16v step up transformer

[Hackentosher]

So i have a stupid idea for a ridiculous 120mm fan that will need 16-17 volts at 30 amps. Does anyone have any ideas of how I would go about making the step up converter, or where I could find one that can pull that kind of current? 

[W-L]

7 minutes ago, Hackentosher said:

So i have a stupid idea for a ridiculous 120mm fan that will need 16-17 volts at 30 amps. Does anyone have any ideas of how I would go about making the step up converter, or where I could find one that can pull that kind of current? 

Is that DC voltage or AC, and what are you trying to do exactly since 30 amps is a huge current draw if that's operational current. 

[Pesukarhu]

If you don't care about efficiency, use a BIG resistor with two car batteries in series. It will be inefficient as hell but it should work. I have yet to come across a regulator that could handle 30 amps at 16 volts. Also, why 16 volts?

[Hackentosher]

37 minutes ago, W-L said:

Is that DC voltage or AC, and what are you trying to do exactly since 30 amps is a huge current draw if that's operational current. 

It is DC, and mini quad motors can pull a lot of current, upwards of 25 amps. 

 

31 minutes ago, Pesukarhu said:

If you don't care about efficiency, use a BIG resistor with two car batteries in series. It will be inefficient as hell but it should work. I have yet to come across a regulator that could handle 30 amps at 16 volts. Also, why 16 volts?

I need it to run from within my comluter, so I'll have to wire some molex connectors together. As for why 16 volts, well a 4s battery when fully charged is in the 16v range. Essentially I want to build a fan that moves far too much air. 

[W-L]

3 minutes ago, Hackentosher said:

It is DC, and mini quad motors can pull a lot of current, upwards of 25 amps. 

I need it to run from within my comluter, so I'll have to wire some molex connectors together. As for why 16 volts, well a 4s battery when fully charged is in the 16v range. Essentially I want to build a fan that moves far too much air. 

If your wanting to use this in a PC why not go the easier route and get some Delta fans they pull crazy amounts of air. As for quad motors that max current would be under load or having to lift off so if it was just moving air it would be at a much lower current. 

[Hackentosher]

2 minutes ago, W-L said:

If your wanting to use this in a PC why not go the easier route and get some Delta fans they pull crazy amounts of air. As for quad motors that max current would be under load or having to lift off so if it was just moving air it would be at a much lower current. 

Eh, because I have a couple arduinos and Cobra 2204 2300kv motors. I'd just need an esc and the parts for the transformer. 

 

Anyway, I know that with a 5" triblade prop, that motor can easily pull upwards of 25 amps at full throttle and nearly a kg of thrust (mounting will be interesting). I believe in the end it will be more air than a delta. 

[W-L]

3 minutes ago, Hackentosher said:

Eh, because I have a couple arduinos and Cobra 2204 2300kv motors. I'd just need an esc and the parts for the transformer. 

 

Anyway, I know that with a 5" triblade prop, that motor can easily pull upwards of 25 amps at full throttle and nearly a kg of thrust (mounting will be interesting). I believe in the end it will be more air than a delta. 

Better bolt down that PC or lift off! 

 

Yes it would be definitely more airlfow than a delta for sure as most of those can easily hit 15K RPM, but if you really want to give this a try I would for sure run it off of a separate PSU, the motors should run at 12V but may not at full speed, only thing I can think of capable of taking such high amperage would be an oversized buck boost converter. 

[Hackentosher]

3 minutes ago, W-L said:

Better bolt down that PC or lift off! 

 

Yes it would be definitely more airlfow than a delta for sure as most of those can easily hit 15K RPM, but if you really want to give this a try I would for sure run it off of a separate PSU, the motors should run at 12V but may not at full speed, only thing I can think of capable of taking such high amperage would be an oversized buck boost converter. 

Hmm okay, I have a cx 430 that I modded to have two 12v lines over the stiffest 12 awg you've ever seen, but that's the supply I'm using to power my charger. I have another 300w atx supply, but it's super sketch. I pulled it out of a 2008 gateway pre-built, but I think I can mod it to get the job done. 

