Set-up without connecting the main battery

[alistair.howie]

Hi there.

As a complete Newbie, I'm coming to grips with my new Trex 550e and have picked up some snippets online about how to set-up the servos, swash, etc without connecting the main battery but rather using a separate 4.8V, 1100mAh NiCd 4 cell receiver battery as the power source. Being completely new, this appeals to me for obvious safety reasons!

Can someone please explain what connects to what and with what connections? I think some form of Y-harness/extension lead is suggested, which is tucked out of the way when powering/flying the helicopter using the main flight battery. But when it comes to set up, that lead is pulled out of the helicopter and plugged into the dedicated receiver battery. The advantage with this approach, it seems, is that I don't have to disconnect two of the (apparently fragile) motor connections to remain safe.

However, I'm afraid I've confused myself with ESC connections, receiver connections, what goes where/to which terminal, what type of harness to use, whether male/female ends (JST?), etc. Also, is this even a good idea? Seems so to me, but would be very grateful for advice.

Thanks!

[waveydavey]

The battery connector which will be a standard Jr or Futaba type will connect to your receiver where it says Bat. Thats it, bind your rx and then do your setup. Are you saying that you will use the battery then for flight or will you use a BEC from your main flight pack? IE the nicad is just for setup

[alistair.howie]

Thanks for the reply. The NiCad would just be for set-up.

What your reply has just highlighted is that I actually haven't got much of a clue about how my wiring should be set-up. And I complicated things further by decideding I wanted FBL from the outset, with a v bar blueline 5.0 express!

Looking at this Trex 600 wiring diagram http://myhobbies.ca/?cat=69 (second from the bottom of the page), and ignoring the FBL electronics for a second, what would be different about my 550e wiring? I have no receiver battery, so does my flight battery connect per this diagram into the throttle terminal on the receiver? I guess so, which is why you are saying for set-up, I just connect a receiver battery directly into the battery connection, right? So depending on length of wires and receiver placement, I don't need any y-harness, perhaps just an extension wire for easy connection, which I then tuck away during flight?

Is that right? And is this a good idea?

[waveydavey]

You won't leave the harness in place. I presume you will be using an ESC with built in BEC which means that the supply for your flight electronics will be coming from your flightpack. I'm not sure what advantage this would give you, with this method he has removed the supply from the ESC to his receiver and used a separate RX supply.

[millerman]

Complete newby with a 550e /0) I take it you have flown b4 ??


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[alistair.howie]

Yes, I'd be using the stock Align ESC with internal BEC.

I was just thinking that leaving the wire in place saves having to plug/unplug each time - easier to just tuck it away inside?

But I guess that only works if my assumption about how the wiring works is correct? Does the main flight battery connect via the ESC/BEC to the throttle connection, or the battery connection on the receiver? ie how would my wiring look compared to the Trex 600 wiring in the diagram I linked to?

Thx

[alistair.howie]

Yes, had some lessons on Trex 600 and been all over Phoenix for the past 6 months. Don't worry, am not intending to fly the 500e until I know how to fly. No desire to throw away cash any more than necessary. Will continue with the lessons and have my build and connections all checked out before actually flying my own aircraft!

[waveydavey]

Yes, I'd be using the stock Align ESC with internal BEC.

I was just thinking that leaving the wire in place saves having to plug/unplug each time - easier to just tuck it away inside?

But I guess that only works if my assumption about how the wiring works is correct? Does the main flight battery connect via the ESC/BEC to the throttle connection, or the battery connection on the receiver? ie how would my wiring look compared to the Trex 600 wiring in the diagram I linked to?

Thx

If you used the circuit in the drawing you wouldn't be using the bec to supply the RX. He removed the supply from the bec and added an rx pack. I don't think this gives any advantage really, maybe sap a little less power from the flightpack. You could leave it connected permanently but I wouldn't bother.

[alistair.howie]

So, to be clear (sorry I'm being thick here), ...

If you have a receiver battery, it connects, not surprisingly, to the battery port on the receiver.

If, however, you have a main flight pack battery instead as your only source of power, that connects to the throttle port on the receiver via an ESC (in my case with an inbuilt BEC)?

Is that correct?

[waveydavey]

Yes, because the signal part of the lead is the throttle input to the ESC. JR would be the :

orange (signal)
Brown (-ve)
Red (+ve)

Futaba/Align

White (Signal)
Black (-ve)
Red (+ve)

[Kozmyk]

It appears to have become common to use the term "BEC" instead of "Regulator".
It's understandable I suppose as in practice it is often the same device but used in a different configuration.
I must admit that it DID grate with my sense of logic also.

Strictly speaking it's only a Battery Eliminator Circuit when it connected to the Flight Battery and doing away with the Rx Battery. The same device when fed by an Rx Battery is being a Regulator.

To me, having a separate Rx Battery only makes sense on High Voltage 8s, 10s, 12s setups, unless the current drain from a particular servo system is too high for the ESC's internal BEC.

[alistair.howie]

OK, great, thanks. I'm getting there slowly!

So, is what I suggested at the beginning of this thread a common practice/good idea i.e. connecting a separate receiver battery to do the set-up and keeping hte main battery unplugged, a sensible thing to do?

What do most others do, just work with the main flight battery but just disconnect the motor wires?

[millerman]

Yes, had some lessons on Trex 600 and been all over Phoenix for the past 6 months. Don't worry, am not intending to fly the 500e until I know how to fly. No desire to throw away cash any more than necessary. Will continue with the lessons and have my build and connections all checked out before actually flying my own aircraft!

thats cool or would have been expensive and potentially dangerious way to get into the hobby but good on ya for having lessons and phoenix hope you enjoy the 550 when your ready its a nice heli to fly

[waveydavey]

OK, great, thanks. I'm getting there slowly!

So, is what I suggested at the beginning of this thread a common practice/good idea i.e. connecting a separate receiver battery to do the set-up and keeping hte main battery unplugged, a sensible thing to do?

What do most others do, just work with the main flight battery but just disconnect the motor wires?

Your suggestion of using a separate pack for setup is fine. Then switch to the accepted way of doing it with the flightpack and the built in BEC when your built and flying. You are aware on a separate note that the 550 is a bit of a beast aren't you. What fbl system did you go with?

[Vic.P]

If you want to do the set-up safely then an alternative to messing about with a different power supply would be to remove the blades and move the motor on it's mount so that the motors pinion gear is not enguaged with the main gear. This way you will be able to use the flight pack and set up the ESC at the same time and depending on the TX-Rx type and make, do the fale safe settings as well.
You will at some point have to do it this way to set up the ESC so you may as well do them together at the start and save yourself the bother of plugging in and unplugging leads on the reciever which can be a right PITA.