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Old 05-30-2013, 10:12 PM   #1
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Default how do i know if i need a new servo and a bec??

So i did some upgrades to my ax10.
Novak rooster esc
Pitbull tires 2.2
7 cell battery on front axle
Stock servo no bec and stock receiver. I'm new to doing this stuff by myself. I had a friend that used to help me out but I moved away. Please help me.
Problem is after i put this new stuff on, I go 10 feet crawl over something and my truck dies, won't turn.... Is the esc bad? Do I need a stronger servo? Do i have to get an external bec? If so how do I install the bec? Thanks for the help!
[IMG][/IMG][IMG][/IMG][IMG][/IMG][IMG][/IMG]
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Old 05-31-2013, 01:45 AM   #2
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Default Re: how do i know if i need a new servo and a bec??

Is it just the servo that dies or does the whole truck die?
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Old 05-31-2013, 03:23 AM   #3
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Default Re: how do i know if i need a new servo and a bec??

Quote:
Originally Posted by wheelyking4x4x4 View Post
Is it just the servo that dies or does the whole truck die?
Seems like the esc gets drained or something then powers back up can go a couple feet then again no workie...
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Old 05-31-2013, 04:29 AM   #4
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Default Re: how do i know if i need a new servo and a bec??

Sounds like a battery if the ESC seems drained.
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Old 05-31-2013, 06:21 AM   #5
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Default Re: how do i know if i need a new servo and a bec??

If you unplug the servo can you drive further?
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Old 05-31-2013, 06:44 AM   #6
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Default Re: how do i know if i need a new servo and a bec??

Does the ESC have an adjustable LVC?

Could also be that your stick pack has taken a dump. Or the charger for that matter.
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Old 05-31-2013, 06:58 AM   #7
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Default Re: how do i know if i need a new servo and a bec??

Quote:
Originally Posted by Willyb211 View Post
[IMG][/IMG]
What are these crimp connectors for?

I would be suspect of any crimped on connectors. Don't get me wrong,
I use Automotive terminals on my rigs, but I solder them on. I would
also suggest avoiding splices like this, even soldered ones. every
connection point adds resistance to the electrical system, solder
connections are better but you are still adding resistance. the
fewer the connection points the better off you are. this also aids
in trouble shooting later on in that you have less possible fail points
to check.

I can't see what battery connection you are using, but I have seen
the cheaper toy grade style (is it the tyco?) fail randomly and produce
the same symptoms you describe. you say it happens when you roll
over a obstacle, it could be shaking the connections loose if they are
at all shady.


I would also suggest getting away from that 7 cell battery, you can
pick up a couple small capacity Lipos and a cheap smart charger for
less than $30 shipped on Hobbyking.com. chances are that the battery
is worn out, it shows a full charge but when you put a load on it fails.
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Old 05-31-2013, 07:17 AM   #8
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Default Re: how do i know if i need a new servo and a bec??

Quote:
Originally Posted by Docwolf View Post
... the fewer the connection points the better off you are. this also aids in trouble shooting later on...
I think having MORE connection points help trouble shooting, because it makes it easier to remove the individual parts:

Here I can disconnect any one part at a time without using any tools! Try doing that with everything soldered together...
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Old 05-31-2013, 08:53 AM   #9
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Default Re: how do i know if i need a new servo and a bec??

So the Battery is new it is a Trinity 7-Cell EP4600mah nimh Zapped Sport Battery with Traxxas Female Connector, The Crims are for the ESC to Traxxas Male Connector.
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Old 05-31-2013, 08:54 AM   #10
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Default Re: how do i know if i need a new servo and a bec??

[QUOTE=Maxx_Savage;4344125]Does the ESC have an adjustable LVC?

What is that?
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Old 05-31-2013, 08:56 AM   #11
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Default Re: how do i know if i need a new servo and a bec??

Quote:
Originally Posted by nigels_world View Post
If you unplug the servo can you drive further?
If I unplug servo It works Fine just doesn't turn but then I will plug it back in turn back and forth a few times esc light goes dim and doesnt want to work wait 10-15 seconds all fine or unplug then plug in works.
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Old 05-31-2013, 10:32 AM   #12
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Default Re: how do i know if i need a new servo and a bec??

Sounds like the stock servo is having issues turning those new sticky tires. Does the servo get warm? It'll draw more amps if it's tired & getting warm, causing a brown out. A BEC wouldn't hurt, but ultimately if the servo is getting weak then a new one would be a fix. I think a new, stronger servo and BEC is in your future.
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Old 05-31-2013, 11:14 AM   #13
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Default Re: how do i know if i need a new servo and a bec??

Quote:
Originally Posted by Devil Inc View Post
Sounds like the stock servo is having issues turning those new sticky tires. Does the servo get warm? It'll draw more amps if it's tired & getting warm, causing a brown out. A BEC wouldn't hurt, but ultimately if the servo is getting weak then a new one would be a fix. I think a new, stronger servo and BEC is in your future.
Is it hard to install a bec? Can you point me into the direction of a video on how to do it. Which bec would you all recommend?
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Old 05-31-2013, 11:40 AM   #14
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Default Re: how do i know if i need a new servo and a bec??

plenty vids on youtube but try a guy called squirrelod on there and i think most people would recommened the castle creations 10a or even the 25a pro bec try ebay for that

https://www.youtube.com/results?sear...be.mx3OaKacODo
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Old 05-31-2013, 11:45 AM   #15
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Default Re: how do i know if i need a new servo and a bec??

Quote:
Originally Posted by Willyb211 View Post
If I unplug servo It works Fine just doesn't turn but then I will plug it back in turn back and forth a few times esc light goes dim and doesnt want to work wait 10-15 seconds all fine or unplug then plug in works.
Sounds to me like you're overheating the internal BEC and suffering 'brown-out'. When mine was doing that, I pulled out the red from the ESC's receiver connection and ran a separate battery into the receiver. Since that worked fine, it was obvious I needed a BEC. Been smooth sailin' since I put one on.

Now, the battery I was using for testing was one of my 2S Heli LiPos, so I know the receiver and servo can withstand 8.4 volts for a short time, but I wouldn't wire them direct like that. And taking another page from the idiot diaries, when I put my BEC in, I set the voltage to 7.0 volts, and within a few comps managed to completely burn out the servo. Servo temps were well over 210° on a regular basis. I wouldn't go be beyond 6.0 volts on a stock servo.

I agree, though, start saving up for a BEC and servo.
Some vendors on here have been known to set the voltage for you before shipping your CC BEC, if you ask nicely. Then you maybe could get by without a CastleLink.
And the servo I went with in my comp crawler is Futaba's S3051HV. Rather weak, but it handles 7.4 volts without heating up, and is only $40. The trail truck still runs the stock servo and 6.0 volts.
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Old 05-31-2013, 12:14 PM   #16
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Default Re: how do i know if i need a new servo and a bec??

That's a whole lot of tire for a stock servo. I tried a few cheaper servos trying to save some money, but in the end a Hitec 7954SH with my CC BEC set @ 7.4 does what I want it to, and that is with 1.9 PBs. I used a Hyperion that was supposed to be over 300oz but it would stall as easy as the stock axial with no BEC.
So the short answer is yes, you need a BEC. Heyok sells a plug and play version that would be the easiest way to go and RC4WD has the E-Tap E-Tap BEC/Lighting Tap For Deans Ultra Plug with JST Plug that would only require putting a JST plug on the BEC. My recommendation is buy once cry once. A lot of hobby shops will program the BEC for you. My LHS has even programmed my ESC even though I didn't buy it there. They have a castle link hooked up and ready to go.
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Old 05-31-2013, 10:59 PM   #17
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Default Re: how do i know if i need a new servo and a bec??

Assuming you have a regular rooster and not a super

http://www.teamnovak.com/download/in...ter_superr.pdf

then the spec for the internal BEC is

BEC Voltage 5.7 volts DC
BEC Current 0.5 amps

0.5 amps is barely enough to run the RX. So I would say you definitely need an external BEC. If you have $20-25 the everyone seems to like the CC BEC

Castle Creations | CC BEC and CC BEC Pro

It comes stock programmed at 5.1v and that is safe and will work if you can't get it programmed. If you can get it programmed to 6v then you will get a bit more torque (turning ability) and speed from your servo but assuming you will wire it the standard way you should check that your RX can be run at 6v before you do that.

If you just want something cheaper to get you going, a switching BEC that can deliver 3A at 5v or 6v can be had for less than $10 and should work fine with your stock servo and many others. Here's an example of this kind of BEC. This is not a recommendation. I have no experience with this product

AEO 6V 3A UBEC

With this you might have trouble with very high torque servos say > 300oz but if you are in the marked for $100 servo then you should get the CC BEC first.

The stock servo could be an as-2 or as-3. The As-2 is either 80 oz/inch (5.7 Kg/cm) 130 oz/inch (9.3Kg/cm) at 6v depending who you believe (some claim it is a re-branded Futaba S3010 Axial AS-2 High Torque Digital Servo SCX10 AX10 Rock Crawler Futaba S3010). The AS-3 is supposed to be around 130oz/inch (9.3Kg/cm).

80oz/in is definatly wimpy particularly if those tires are grippy and you may want to look for something better soon. 130oz/in is not huge but should get you around for a while.

BECs are not hard to wire but there are a couple of choices.

The standard way is to power the RX with the BEC and let the servos get their power from the RX. The BEC voltage output should not exceed what your RX uses (generally 5v or 6v - it seems that 6v is safe for most modern RXs but really you should check your RX to be sure) To do this you must disconnect the ESC BEC from the RX (red middle wire).

The more advanced way is to use the BEC to power just the servo(s) which allows you to use servos that can run a higher voltages than the RX. This has been described numerous times here so you can search for how if you end up with a higher voltage servo.

In any case you should position the BEC away from the RX since it can cause interference.
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Old 05-31-2013, 11:11 PM   #18
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Default Re: how do i know if i need a new servo and a bec??

Grabbing a new servo and bec is your best option. You could run a rechargeable rx pack from nitro rc's in a pinch to get you by (don't forget to pull the red wire from the esc), but it's a pain needing to charge 2 packs to run. When you have the cash, grab a bec then servo later.
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Old 06-01-2013, 07:43 AM   #19
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Default Re: how do i know if i need a new servo and a bec??

Well I will be getting a new servo and a BEC next week From my Hobby shop they will be sddering,installing and programing for free. Will update after my new parts are in. Thanks all for the input!!
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Old 06-01-2013, 07:51 AM   #20
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Default Re: how do i know if i need a new servo and a bec??

Quote:
Originally Posted by Olle P View Post
I think having MORE connection points help trouble shooting, because it makes it easier to remove the individual parts:
Here I can disconnect any one part at a time without using any tools! Try doing that with everything soldered together...
Just more points for failure imho. I'm in the "only plug you should have is the battery connector" club.
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