy the right motors, 24V may get you to twice the RPM's that 12V will.

With 24V, you will need to also have a 12V supply to run the fans and to supply the Mega board's regulator. Depending on what your hot end is set up for, you may need to run it on 12V.

RPMs do matter, though GUS seems quite quick either way. I have several wall warts sitting around that I use with my Arduino Uno, and I could presumably use a USB phone charger.
Is 24V worth it given that I'll have to much about with caps on the RAMPS? Or should I just switch to an Azteeg X3?

Quote
epicepee
RPMs do matter, though GUS seems quite quick either way. I have several wall warts sitting around that I use with my Arduino Uno, and I could presumably use a USB phone charger.
Is 24V worth it given that I'll have to much about with caps on the RAMPS? Or should I just switch to an Azteeg X3?

"to much about with caps" = ?

You will need +12 for fans. You may need it for other things. If you go with a 24V system, just get a $10 12V industrial supply to do the 12V stuff.

12 or 24 volts, none is really better... its what ever your system uses...
I tend to always go with higher voltage, especially with my electric vehicles, but with these printers they don't use much power anyway, so 12 or 24.. does not matter..
I think 12 volt setup would be easier as most people run this voltage and id suspect there is more support for 12 volt repraps... who knows what issues you will come into with higher voltage...

and for wiring... I would not bother going to 24 volts to get smaller wiring in, its already small enough for the amount of current, like my printer sucks at most 100 watts with out heated bed.. my heated bed is a separate circuit all together.


When it comes to my electric bikes, I use heaps of voltage like over 100volts, it really matters in this case.

24v is better for running your steppers on, and you can set the max pwm value to 63 to use it on the hot end and heated bed, you would need to supply power to the arduino using a small 12v supply which could also power your fans.

Running a 12V heated bed or extruder off of 24V by changing the PWM value is not a real good idea. The heated bed that pulls 10-15A (120 to 180W) will be trying to pull 20 to 30A off of the 24V supply while the PWM is on. The power dissipation in the FETs goes up as the square of current. The same is true of heat in the terminal blocks. Neither one will be very happy with what's going on.

There are a number of other possible voltages you could do. A 15V industrial supply lets you get to 13 to 17V by adjusting the pot. Fans probably are happy at 15V. With a fan on it, the Mega regulator probably is happy at 15. There still would be the issue of heated bed current.

There is an arduino that can take 24 volt called the Taurino Power. [reprap.org]

It's a lot cheaper to drop a 50 cent chip on a normal Mega that it is to buy a Taurino. Either way you still need to power your fans. You will spend far more on a couple of 24V fans than the $10 cost of a very good 12V supply.

[www.hobbyking.com]

place to buy power supplys, I run my printer on a 350 watt hk branded one


I would personally prefer to use as much fanless stuff as I could...

Edited 2 time(s). Last edit at 12/23/2013 09:20PM by nechaus.

[www.trcelectronics.com]

Much better place to get power supplies.

1) They are a name brand and there is a real warranty on them
2) TRC is a big distributor, you won't get fakes
3) Shipping is *much* faster and cheaper
4) They run off of 110V and / or 220V
5) They are the same price / cheaper / within 10% depending on which one you look at.
6) On a 350W supply a fan is a *very* good idea as long as it only comes on when it's needed.


Yes if you are outside the US, shipping may not be faster. MeanWell has distributors all over the world. Pick one near you.

I've had several of the Chinese "clone" power supplies do odd things. Mostly they blow smoke and die. I have not had one trash anything when they died (yet). I stopped buying them a while back.

meanwell ones are very good, nice body, i have a couple laying around here but they are more expensive..

honestly hobbyking is not that bad, iv had some dodgy products in the past like portable usb chargers that never actually worked and the warranty process is more annoying so i just took it as a small loss..
I use the 1200 watt power supplies daily but for only a couple of hours at a time, never had a problem..

my 350watt hk one has been left on for weeks, The fan is always on.. i had two of these, i dropped one and the housing busted apart, crack the plastic case, but it still works..
they are not as efficient as what i would like but meh, its cheap yet still reliable


most products from hobbyking are good, they are my number 1 source for lithium batteries, lately i have had some with higher internal resistance, for spending thousands on batteries, iv had a really good run with that company...

blown plenty of rc controllers tho, they are mostly junk, had the fatboy 300, that was the only esc that i really liked... but i use sevcon or kelly controllers for my ev stuff.


for $29 this is a decent deal, lets you see the current draw as well which could be handy for some basic diagnostics
[www.hobbyking.com]

Edited 1 time(s). Last edit at 12/24/2013 07:30PM by nechaus.

Do what you will. I don't like fires very much. I know for *sure* that Hobby King does not make power supplies. I strongly suspect they are not as careful about the sourcing of the electrolytic capacitors as they might be. At least when I looked, the 350W 12V supply was $3 cheaper from them than from the MeanWell guys. That's before shipping.

The lower power supply really isn't enough for most of these printers....

I wouldn't need much power, actually
No heatbed, say 1.5A per stepper and 3A for the hotend, that's only 9A total, so a 14A, 15V power supply would easily be enough. Am I missing something?

Also, are 16V power supplies common, or could I get a 15V PSU to put out 16V? That's the rating on the RAMPS's caps, and I have. 12V wall wart for the Mega.

Edited 1 time(s). Last edit at 12/25/2013 02:30AM by epicepee.

My printer only uses 6 or 7 amps 3dsm advise 5 amp psu.
Heated bed uses way more
A 12 volt car charger will be like 15 or 16 volt

Edited 1 time(s). Last edit at 12/25/2013 03:40AM by nechaus.

I use Toshiba laptop 15v 6A power supplies on all my printers and most Tantillus users do too. It helps with shorter step pulses and faster heat up of the hotend while still being within the capabilities of the regular Arduino power regulator.

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If you ever do decide to go with a heated bed, you may need another 15A ....

I wonder what the most efficient setup for a heating bed is?

im thinking it would be like some kind of bed that takes a long time to heat up and retain the heat?
I almost was going to take my printer outside the other day and let it sit in the sun to see how it would go with printing..

I wonder if a heatlamp would work. Or a 110v heatbed.

Since you want to change temperatures while you are printing, a slow heated bed is not a good thing. Ideally you want to go from 100C to 110 or 90 in under a minute.

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110V is not a good idea running around a machine that's built like one of these printers. It's likely to kill you. It's also not as easy to control as low voltage DC.

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A heat lamp would either:

1) Need to be below the bed and track it as it moves (difficult to set up)
2) Be above the bed, still tracking, (also difficult to set up). It would heat the print more than the bed. That's not ideal.

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A "fast" bed is more efficient in terms of power use. You don't put as much energy into it getting it hot. A bed that heats on full power for 5 minutes, uses less energy than one that heats on full power for an hour before you can use it. The long cool down on the second bed has no real value. You keep heating it until the print is done (to keep it accurately at temperature) and then shut it off. Waiting an hour for it to cool down does not improve the print in any way. It's also a pain to wait for ....

How much of an improvement would 15v or 16v be over 12v, stepper-wise?

With normal steppers doing normal printer sorts of things, 12V works fine. There is no real benefit to the higher voltage. That said, your max RPM goes up in direct proportion to the supply. If you bump the supply 10% your max RPM's go up by 10%. If you need lots of RPM's on your printer, you want to go to 24 or 36 or 48V.

Edited 1 time(s). Last edit at 12/26/2013 05:36PM by uncle_bob.