ESC BEC Help?

[mark381]

Hi, I am in the process of sorting out the electrics for my new Losi 8, I have a Mamba Monster esc with 2200kV motor, Futaba 3PM-MX 2.4GHz radio with R603FS receiver, Savox 1256 steering servo (Digital Coreless Motor). I wired up the electrics today to try them out and ran them using a 3s 2500mah 20C lipo (none of the components were under load and the esc was set to auto detect). I will be using a 4s 4500mah 30C battery in the car when it arrives.

I bound the Tx and Rx, then calibrated the esc, the motor worked fine (throttle reversed as per instructions), but when I used the steering servo, the movement was slow and jerky, when it went to return, the red light came on on the Rx indicating it had lost its bind and the motor twitched, it then regained it and returned to the normal position, this was tried several times with the same result (using both PPM and HRS modes), an analogue servo was tried in PPM mode and was found to work normally.

The instructions that came with the Radio said the Rx required 6V input, the instructions for the esc says that the output to the Rx is 5v and it does not appear to be changeable through the computer interface.

Has anyone else experienced this problem, my solution at the moment is to run a receiver battery pack (6V), hopefully there will be space somewhere under the car body. Other possible solutions would be a separate BEC, does anyone use these, any recommendations on make and model? the final option would be a servo with lower current drain, most likely analogue what type do people use? Alternatively does anyone else have any other suggestions for a solution?

Regards

Mark

[Vorza]

I had the same issue with the 1256, i found that a cap didn't cure it, therefore i installed a dedicated BEC by castle (CC BEC) which is great, you can configure the output volts and it supports input upto 25 volts, so i soldered it directly to the battery terminals on the esc and fitted a plug to it. strangely the 1258 worked fine although the specifications from savox are the same. note: if adding a bec you need to disconnect the positive wire from the esc.

HTH

[cbr6fs]

Can't you adjust the BEC voltage (using castlelink) on the Monster?

You can on the Pro, i have mine set to 6v

To be honest though after trying a BEC in my crawler i was THAT impressed i installed one in me Blitz.

Fitting a decent BEC is like going up a few levels in servo torque and speed

[mark381]

Vorza,thanks for the photos,really helpful, did not realise the CC BEC was so small, so will lend itself to a simple and neat installation. Where did you get yours from? Also does the Castlelink adaptor that comes with the Mamba Monster fit the BEC so that the voltage can be adjusted?

CB6FS thanks for your response, I looked at the castlelink software, but the Mamba Monster setup section does not appear to give you the option of increasing the BEC voltage and the instructions say its set at 5V, which seems a little low for an esc designed for a 1/8 vehicle that will be using high torque servos (and high current), maybe there will be a software/firmware fix, but in the meantime I think I will look at getting a CC BEC.

Thanks all and Merry Xmas

Mark

[Vorza]

No worries, I got mine from my local hobby shop, gave them the part number (010-0004-00) and they got one in about two days later. it costs £20.

Yes, you use the same castle link device and software to program the CC BEC as you do the ESC.

Happy Xmas mate

Edited December 25, 2010 by Vorza

[mark381]

Does the CC Bec automatically detect the number of cells the car is running on or does this have to be set using the Castlelink as well as the voltage to the rx? Also does anyone know what the current draw of a Savox 1256 is and what servos are others using for steering?

Regards

Mark

[cbr6fs]

Does the CC Bec automatically detect the number of cells the car is running on or does this have to be set using the Castlelink as well as the voltage to the rx? Also does anyone know what the current draw of a Savox 1256 is and what servos are others using for steering?

Regards

Mark

The CC BEC comes configured at 5v, you need to use castlelink to adjust it

[Vorza]

Does the CC Bec automatically detect the number of cells the car is running on or does this have to be set using the Castlelink as well as the voltage to the rx? Also does anyone know what the current draw of a Savox 1256 is and what servos are others using for steering?

Regards

Mark

Hi Mark

On the input side it can be up to and including 25 volts, you don't need to configure anything on the input side, as posted above you use castle link to raise the output to 6v.

Savox's pdf data sheet for the 1256 states the following when using 6 volt input to the servo;

Running current (at no load) = 120 mA

Stall current (at locked) = 5000 mA

Idle current (at stopped) = 5 mA

Therefore I reckon it can draw up to 5 amp

Cheers

[jony nitro]

When you use the CC BEC the blue, you dont use the internal bec as you pull the Red esc wire out.

[mark381]

Thanks for all the input, I know where i'm going with this now, seems a little disappointing though that the esc which is designed for a 1/8th buggy cannot power the receiver and a suitable single servo through its on board bec though.

I have seen it mentioned that capacitors can be used to 'stabilise' the voltage, could the SPM1600 Spektrum Receiver Voltage Capacitor be used on Futaba gear and would it be effective or would I be better off going with a BEC?

Regards

Mark

Edited December 26, 2010 by mark381

[Vorza]

I tried the power cap first, exact same one, it helped but didn't cure it. that power cap can be used with any receiver, it's just a capacitor.

Lee

[windsurfingman]

Vorza, how exactly do you connect up the BEC? I'm guessing that the two input leads are soldered to the ESC batt leads (to share the battery voltage between ESC and BEC) and the BEC output plugs straight in to the batt connector slot on the receiver? Then remove the positive ESC receiver output wire right?

