I'm making this thread to gather all the power supply references from other threads into one, neat and tidy thread.
Power supplies:
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1.
12v car PC power supply:
www.powerstream.com/DC-PC-12V.htm
This gives you 12V, 5v, and 3v at high amperages, which will power sensors, servos, and lots of lights.
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2.
Standard PC Power Supply:
www.bestbuy.ca/en-CA/category/power-supplies/20380.aspx
Can be found everywhere! And if you want cheap, go to eWaste and pick out one for free-$20! Just get a high Wattage supply.
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3.
Courtesy @Steve_G from @fxrtst's Power supply thread:
"I had a bit of a search for you, and came up with the following fixed voltage supplies which was all from one website called TCR Electronics and are all under 100 bucks. Searching other sites pretty much came up with the same makes and models. The ones I've linked to are the best of the bunch that I think meet some of your requirements. I threw a couple of 20 amp supplies in as well in case anyone else is looking...
7.5v
40 amp
345 watts
215x115x50
$44.80 for 1 to 9 units (cheaper after that).
www.trcelectronics.com/View/Mean-Well/SE-350-7.5.shtml
7.5v
40 amp
300 watts
199x105x41
$76.50
www.trcelectronics.com/View/Mean-Well/HRP-300-7.5.shtml
7.5v
20 amp
150 watts
199x99x50
$43.90
www.trcelectronics.com/View/Mean-Well/SP-150-7.5.shtml
7.5v
20 amp
150 watts
199x99x30
$36.90
www.trcelectronics.com/View/Mean-Well/RSP-150-7.5.shtml
7.5v
32 amp
240 watts
190x93x50
$50.90
www.trcelectronics.com/View/Mean-Well/SP-240-7.5.shtml
And the smallest I found at a reasonable price, but at 20 amps...
7.5v
20 amp
150 watts
159x97x38
$47.70
www.trcelectronics.com/View/Mean-Well/HRP-150-7.5.shtml
Anything smaller in the way of form factor, and you're looking to pay out at three digit figures. The one other plus about this website is that they do bulk buy discounts too."
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4.
Courtesy @Steve_G from @Askwpccoach's "How Can I Provide Continuous Power To Jd From An Ac Outlet Or Battery That Will" Thread
"So a 7.4 volt, 20 amp power supply is what you will need to have JD working at his best along with a female mini deans socket. This switching power supply is a good example of what you would need, although if you look around, you can find cheaper power supplies. "
m.ebay.com/itm/TEKPOWER-USA-TP3020E-SWITCHING-DC-POWER-SUPPLY-VARIABLE-0-30-VOLTS-0-20-AMPS-/201413831219?nav=SEARCH
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5.
Courtesy @Mathprof from his "Usb or Ac-Dc Conversion as a Lipo battery replacement" Thread
"Ok, so a 20 amp supply is a good target. Just looking around a little, I found this:
P/N: RSP-150-7.5
7.5vdc Power Supply
Approx Power: 150 Watts
Max Current: 20 Amps
Enclosed 1U low profile 30mm, built-in active PFC function, built in constant current limiting, LED indicator for power on, adjustable output voltage, and universal AC input range: 85~264vac.
Dimensions: 199x99x30mm
More Info, Quotes, Purchase $36.90 ea."
www.trcelectronics.com/7.5-volt-power-supplies-chassis-1.shtml
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As for Tips, Give out your own! Post them below! More power supply references? Add them below following the numbering sequence.(Ended at 5)
Now you can reference one thread to give an answer instead of multiple ones with many posts to sort through.
Asked
— Edited
6.
Something that I think is relevant to EZ-B power is the following that was posted by Jeremie at EZ-Robot...
EZ-B v4 Data Sheet
So, if you're shopping for a switching power supply please do your homework. Find out what your max amp draw will from the motors you're using, what voltage (3.3v, 5v, 12, exc) and voltage type (AC or DC) they need and what voltage and type your plugging the PS into. This is the only way to choose the proper PS you need.
