24v Powersupply!

thezfunk · 03-14-2004, 05:32 AM

Ok guys for my project I need a 40x40 pelt. The highest wattage I can find is the 172 watt one on dangerden.com. If anyone has other options for me please let me know. BUT! That thing is rated like so:

Imax = 11.3 Amps

Vmax = 24.6 Volts

So...will 12 amps kill it? What are tolerances on these things. Can i run less volts and/or amps or more? The main question is were can I get an affordable 24v 12amp power supply for this. The best price I have found thus far is 181 bucks!

feathers · 03-14-2004, 05:41 AM

12 amps won't damage an 11.3 amp peltier.

You can run less volts and less amps = less cooling. You can run a little bit more amps than the rating if you're cooling the peltier sufficiently (ie. water). If you want a powerful peltier then you will have to use a 50mm unit. Why are you insisting on 40mm? If your waterblock/heatsink/coldplate won't accept a 50mm then change to one that can!

I can supply peltiers to 280 Watts or more but certainly not in 40mm!

thezfunk · 03-14-2004, 03:55 PM

It has to be 40x40 cuz thats the size that fits. I would have to do some MAJOR changes to get a 50x50 to work. I will do some brain-storming.

feathers · 03-14-2004, 03:58 PM

Is this for a waterblock or one of those mini-fridge things?

SexyMF · 03-15-2004, 12:31 PM

Do not exceed absolute electrical maximum ratings. They are really there for a reason. You will end up with an expensive small ceramic tile.

feathers · 03-15-2004, 12:40 PM

Yes.. Never go more than 20 amps above a peltier's maximum rating or more then 4000 volts on a 20 volt unit.

So why don't we apply this 'do not exceed' rule to overclock voltages and speeds?

Absolute ratings are indeed there for a reason but often you will find there is a little bit of tolerance beyond the rated limit.

And it do depend on the situation a component finds itself in..

Max ratings for voltage/current are quoted at a certain temp range.

If your component is operating at a much lower temp then you can usually buy yourself some extra capacity.

In essence: A peltier rated at 15.2 amps isn't likely to be adversely affected by an increase to 15.3 or 4 (or perhaps higher). Same applies to voltage. Especially if said peltier is watercooled.

Same applies to any electronic component. I've had a P4 2.4 core voltage raised to 1.9 volts. This is far in excess of it's rated voltage. I was able to do this because the CPU was being chilled close to zero celsius. I would not have pushed the voltage so far had I been cooling with heatsink/fan or just plain water.

arken420 · 03-29-2004, 01:04 PM

I was under the assumption that DC devices pulled amps, so your peltier will pull as much as it can given the voltage it is running. That 172W pelt is rated at 11.3A@24V, so you'll only get in trouble when you start powering it with more voltage, not more amperage. Anyways, what CPU are you cooling? AMD/Intel? They do make pelts with lower wattages that won't cool as well as a 172/226, but run on less AMPs, which will lower your PSU bill. 182 is a bit much for a PSU, especially since it's 24V, and therefore only good for running your Pelt.

If you have to have 40mm, then 131W is your best alternative, but I'm afraid that you'll be wanting something more. www.tetech.com is a good place to go and look for pelts. DangerDen actually gets theirs from there anyways. Oh, well, hope I haven't completely crapped your day.

thezfunk · 03-31-2004, 03:47 AM

I have a possible solution. I work in the surviellance industry and we use 24v 8amp power supply for cameras. Can anyone make an educated guess as to how much cooler I could get out of that thing with only 8 amps?

arken420 · 03-31-2004, 06:18 AM

Quote:

Originally Posted by thezfunk

I have a possible solution. I work in the surviellance industry and we use 24v 8amp power supply for cameras. Can anyone make an educated guess as to how much cooler I could get out of that thing with only 8 amps?

At 24V it'll try and pull 11.3 amps from your PS, so your PS will over-heat and maybe fail. The problem could be rectified with a lower voltage, thus a lower amount of amperage would be pulled. If you run it at 24V you really need all 11.3 amps. You could possibly run it at 15V-12V and it would pull significately less amps, ~6-8A. I haven't done any calcs on it, just guesstimating.

Butcher · 03-31-2004, 05:53 PM

You could use a 24V 200A supply if you could find one - the amount of current drawn depends on the voltage. Thus any power supply with at least 11.3A continuous output at 24V will do fine. More volts is not a good isdea though. Also note that peltiers are more efficient below their maximum voltage - as you approach and exceed maximum voltage you don't get much more cooling - the efficiency drops and the extra power is wasted (as heat off the hot side).

thezfunk · 04-06-2004, 12:32 PM

All great help...I managed to find a mean well at 24v 12amps for 98 bucks new which is awesome. I was looking for a 18v one but they make 15 or 24 not 18. Oh well I guess now that one is a semi reasonable price I can stick with the 24v plan...

03-14-2004, 05:32 AM	#1
thezfunk Cooling Neophyte Join Date: Mar 2004 Location: Wouldn't you like to know Posts: 33	24v Powersupply! Ok guys for my project I need a 40x40 pelt. The highest wattage I can find is the 172 watt one on dangerden.com. If anyone has other options for me please let me know. BUT! That thing is rated like so: Imax = 11.3 Amps Vmax = 24.6 Volts So...will 12 amps kill it? What are tolerances on these things. Can i run less volts and/or amps or more? The main question is were can I get an affordable 24v 12amp power supply for this. The best price I have found thus far is 181 bucks!

03-15-2004, 12:31 PM	#5
SexyMF Cooling Neophyte Join Date: Jul 2003 Location: NZ Posts: 26	Do not exceed absolute electrical maximum ratings. They are really there for a reason. You will end up with an expensive small ceramic tile. __________________ A7N8X Deluxe AMD 2600+ 512MB Corsair XMS DDR333

03-15-2004, 12:40 PM	#6
feathers Cooling Neophyte Join Date: Mar 2004 Location: UK Posts: 81	Yes.. Never go more than 20 amps above a peltier's maximum rating or more then 4000 volts on a 20 volt unit. So why don't we apply this 'do not exceed' rule to overclock voltages and speeds? Absolute ratings are indeed there for a reason but often you will find there is a little bit of tolerance beyond the rated limit. And it do depend on the situation a component finds itself in.. Max ratings for voltage/current are quoted at a certain temp range. If your component is operating at a much lower temp then you can usually buy yourself some extra capacity. In essence: A peltier rated at 15.2 amps isn't likely to be adversely affected by an increase to 15.3 or 4 (or perhaps higher). Same applies to voltage. Especially if said peltier is watercooled. Same applies to any electronic component. I've had a P4 2.4 core voltage raised to 1.9 volts. This is far in excess of it's rated voltage. I was able to do this because the CPU was being chilled close to zero celsius. I would not have pushed the voltage so far had I been cooling with heatsink/fan or just plain water. Last edited by feathers; 03-15-2004 at 01:54 PM.

03-31-2004, 05:53 PM	#10
Butcher Thermophile Join Date: May 2001 Location: UK Posts: 1,064	You could use a 24V 200A supply if you could find one - the amount of current drawn depends on the voltage. Thus any power supply with at least 11.3A continuous output at 24V will do fine. More volts is not a good isdea though. Also note that peltiers are more efficient below their maximum voltage - as you approach and exceed maximum voltage you don't get much more cooling - the efficiency drops and the extra power is wasted (as heat off the hot side). __________________ Once upon a time, in a land far far away...

03-14-2004, 05:41 AM	#2
feathers Cooling Neophyte Join Date: Mar 2004 Location: UK Posts: 81	12 amps won't damage an 11.3 amp peltier. You can run less volts and less amps = less cooling. You can run a little bit more amps than the rating if you're cooling the peltier sufficiently (ie. water). If you want a powerful peltier then you will have to use a 50mm unit. Why are you insisting on 40mm? If your waterblock/heatsink/coldplate won't accept a 50mm then change to one that can! I can supply peltiers to 280 Watts or more but certainly not in 40mm!

03-14-2004, 03:55 PM	#3
thezfunk Cooling Neophyte Join Date: Mar 2004 Location: Wouldn't you like to know Posts: 33	It has to be 40x40 cuz thats the size that fits. I would have to do some MAJOR changes to get a 50x50 to work. I will do some brain-storming.

03-14-2004, 03:58 PM	#4
feathers Cooling Neophyte Join Date: Mar 2004 Location: UK Posts: 81	Is this for a waterblock or one of those mini-fridge things?

03-29-2004, 01:04 PM	#7
arken420 Cooling Neophyte Join Date: Oct 2003 Location: Kailua, HI Posts: 31	I was under the assumption that DC devices pulled amps, so your peltier will pull as much as it can given the voltage it is running. That 172W pelt is rated at 11.3A@24V, so you'll only get in trouble when you start powering it with more voltage, not more amperage. Anyways, what CPU are you cooling? AMD/Intel? They do make pelts with lower wattages that won't cool as well as a 172/226, but run on less AMPs, which will lower your PSU bill. 182 is a bit much for a PSU, especially since it's 24V, and therefore only good for running your Pelt. If you have to have 40mm, then 131W is your best alternative, but I'm afraid that you'll be wanting something more. www.tetech.com is a good place to go and look for pelts. DangerDen actually gets theirs from there anyways. Oh, well, hope I haven't completely crapped your day.

03-31-2004, 03:47 AM	#8
thezfunk Cooling Neophyte Join Date: Mar 2004 Location: Wouldn't you like to know Posts: 33	I have a possible solution. I work in the surviellance industry and we use 24v 8amp power supply for cameras. Can anyone make an educated guess as to how much cooler I could get out of that thing with only 8 amps?

04-06-2004, 12:32 PM	#11
thezfunk Cooling Neophyte Join Date: Mar 2004 Location: Wouldn't you like to know Posts: 33	All great help...I managed to find a mean well at 24v 12amps for 98 bucks new which is awesome. I was looking for a 18v one but they make 15 or 24 not 18. Oh well I guess now that one is a semi reasonable price I can stick with the 24v plan...

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