Power supply for Quadcopter - Page 1
Forum section: electronics / general

author: joegtp
author_rank: Contributor
timestamp: July 29, 2010, 02:00:45 pm
content: I'm building a Quadcopter similar to thishttp://aeroquad.info/bin/view. While I'm tweeking the settings I would like to run the electronics and motors off the mains. I have a bench adjustable power supply (Mastech HY3003D) but it is only rated for up to 3A. Based on the specs of the motors (http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=5690), which I'm still waiting for, each motor can draw up to 18Amps at 11V. When I get them, I'm going to run them off the battery and hook them up to my multimeter to see the actual draw. But if the specs are right, and we multiply it out...4 (motors) * 18A = 72A72A * 11V = 792WAccording to the web site I'm basing my designs off of the battery (http://www.hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=7634) I ordered should be enough.I can't really justify spending $$$ on a bench power supply that goes that high. I've build power supplies in the past that go up to 2-3Amps but this is way out of my league. Does anyone have any thoughts on where I can get a high amp power supply that outputs 11V for cheap? I've looked into ATX computer power supplies 12V output but the motors specifically say 11V max.

author: NiHaoMike
author_rank: Super Contributor
timestamp: July 29, 2010, 02:05:05 pm
content: Connect a diode or two in series with the ATX power supply.

author: TopherTheME
author_rank: Regular Contributor
timestamp: July 29, 2010, 05:19:36 pm
content: Quote from: NiHaoMike on July 29, 2010, 02:05:05 pmThats going to be one hell of a diode to handle 72 amps.I think your best off just testing things from the batteries and nixing the power supplies. Most power supplies (even those expensive ones) are usually designed for steady state power output and don't like heavy transient operation that your quadcopter is going to produce.EDIT: The motor you linked to is rated up to a 3S1P lipo pack. Thats 22.2 volts, not 11. Do your self a favor and design your quadcopter based on a 22.2v battery supply and not 11v. It will make your copter lighter and more efficient.Ignore this. Although, using a 22.2v system would still be better.

author: DavidDLC
author_rank: Frequent Contributor
timestamp: July 29, 2010, 06:47:51 pm
content: Use individual diodes, one per motor.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 29, 2010, 07:11:10 pm
content: Quote from: TopherTheME on July 29, 2010, 05:19:36 pmput 72 nos of 1A rated diode in parallelit happened i was about to reply just after nihaomike's post, but i have no strong reason for it... now, it was just a question of why do you want the mains power supply? why dont a battery? whatever... lipo? LAcid? mains psu is less portableand you are going to need larger than normal ATX PSU (more expensive), at least 750W, i think it should be 1000W to take into account the loss factor, and if its 12V you are using. 22V? @ 72A? thats 1.5K++ watt! cray zee!i think that one quadcopter can lift a man

author: sigxcpu
author_rank: Regular Contributor
timestamp: July 29, 2010, 08:45:22 pm
content: 3s is 11v, not 22.

author: cybergibbons
author_rank: Frequent Contributor
timestamp: July 29, 2010, 08:59:40 pm
content: Quote from: TopherTheME on July 29, 2010, 05:19:36 pm3S1P - 3 cells in series, giving approx 3 x 4.2V, then with drop across an ESC, you are down at the 11V. 22V will fry it.

author: TopherTheME
author_rank: Regular Contributor
timestamp: July 29, 2010, 09:20:56 pm
content: Quote from: sigxcpu on July 29, 2010, 08:45:22 pmwoops, my mistake. I'm to used to using 7.4 packs.

author: joegtp
author_rank: Contributor
timestamp: July 30, 2010, 06:04:50 pm
content: Quote from: shafri on July 29, 2010, 07:11:10 pmI would like to run off mains so that I can spend as long as I want tweaking the setup. I've read that quads will go through batteries in 15minutes which will be quite frustrating since the PID and code tweaking will easily take longer than that.I may need to just buy a couple more batteries and cycle through them. I'm still going to need to track down a power supply for the ~80W battery charger I bought, for that I'm definitely looking at ATX power supplies.

author: Simon
author_rank: Unknown
timestamp: July 30, 2010, 06:17:26 pm
content: why not use a car battery ? keep it on charge so that it will you the peak currents you want and will keep charging when your not using it, you can get some hefty diodes these days for not a lot, I got 120A diodes off farnell for £1.8ish, they have a 0.5V drop