Finding one to buy after you know your numbers is another issue. I like to use Mean Well power supplies. Very well built and they offer a wide selection. Here is the master list of Mean Well AC-DC converters:
distributor.meanwellusa.com/webnet_usa/search/seriessearch.html
One more thing; @Steve mentions above and others have echoed that Lipo batteries are best for servos. I'm still not a believer in that theory. I don't have a single battery on my full size B9 Robot and have many High Power, regular and micro servos and a number of big DC motors. I have never had an issue with brownouts when any of them have started up or while they run. The trick is to get a PS and wiring that will handle the MAX power draw. Also as Steve mentioned correctly above, when supplying power to a big motor or servo that it's important to bypass the EZB and power the motor directly from the PS, Do not use the EZB as a power conduit.
Have Fun!
I just wanted to say, although LiPos are great for powering servos, I don't actually use them much now, and use NiMH packs as you can charge them while still operating a device (depending on amperage) which are great for low power "monitoring" modes such as security. As are bench supplies which I'm all for as well, as there are lots around that deliver good amperage for a great price. Great for static robots such as your B9 and for bench testing.
I haven't got around to it yet, but after helping Will out looking for a supply for his Alan head project that you may remember, I discovered very reasonabley priced mains power supplies delivering 20, 30, 40 amps and plan to get one myself for testing.
You also make very good valid points about switching supplies too. Very useful
Information to know.
Another thing I've learned about these power supplies is that as you choose units (within a curtain model number) with higher output voltages your available amps goes down. So you will have one unit that delivers 7.5 vdc and provides 40 amps and another that will deliver 12 vdc and only be able to supply 27 amps. You would have to go to a different model to get the higher amp capacity and it would probably be physically larger and more expensive. Like everything else in life.
Cheers!
Ron R
A 12v 20 amp supply would run an EZ-B no problem, but the EZ-Robot 7.4v servos connected to that 12v EZ-B wouldn't like it very much. You could power each servos through a drop down buck converter or linier regulator with an output voltage that matches the servos, but more importantly, the amp output would have to match too, to handle the servo inrush current and maximum holding torque. Supplying 20 amps to a servo is not a problem, as the servos will only take what current they need.
When using a step down converter or regulators, as well as output voltage, is the amp output too. You could be supplying 12 volts and 20 amp input supply through a 6 volt regulator for example, but if that regulator is rated for 3 amps output, that's all your servos will get... 3 amps which may not be enough for a servo. So you would need a buck converter or regulator that matches you voltage needs, but with a much higher current output.
In the first post in point 3, there are some links to some good 7.5v power supplies with high amp outputs.
One think to keep in mind, is when using a power supply, a linear power supply can stubble to supply their specified amperage which is a limitation to how these supplies are designed. Digital switching power supplies like the one I linked to below, and like the ones some computers use, are far better.
www.trcelectronics.com/View/Mean-Well/SE-200-7.5.shtml
Or for a high amp regulator..,
www.amazon.com/gp/product/B000MXAR12/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
As far as voltage; a computer power supplies will usually supply both 12 & 5 vdc and sometimes 3vdc. They are usually rated in Watts and you need to use Ohm's law to do the conversion to find out what they will be able to supply in amps. There is lots of info and youtube vids on the internet on how to both use Ohm's law and to use a computer PS as a power supply. Simply do a Google search on each subject and there will be a ton of links available to study and educate yourself. One thing to be aware of is how quickly a computer PS will be able to supply an inrush of a voltage demand. I've read that computer power supplies are slow to supply the demand of a DC or servo motor and you may have trouble with brownouts or even see the PS shutdown. I've not personally seen this issue but it's something to keep in mind when you're designing your power circuit.
Good luck and have fun!
Thanks to all for the info and feedback. I will dig deeper to meet my power needs.
Ron R
(But i think this {kudos to Cardboard Hacker and all those referenced} is a good place for the pictures and information i'm posting below as well as any feedback it may garner)
I attempted to follow the advice provided here (and in
"Amps, Volts, Power Converters and Power Supplies" https://www.ez-robot.com/Tutorials/UserTutorials/163/1 and other threads etc.)