[W-L]

2 minutes ago, Hackentosher said:

Hmm okay, I have a cx 430 that I modded to have two 12v lines over the stiffest 12 awg you've ever seen, but that's the supply I'm using to power my charger. I have another 300w atx supply, but it's super sketch. I pulled it out of a 2008 gateway pre-built, but I think I can mod it to get the job done. 

As long as your not putting it to the max of 30amps the 430W alone should work. This would be interesting to see how things turn out  

[Hackentosher]

18 minutes ago, W-L said:

As long as your not putting it to the max of 30amps the 430W alone should work. This would be interesting to see how things turn out  

Oh shit, I just realized how many watts this thing will pull 0.0... I guess I'll have to dedicate my sketchy supply to charging

 

 

[mariushm]

Regular transformers convert one AC voltage to another AC voltage. So, they won't really be of much use if you plan to use the 12v DC output of a power supply.

 

What you need is a DC-DC converter, to step-up (boost) the 12v to 16v. Alternatively, you'd buy a 18-19v laptop adapter or a 24v power supply and create a step-down (buck) regulator to take this voltage down to 16v. If you do step-down, you could in theory also use cheaper designs, for example linear regulators to take the voltage down to 16v at somewhat lower efficiency.

In either case, 30 A of current is a huge amount for a single DC-DC converter, it would be much easier to have 2 or 3 regulators each capable of 10-15A max.

 

Ti.com has a cool tool called Webench which allows you to make a dc converter quickly using their components, and they also give you example circuit and suggested components for mosfets, diodes, resistors and capacitors.

But, since you don't even know about transformers and how they work it probably makes no sense to suggest circuits because you wouldn't be capable to build up the circuits yourself.

It would be easier to just search eBay to find ready made step-down regulators capable of 30A or more and pair that with a 24v power supply capable of at least 16v x 30A = 480w (I wouldn't trust an eBay bought product to boost 12v from a power supply at currents like 30A).

 

Note that boost DC-DC converters will typically have an efficiency of about 90% or less, so if you want to boost 12v and create 16v at 30A (480w) you'd need a power supply capable of providing at least about 550w on 12v, a figure which is usually found in 750w or higher rated computer power supplies.

[Hackentosher]

3 minutes ago, mariushm said:

Snip

Well 30 amps is a little exaggerated. The cobra 2204 2300 isnt the most inefficient thing ever, but I still expect it to pull about 25 amps at full throttle (granted that's at the 16.8v of a full 4s lipo, but I think that 16 would be fine. 

 

If you read the rest of this thread, you'd know that this needs to sit inside my computer and thus must be compact. I can throw an arduino just about anywhere and the same for the ESC, but id like to have as few components as possible for the power delivery system. I've realized that a couple molex connectors off my 600w supply on top of the load from my system itself will not cut it, so I'm hoping to use what I have and spend as little as possible.  

[Huntsman]

Try... rewinding a microwave oven transformer then some beefy rectifier diodes to get the DC? Probably need to parallel a few diodes but it is do-able.

[Hackentosher]

42 minutes ago, Huntsman said:

Try... rewinding a microwave oven transformer then some beefy rectifier diodes to get the DC? Probably need to parallel a few diodes but it is do-able.

I might end up just going with 12v. Mini quad motors are still really powerful, even at 3s voltages. 

[mariushm]

Most ATX power supplies will allow you to adjust the output voltage by some degree with minimal hacks. Just by changing a resistor or something like that, it should be possible to raise the output voltage to about 12.6-13v - 12.5-12.8v is still within acceptable 12v output so computer hardware should work (some hard drives may hate seeing more than 12.5v though)

 

By disabling the over voltage protections (desoldering/changing a resistor or a few parts around the protection chip) some power supplies will work easily up to 13.5-15v.

 

Some will work even higher than this, but you'd have to change more parts  (like changing output capacitors rated for 16v max to 25v rated capacitors) and the transformer and rectifying components aren't really rated for such high voltages, the transformer may overheat and the efficiency of the power supply may drop.

 

[Hackentosher]

2 minutes ago, mariushm said:

Snip

 

Um no. My cx600m already sounds like it's about to explode, I don't want to provoke it. If I stuck to 12v, I wouldn't pull anywhere near 30 amps, 20 at the very maximum. I could use my spare 300w sketch supply sitting my closet.