I tested a lot of Castle products over the years. Their BECs are actually among the best you can get. A BEC like this is meant for high powered airplanes or helicopters which would have ridiculously high airflow and it's generally assumed that you will mount it as such. It's also worth mentioning that the dominant load on these BECs is servos so it's virtually guaranteed that peak loading will never happen for more than a few seconds at a time. Check out their ripple and transient stability if it's anything like their entry level BEC it should be good.

25:25 - It likely failed at the 15A output because Dave's supply was only outputting 15.2V AT THE POWER SUPPLY. While relatively small there will be a voltage drop over those leads at the required current (7A+). Plus the manufacture listed 16V not 15V as the required input voltage. If it only needed 15.2V they would have marked it 15V and not 16V.

The reason it goes down to those connectors with the thinner wire is that those are the standard connector for a BEC, servo, or ESC in the RC industry and they are limited to the power that can go through the pins. More advanced users (many of which buy Castle products) can just chop off the connector and wire into whatever needs power through the BEC.

Always a good time watching your electrical tear downs. Cheers!

In real world usage, this BEC is used (and aimed) to power only the servos that control the various control surfaces of a model airplane (ailerons, elevator, rudder etc). It's not used to drive the main motor of the airplane. That means that it will probably never be maxed out in power draw if only maybe for a couple of seconds. And generally people that fly RC planes like myself we always use a BEC that can provide more power than all of the servos would require combined. Having said that this BEC wouldn't even get warm to the touch when in flight, even if you do crazy aerobatics with the plane which wouldnt last more than 10-15minutes of flight anyways before you need to land. So this is a good BEC and serves its purpose just fine.

As always, a thorough and thoroughly enjoyable video. Thanks a million!

Hey Dave. I'm one of Keith's aeromodeller friends and just wanted to let you know, YOU ROCK! Thank you so much for making this video. This was one of the most informative hobby-related things I've watched in quite a while :)

"This thing's cheap, it's like $38 or something which is apparently cheap for one of these things" Nope that's expensive af.

Awesome testing. As a big fan of Castle Creations products it's nice to see something they make put to the test. Pretty crazy how much a little airflow affects the temperature.

Awesome to see these on your'e channel. I bought a similar thing rated 8A, but the datasheet on the chip was only capable of 3. Ive also had one on my miniquad, that failed sending 14V through all the 5V electrics, ruining $100 worth of flight controller, receiver, camera and vtx.

thank you for this test. very excellent

Awesome to see a test

Cool vid. One of the more interesting ones I've watched in a while :-) Love the display on that B+K load. I have one of their bench multimeters (5491B) with a similar display, it's a joy to work with in a wide range of ambient lighting levels

Dave, thanks for looking at the Castle BEC Pro. I found it very useful indeed and confirms, for me at least, that Castle make good equipment.

When taking those thermal measurements, they should have been done with the PCB in the actual plastic case, as from my perspective, it obstructs the heatsink somewhat.

cool video Dave. loved it and the nice part that the test didn't bread the DUT. very cool.

I did model aircraft for a few years. Most of the models either have space behind the cowl for your speed control or regulator, or they have a largish hole there that feeds air into the plane with an exit hole near the tail. The mounting point for the electronics would always be in the airflow path. Also, you'd get far more than 5mph airflow there. After a long flight, my temp sensor would usually show the heat sink sitting around 60 to 62C.

Good video. Great insight. Notice the specs do not specify at what ambient temp.?

Nice one Dave, thanks! A friend of mine uses a BEC that looks very much the same heatsink in his aeroplane. As his systems engineer :-) I had him try a couple different geometries to mount the BEC in a "prototyping fixture" I jury rigged. Best performance so far has heatsink fins getting air "scooped" & directed over fins

Been re-watching some of Dave's old vids, geez they just are soooo good. Watched the 'Murphy U-Current 'one, and, well watch it! and if you don't remember from the first time, try and do your own detective work. Seriously brilliant.

Glad you actually tested this thing Dave. I fly rc planes, and there's so much false advertising when it comes to the electronics!

Thanks Dave!

I'm watching the video..., Dave talks about the temperature from the power dissipation of the heat sink and I'm like "huh. wouldn't it be great if he used a thermal imaging camera to evaluate this...". Then he pulls out a Flir E8 - something which i could only dream of with my PhD budget (we're currently "borrowing" a Flir i7 from another department - less spec) to show it on video.I wish I could subscribe twice! thanks for the quality vids Dave! great stuff! :P

thanks for doing this test. In the electronics category you are among the 10% best on UKposts. thanks for sharing. i watch many of your videos.

thanks Dave, for putting it through the tests that I can't do. sounds like it works OK, but needs lots of air to keep it cool!!!