I needed a power supply for a robot with 10 EZ-Robot servos, so i bought the Mean-Well RSP-150-7.5
7.5v
20 amp
150 watts
199x99x30
$36.90
www.trcelectronics.com/View/Mean-Well/RSP-150-7.5.shtml
I wired it as shown below:
For the AC power cord i snipped off the end of a computer power cord (Note: altho i read somewhere that the 'brown wire should be hot and the blue neutral, my multimeter said otherwise and i believed it).
I connected the barrel jack to the white and black via solid-core copper wire (taken from Romex 14/2 cable) as shown below:
(Note: i had a 12 gauge Romex wire but it was too big for the barrel jack)
And when plugged in, the barrel jack shows 7.4V as shown below:
The EZB is working, it connects to wifi and I'm able to move the servos and use them in scripts.
Still, I would like to get feedback from any veterans who have time to comment about this setup. I'm not a hardware guy, so i expect that there is room for improvement, ha.
Thanks -Richard 'twitch' R.
One thing I wanted to point out for you which is something I touched on in step 7
Multimeters in my tutorial you linked to,. You quoted...
Brown wires in AC are indeed Live or Hot and blue is Neutral (and if present, green/yellow is Earth). But here’s the thing. AC, by definition, is alternating current, so it is not polarised and current flows in both directions. Basically this means that you can actually swap the wires around and most of your AC devices would still work with no damage. This is why your meter said the opersite to what you read about wire colours. But with that said, not only is it good practice to use brown as Live and blue as Neutral, but there is a safety aspect too.
For an example, I’ll use a table lamp with an in-line switch. Some AC appliances, like lamps, have a switch on just one of the two wires, usually the Live wire. The outlet has a Live and a Neutral wire - the Neutral wire is connected to ground somewhere, either at the local sub-station or on the street outside your house. The Live wire is at 120V US or 240V UK, compared to Neutral.
In the lamp itself, the Live wire of the light bulb socket is at the bottom, and the Neutral lead is on the sides. Sticking your finger in a Live socket (not recommended) with the correct polarity it is much more difficult for someone to accidentally touch the Live wire or terminal.
So when using a correctly wired and polarised table lamp, switch and plug, there is a guarantee that the switch will disconnect the supply voltage on the Live side of the lamp. If the polarity is reversed, then the entire appliance is still live and energised even when it is off, and could be dangerous if you were changing the bulb and happened to touch the metal side of the bulb... as you will get seriously zapped.
DC (direct current) has to be connected the CORRECT way only.
So just for good practice, I’d suggest swapping your blue and brown wires to where they should be on your power supply (as long as the mains plug is wired correctly too).
Hope that helps.
However, my conclusion is still that the cable itself was mis-wired in terms of the blue and brown cable-color, and I had a bunch of measurement photos to show you in order to try to prove it, then I remembered, hey I still have the severed plug -- here it is:
Blue=LiveHot -- What do you think?
And Hi to Nomad 6R too -- this power supply does not have a switch (prolly you were thinking along these same lines as Steve G?).
Thanks for your feedback and any other comments are welcome!
Richard 'twitch' R.
here is a link for all kinds of switshes wires cables.these are up to 12 volt.
on/off swiths
Looks like this inline toggle switch supports 0-2A current
and i believe the servos will draw much more than that for short periods during inrush.
I have put a simple plug strip with on/off switch on the AC side for the power supply and that seems to be working so far.
best regards -Twitch
I tried the solution posted by Jeremie and DJ (in post #15 of https://www.ez-robot.com/Community/Forum/Thread?threadId=8686&page=2)
using two 1Farad 2.5V Aerogel caps in series and that seems to have solved the problem: i haven't seen a brown-out since. - Thanks for that thread and i hope others find this helpful. -Richard 'Twitch' R.
Here are some photos: