Two digital servos and a CC BEC have gone into thin air.....
 

Yep, indeed.

After I've installed and combined a CC BEC, a Futaba Digital S9951 servo, a FASST receiver, a Tekin R1PRO, a NEU 1512/1.5D and a 1000MFD 35V capacitor together, the servo( and another one I've tried as an experiment) and the CC BEC were fried up abruptly.

I don't really know what've caused this. Although I've ordered the things again, I'm afraid the same issue might occur.

I've got to identify the problem and solve it befor it happens another time.

Please, guys, help me.....

Thanks,

Alawi El-Jifri :)

You did disable the R1Pro BEC, right?

Yeah, I did.

Guys, for real I did not open this thread to have a ten page chit chat( though I'd like to).

All I'm asking for is some help from the pros( Where in God's name are they??!!!).

AL

its hard to tell without a wiring diagrahm but I am guessing it is related to the BEC and the cap either or both were wired incorrectly...can you post a diagrahm ? when you programmed the BEC was it working ok?

I've read in another forum, that some of the digital servos can pull more then 5A at stall. The guy that mentioned went to say 10A, but I don't think the normal sized servos are there yet (I might be wrong as we have servos that can put out over 500oz/in http://www.servocity.com/html/hsr-59...ra_torque.html). In electronics though as I've learned from our great members here, the actual peak might be even more. You could also have a unit that was faulty. This things can and will happen to anybody. I've read report of BEC units failing.

I've also heard that when the CC BEC fails, it sends full battery voltage to the load instead of simply not working like most others do.,

thats not good.....maybe I will invest in a koolflight ......

Oh no.....

I've just ordered another CC BEC ( the one in the CRT.5 is working perfectly) and a low profile digital servo.

I think I'll need to use higher grade capacitor. Maybe a 2200mdf 25v ones.

Did anyone use such a capacitor with their R1Pro?

BTW, how can I program the BEC?

do you have a volt meter? check the bec output

That's why I still use Rx packs. It's been rock solid.

Yeah. I've never had any problems with rx packs.

The bec is no longer alive.

I smelled it.....mmmmm...full of bar bq.

you would use Castlelink and after you connect the castlelink to a USB port pull up the CC program and it should see the BEC and pull up that portion of the program

I use a CC BEC in my buggy with no issues so far, but plan to make a circuit to cut off power to it if the output goes too high. The KoolFlight or DimensionEngineering or Hercules BECs are great alternatives IMO; low/no noise, strong output, and good efficiency. Receiver packs obviously work well, but it's just one more thing to charge.

I have run with RX packs and BEC's and much prefer the BEC. RX packs are just a pain to use in my opinion. My koolflight bex works like a charm as BrianG stated and would have no reason to use anything else.

At the risk of pissing everyone off...let me just say that I have heard that the castle BEC is a micky mouse unit and I would not run my 100.00 dollar servos with it. Nor would I use the UBEC ( I have one right here that is fried). I run a 50.00 dollar unit called the HERCULES BEC you can get them from brian at tanicpacks (worth a look) he claims that the hercules bec is the best currently made. Sorry if I come off as abrasive I just never got the hang of suger coating.

:lol: I meant to say check the new set up and see what your current draw is.

Thanks for the info.

I had a friend that had the same failure on the cc bec two weeks ago. It put out 16V, no smell and it could still show on the castlelink to be at 6V.

Any BEC has the potential for failure. However, the CC one is the only one I know where it will pass full battery voltage on failure. Most others simply stop working.

The Hercules was designed and produced by a buddy of mine. He was my heli trainer actually. We worked together on a few things. I test and help with a few of their products. Jimmy likes to blow stuff up. He ragged me hard for having a castle bec in my buggy. He was telling me how easy it was to make them fail, but I only run a 94359 and it has been good.

The Hercules is a killer bec http://www.western-robotics.com/RCproducts.html
I was going to do all the soldering for them at one point (anything that doesn't go in the oven). I still remember when we started selling bec's and failsafes and the boards were hand cut and drilled LOL. man it's come a long way since then. He has about the same setup in his 2 car garage as does castle in their shop pics they showed a while back..... and he does stuff for Honda, Toyota and Sherline mills as well now.... all this from a guy that used to program robotics stuff and I talked him into making rc gear because he's a bloody genius

Ive had 2 CC BECs fail on me now. One went up in smoke, but did no other damage. The other took out a $100 servo and $90 Rx.

I was running a few of these cheap ones for a long time (years) prior to getting the CC BEC and have yet to have one fail. When the CC units died, these trusty fellows went back into service and I havent looked back. For $15 you can beat them.

http://www.helidirect.com/product_in...oducts_id=1158

I hate to link to outside stores, If Mike carried them I'd buy them from him.

I went on that same site this morning looking at the Hercules High voltage model...I was wondering if they are reliable

http://www.helidirect.com/product_in...oducts_id=4667

Don't get me wrong, I really like their products too. I have their ultra high V BEC and it tested very well. And it doesn't look chintzy either. It's just that the CC BEC is a really good BEC for the money (high output, efficient, and programmable)... if it doesn't fail. That's the only "gotcha" really; if it fails, it takes out your servos and receiver. At least you know what the problem is if the CC BEC fails -It's hard to miss smoking receiver and servos! :wink:

The trouble I've noticed with some of the cheaper UBECs out there is build quality, or rather component selection. Ever notice how the "good" BECs use fairly large inductors? If they are too small, they saturate too quickly with higher currents. Most of the switching BECs out there (aside from CC) use a switching regulator IC (sometimes the same one), so the selection of support components makes a big difference. Howewer, if running the cheaper BECs at lower currents, they aren't so bad.

Well I confess to accidently getting my series and parrallel leads mixed up (don't ask) - I put 10s a123 into my MM and cc ubec - no smoke no fire... Swapped back to 5s and all ok. Thank you RC-Monster!

Cant speak intelegently about any of that... but I can tell you I know they just work and have given me no problems at all even running high power digital steering and brake servos in my Savage.

Well, I think I'll go with either a hercules bec or a " Jhautz" one or even get both of them.

Man! You guys chimed in really cool. I couldn't ask for more.

Problem = A bec failure

Thank youuuuuuuuuuuuuuuuuuuuuu, dudes!!!

BrianG, I wonder if you could answer something, how many volts will a receiver/servo take before they cook? I have CC BEC that I have not run yet, partly because I am in debug mode still, and partly because of some of the failures I've read about.

I run 2S+2S, and I was thinking I'd run the CCBEC off one pack, my reasoning is that if the BEC did fail, that the radio gear might survive 8V. Thoughts?

I can run my leds and fans (eek!) off the other pack, for a somewhat balanced accessory load.

I think the answer to how many volts is to much is going to be different for different servos and recievers. I know that the Spektrum Rx will run up to 9.6V I believe and servos are rated for anywhere from 5v to 9v.

I have personally run my nitro buggy on a 2s li-ion pack (8.2v peaked) with no regulator and have had no issues at all. The servo is blazing fast at that voltage, but its still going with no problems. There may other servos and Rx that wont take that voltage. You will have to do some research on your specific equipment.

All that being said... I think you will have a much better chance of everything surviving a BEC failure running on 2s lipo vs 4s though so I dont se how it could be a bad thing with the exception of the pack that caries the BEC load will wear down quicker than the other pack so you will ahve to be carefull not to over discharge that pack.

I have a Spektrum, so that's good news, thanks jhautz.

I'll definetely take a potential pack to pack imbalance over a potential 2 hundred dollar bill for toasted radio bits.

As I said I'll be running about 10 leds and either 2 or 3 fans off the other pack, shouldn't be far off as I only have one 128 oz steering servo and one 80 oz shifter servo, and that's intermittent enough to where it doesn't really count much.

Are you sure about 9.6 on the receiver tho? That sounds way high......

Figure about 15mA per LED (up to 25mA for high brightness ones), and around 100mA per fan. That's 0.45A total being conservative (15mA X 10 LEDs and 100mA X 3 fans). Figure average of around 1A for both servos together (bursts will be higher). So, that's 1.45A.

If I were you, I'd put some of those LEDs in series. Each "string" will only take 15-25mA, so that's better right off. Depending on the battery voltage and brightness/color of the LED, you may only need two or three strings instead of 10 individual strings. Then, get the appropriate resistor for each string and tie them direct to your full battery pack.

Then, use 12v fans instead direct to the battery, maybe use a linear regulator configured for 13v if you're using higher than 4s. 12v fans use much less current than their 5v counterparts for a given airflow.

Both of these suggestions will remove the ~1/2A load from the BEC.

That's great info, 2S is cheap insurance there!

Brian I should have mentioned I'm using automotive style leds each with their own resistor, so I'll just be merging them all close to the resistors and use a single JST plug.

And yeah 9.6 on the RX, thanks for verifying jhautz. Good stuff to know.

Well, turns out my fear was not unfounded. CC BEC is history. I guess seeing how much smoke it could produce was worth the $25.......

Radio gear did survive, but somehow it managed to half-melt the insulation on the receiver lead of , my brand new MM, looks like my esc may have JUST survived. I am way more irked about that. I tested it multiple times with a meter, had it set at 6.2, the second it had an actual load on it, poof.

I don't know if it's even worth trying to get a refund. I'll eat the $25 knowing it'll never happen again cuz my experience with bec's ends here. So I'll be paying my LHS (2 hour round trip) a visit to buy a $3.49 4AA receiver 'pack'.

Joy.

When my CC BEC failed sometime ago, it took out my servos with it. But later, I found out why it fail. Its heat. The first one I fry was mounted next to my MM ESC...good source of heat there. One of my friend mount his in the same matter, and he fry his too. The second CC BEC I got, I mounted it where is not next to any source of heat and a location where air and pass over it...and no problem since...knock on wood.

Has anyone with a failed CC BEC did any digging to find out which component blew? During my testing, the inductor was the hottest part at full load. I wonder if the lamination are simply melting? If so, a larger inductor (physically, not inductance value) may be the way to go. I still don't like how the CC BEC goes though - I think a UBEC should simply output 0v instead of full battery voltage...