I spoke to the guys at Modelsport, they had no idea and started going on about un-balancing the lipo cells.

Also, Hobbyking / Ebay do some cheap BECs - about

[cbr6fs]

Vorza, how exactly do you connect up the BEC? I'm guessing that the two input leads are soldered to the ESC batt leads (to share the battery voltage between ESC and BEC) and the BEC output plugs straight in to the batt connector slot on the receiver? Then remove the positive ESC receiver output wire right?

I spoke to the guys at Modelsport, they had no idea and started going on about un-balancing the lipo cells.

Also, Hobbyking / Ebay do some cheap BECs - about

[mark381]

Hi, this is the wiring diagram from Castle Creations web site, slightly different to the method used by CB6FS, this one uses the BEC to power the receiver and servo. I think this will help in my case as I want to up the rx voltage to 6V from the 5V supplied by the esc BEC, as well as having the ability to provide a constant 5A supply for the servo, not sure how many amps the on board BEC can supply from the esc.

CB6FS did you solder the wires from the BEC to the servo or get a male-male connector? I had not considered wiring it the way your diagram showed.

Regards

Mark

[Vorza]

Vorza, how exactly do you connect up the BEC? I'm guessing that the two input leads are soldered to the ESC batt leads (to share the battery voltage between ESC and BEC) and the BEC output plugs straight in to the batt connector slot on the receiver? Then remove the positive ESC receiver output wire right?

You pretty much have guessed it right, I soldered two wires, positive and negative, to the board inside the ESC, exactly the same place as where the leads are soldered to the ESC board that the main batteries plug into, i then soldered a small EC3 device connector to these new leads. this way it is simplified as i use two main batteries so power for the BEC is taken from both, the same as the ESC, it also simplifies the wiring as the wires don't have to trail from the batteries.

The other part of the EC3 connector is soldered to the input wires of the BEC, this way i can simply unplug the BEC and remove it, to use it in another car for example. also i have some LIFE RX batteries with small EC3 connectors on, so if i want i can plug the BEC into one of them and not power the BEC from the main batteries, this can be handy for long nitro finals as the main battery will last a little longer if it isn't powering the RX and servo.

I didn't remove the positive wire from the ESC lead, instead i plug the ESC lead into a "Y" harness and removed the positive wire from that, the reason being that if you disconnect the positive from the ESC lead, you can't program the ESC using the castle link, my way i simply unplug the ESC lead from the "Y" harness, plug the castle link into the ESC lead and then can program it.

I spoke to the guys at Modelsport, they had no idea and started going on about un-balancing the lipo cells.

The way i have it above won't unbalance the cells any more than normal usage could, because it is soldered at the ESC it takes power from all batteries the same as the ESC does.

Also, Hobbyking / Ebay do some cheap BECs - about

[Vorza]

Hi, this is the wiring diagram from Castle Creations web site, slightly different to the method used by CB6FS, this one uses the BEC to power the receiver and servo. I think this will help in my case as I want to up the rx voltage to 6V from the 5V supplied by the esc BEC, as well as having the ability to provide a constant 5A supply for the servo, not sure how many amps the on board BEC can supply from the esc.

CB6FS did you solder the wires from the BEC to the servo or get a male-male connector? I had not considered wiring it the way your diagram showed.

Regards

Mark

Hi Mark

Essentially the same as i did mine, i just connected the BEC input to the ESC end of the wire not the plug end of the wire, i then inserted a "Y" harness between the original ESC lead and the receiver and disconnected the positive from that lead instead of the ESC lead, this way the ESC can still be programmed.

In fact; if you look at the first and second pictures i posted, you'll see that the two wires coming out of the receiver box are the two ends of the "Y" harness, the added benefit to this is that i can simply unplug the ESC lead outside of the receiver box and plug the castle link lead into it to program it, no need to open the receiver box. also, if desired; i can unplug the CC BEC and plug the ESC lead into that socket if i want to power everything from the ESC's BEC, again there's no need to open the receiver.

The output amps of the castle ESC BEC can be as low as 2.5 amps, nowhere near enough.

Cheers

[windsurfingman]

Top advice chaps - it's saved me buying a recevier pack (which probably wouldn't havit fit under the Hyper 7 shell anyway) and would have cocked up the balance.

Thanks

[Krimz88]

Hi,

 

I am about to upgrade my Vorza to have the following:

 

- spektrum srs4210 avc receiver

- Savox 1258 Servo

- Castle BEC

 

 I know to run the above I need to install a dedicated BEC. My issue is that I can not for the life of me seem to work out how to gain access to the ESC to splice/solderdirectly to the battery terminals on the

esc? 

 

I found the image below in a post, but could not see how they gained access or had enough space to solder.

 

Advice would be much appreciated 

[Noj]

Look at the installation diagram, you'll see that the positive and negative wires from the BEC are soldered onto the ESC wires at the connector. They are fiddly to solder in, a set of helping hands makes life easier.

[Tamiyacowboy]

in that picture above. 

 

the ESC has been pulled out and the BEC wires soldered to the board with the main battery wires.

so they are more out of the way, in quadcopters, we will make a Y harness to feed the esc and also the bec unit.

you can do the same with your car, making a battery Y harness, plugging the esc and bec into the  twin tails, and the single tail goes direct to your battery.