Fantastic video, I learned a lot!

shouldn't you have put a fan on it? I would imagine in flight it would dissipate heat pretty well and it only has to last 30 minutes max.

It's interesting about the output connectors. Those are standard servo connectors and have been in use in rc for many many years. When they started being used the power handling requirements were a lot lower than they are today.

very good. with airflow and thermal image. and datasheets. do you have a servo to check for max current against rating when its blocked?

even so i flight helis and planes as well. but I never had the same curious though about all my BEC and speed controls like Dave is explained to us and I know that castle creation is one of the top brands out.

You should test more RC components like ESC's and things. That's what got me interested in electronics

That was very interesting! Dave, did you set your E8 to the correct epsilon factor? It can influence your temperature readingsby up to 10°C or more!

Dave, for further testing at all ranges you would need a Castle link USB adapter.

Joey Vann you are absolutely right!

Sweet, I think you confirmed that this BEC is pretty useful! Failing to hit the 15v current spec is disappointing but it looks like it can output 8A+ at all input voltages that it's rated for, and if you pull that continuously you just have to make sure you have airflow over it. Considering that most RC vehicles this would be in travel far faster than 5mph it shouldn't be hard to get that much airflow over it, and 8A is quite a lot for most applications (which probably peak at a lot less than 8A). Should be no surprise to RC people as Castle Creations are one of the big RC electronics manufacturers. Nice to have confirmation though!! Thanks!

sweet video, I've always wanted to know how close to spec they are! As others have said, castle are a big name brand. a long time ago they publicly stated that they were hesitant to put any ratings on anything because they would seem completely uncompetitive when compared with the absolutely insane and exaggerated ratings used by everyone in the rc industry. they started to add some ratings, that are still a fair bit lower than directly competitive products, but pretty much everyone knows they're more accurate. I think they even have a standard for what continuous means in the rc world. also in the manual it's stated that the little plugs are only rated to 5A each and to add more or different connectors if you need more current.

Great fan ! Used two Sunon Fans to make quiet a Dell 24 port Switch, but had to change the pins around. Also great is the EEVBlog multi-meter... Thank you for the video ! tjl

The logo on those two cap cans is the same one on the solid polymer caps I bought for a Radeon HD 5870 GPU card six years back. For the life of me, I can't remember the brand, but I remember it was a well-known name. For what it's worth, I only just retired that same GPU card last week and it still works.

Sometimes faulty BECs cause RC radio signal loss. Can you please have a look at the RF spectrum... :) Maybe use a LISN and show us the conducted emissions. :) Or some nearfeild probes and show us the noise band.

Im Watching Your videos from centroamerica good job Dave

I love your lab dave!! I work in a nice lab but don't have proper equipment for my at home lab! Just graduated and am trying to build a better lab!! slowly!

Castle is generally reguarded as the better quality BEC untis available out there. I see way too many guys bury them so they get inefficent air flow. The result is generally a brown out,this happends durning a manuver that requires more control surface imput,that inturn puts more of a load on the BEC,resulting in a brown out,loss of control and crash. Then its always blamed on servo's of course.I always use a ESC with a switching BEC seperate from the ESC so if the amp rating is drawing too much power,I dont lose power to my control surfaces.I havent experienced a problem since doing that. Even if my ESC goes up in smoke,I can still land my plane.

Mate your videos are ALWAYS longer than you thought they would be. :)

well done

Nice to see proper non goofed review of one of these... ;)

Those output caps are Chemi-Con PS_ series (not sure of the last letter, series name couldn't fit on the top there) solid polymer electrolytics - i wouldn't be concerned with those kicking the bucket anytime soon. Besides, their tops are even "outside" so they get some cooling from the airflow.

with high permeability ferrites curie temperatures can be as low 120°C so that can be a problem as well, ceramic capacitors also dont really like high temperatures as do electrolytics of course

Would be interesting also to see how much noise this dc-dc converter produces at these high currents.

I'm still watching so perhaps you address this later, but I'm pretty sure you're going to miss an important point that would be obvious to an RC person... wind! (Not your fault! You're an EE blog, not an RC blog...) When in use for its intended purpose (ie: model aircraft) the BEC can be subject to a quite fierce airflow, depending on placement. RC people regularly run equipment at power levels that would fail on the ground. Similar to the way professional cyclists sometimes overheat when they're on stationary bikes. An RC person who expected to run this "hot" would put it right in the propwash or even force some airflow through the fuselage. To replicate that, you'd need something like a leafblower. I'm impressed it went into thermal shutdown rather than just releasing it's magic smoke. In RC terms, that's basically "bulletproof". (Now if they could just make them tree-proof!) [edit] Five miles an hour? *giggle* Any plane that needs a BEC that big and is only going 5mph is probably a miniature model of the Spruce Goose. Your intuition towards the end that "with some good airflow this might work" was right on track. Model planes can go 60-100kph, which is the trick.

Castle speed controls (with built-in BEC) flawlessly power most of my RC trucks and helicopters. The same small piece of software from Castle (Castle-Link) lets me adjust parameters on all of them, allowing programming for almost any application or condition. As always, thanks for your unbiased reviews. Keep up the great work, and remember... Don't turn it on - Take it apart !!

This is over rated but giving Model aircraft dont draw constant current is actually really good , also planes and helicopters give some airflow since they are flying

Hi Dave, 48.9W is Power consumed by the BK Electronic Load, Regulator is producing 52.5W , Delta around 3W is the Joule effect produced in the cable , gone in heating the cables. on my point of view its not an error . you doing a great job ! Ali.

Great testing there Dave. Never thought to stress test my BECs this way as I have the same PSU and a Maynuo EL (which looks to be a ripoff of your BK unit). As many have said the Castle creations units are certainly one of the better brands out there for this sort of gear and they're not really expensive as you mentioned. I have a couple of those CC BECs but have never really stressed them - they are way over sized for even my large RC heli's. For reliability I've now removed the BECs and gone back to a dedicated control battery (2S Lipo). Some high performance servos and gyros ( for Heli's anyway) now directly run at the higher 7.4volts (as opposed to the traditional 5 volts) of a 2S battery so the BEC can be totally eliminated in my case. One less thing to go wrong IMO. Once again - great video.

The heatsink data sheet calls for a 1" square heatsink, 25x25mm. Now I'm not confident of the scaling, but the heatsink on the device looks significantly larger than that to me - between 30 and 40 mm square.

All your calculations I believe were based upon 20* ambient temperature. In a hotter climate like 40* or maybe 45* ambient I just wonder if the converter will hold its regulation. Just a thought

What was a best option for those Wet electrolytic capacitors for long time and reliability?

It would be most interesting to see the output on a scope under the various loads.

The caps were Nippon Chemicon PXE series.

7:48 It's Nippon Chemicon PXE series Conductive Polymer Capacitor

How can you get your timing right? You said that the video would be about 30 minutes and it turns out to be! nice!!

Anodized aluminum probably has a different emissivity than the default setting in your flir camera. Did you take that into account for your temperature measurement ?

Was liking the look of your Flir thermal imaging cam Dave, until I found the price!!! £4000 in the UK!! I suppose it was a freeby then! On using the voltage reg, presumably it would be mounted exposed to airflow created by prop wash? In which case, plenty of air flow!

Those output current maxes also aren't likely at all output voltages. It's got an adjustable output voltage. It might output 15A just not set to 6.5V

can we replace the aluminum heatsink with a copper one on this bec? how is it mounted?

I think the "continious" means 1 batteryload. most batteries only stand for about 10 minutes. when you change the battery its always reconommed to wait until the motor and speed controller are cooled down.

For anyone who does anything RC. Those twin output cables are designed for signal and power to servos.

Dave I love this test thanks. But I fly giant scale planes and RC heli. In the RC world we run these at max 6s because of its short comings also if we got 8 amps draw on our setup it's only for split second at time. Normal maybe couple amps. Great job.

as an RC guy I really like this video, was very understandable for an electronics noob :)

You may have mentioned this but typically no one ever pushes their electronics to the peak as what is listed on that BEC. Those numbers are all PEAK numbers,not actual rates your Equipment would be putting out. I am talking about running full throttle,cycling landing gear retracts,full navigation lighting,operating servos at full capacity,flaps fully extended or being retracted. Usually a failure occures just after take off or landing because of those reasons. Expect a Transmitter brownout before that BEC to fail though.

Video is 31 mins long and yet just minutes after upload and there is comments and upvotes and downvotes, geez people.

Hey Dave, I was wondering what the status of the uCurrent is. Did that issue with the assembler get solved? I was hoping to pick up one and I couldn't find it anywhere in stock. I could use a local pick and place fab but that would cost $300 for a batch of six when I only need one.

These are designed more for big helis running on 12s so on the higher input is wear they are most commonly used

3 amp is usually "higher spec" and safe from causing a reboot mid air for park flyers

Maybe the heat sink can be installed outside the fuselage ? Here you have a good air flow ;-)

also remember that its not always constant current in a rc plane or any rc really as servos dont always move and work hard constant

When are we going to see the FLIR teardown?

Should we consider the heat generated from direct sun light or it has nothing to do with our case !

Can you do a video about Lead Acid Battery desulphation devices. Do they really work?

I would like to know why there are two wires coming out with Servo ends?

If you could raise the output voltage from 6.5V to something more like 10V, it might very well be able to supply 15A. I wouldn't mind seeing more on this item if you find time :)

A few of those watts will also disappear in the wires, so the heatsink would probably dissipate about 15 watts.

Heat sink size/weight will always be compromise since it will affect performance and flight time of planes, copters and quads.

Can i just point out that the transistors is NOT what is going to cause thermal problems in a regulator like this!? Dave implies that the transistors will be the issue, but there is nearly no voltage across them when they are conducting, so also very low power dissipation. The diode is what will cause your thermal headache. Depending on duty cycle of cause, but often the diode dissipates much more power. That is one reason why synchronous rectification in DC-DC converters is so awesome.

That thing could have used a synchronous rectifier FET, would have cut losses in half if not more, especially at high voltages deltas where the free-wheeling diode/FET carries the bulk of load current during the 80+% off-time.

Assuming the temperature drop over the board I am actually surprised that it didn't burn.

Dave, Castle Creations makes some of the better reliable BEC units in the RC Industry. I wouldn't worry about the lifespan of the caps. Most likely the failure of the BEC would be due to a crash. :-)

castle bec screwed my hitec servo after running in wet, shouldn't it have any voltage protection so if it malfunction it shuts off and doesent fry other electronics connected to it ? ?

I fly electric heli's up to 90 size (250+ amps into the motors). I use this type of controller all the time and they are normally used to power radio and servo's etc that create short term peak loads rather than continuous maximum loads. If you want to run them at full power continuously then yes you need to put them in air flow and they work fine. In other words they work fine for the intended purpose.

it is intended for an airplane so there is going to be a lot of airflow to cool it. it is also good that it has an overtemp shutdown.

What about if it was running at 16 volts exactly instead of 15.2, would it manage to output 15 Amps or would the 0.8 Volts not be enough to cause a problem?

if i understood right this is for tricopters right? so ehen they fly there is air passing throught the heatsink. havent finished the video yet. just mentioned it in case you didt try bloeing a small fan on it in the next tests(after the first 160c "meltdown")

8:28 Incorrect, polymer capacitors have lifetime ratings all over the place, just like electrolytics. But yes, there are some large vent-less electrolytics out there. Specifically, the Sacon FZ series, which are known to go off like gunshots!

is this sort of protective glue in the component side intentional? if yes, why? humidity?

I think the ratings are nothing to do with the BEC output. A BEC is designed to run from the flight battery in an electric model that drives the motor, and provide a low voltage (typically 4.8v) to power the receiver and servos, which typically don't require a huge amount of current. Before BEC's came along, most people had to use a separate battery pack (often 4 x AA ni-cads) to power the receiver and servos. I doubt that a BEC would be expected to supply 8 amps or more !

cheap? castle is brand name in the rc world. A cheap bec is less than 10$ :)

That's why these have earned the nick-name 'Castle Cremations'.

Do take into account that this device is intended for use on an airplane/heli with plenty of airflow. If you're at max load and only going 5mph, something is really wrong. I think I would opt to operate it with the case off.

ohh.. its just a bec... 8amp would be massive for servos... prob way overspecced product... or for big planes. Normally the BEC is with the speed controller, that would be more interesting viewing, seeing if it can send 120 amp continous.. some of the old boys like nicd batteries for BECs. The new coreless servos often with their wide voltage op ranges can run straight off the lipo.. with good torque characteristics

The usual overstating of specs for most hobby products. What would help this survive is probably the fact that most of the load would come from the servos moving the control surfaces of the plane so only in short bursts as it maneuvers. Not much load when all the servos are neutral(eg flying straight).

Castle for the win! USA made right by me