600 Separate Rx Battery system configuration / TREX 550E DFC

[Bruno]

I posted a similar question in my earlier thread. However, I am failing to get information to assist me with HOW TO CONNECT/INSTALL a separate power source for my servos and BEAST X receiver.

I am interested with eliminating the potential of a failed CC PRO BEC frying my electronics.

Questions:

1) What resources are available for the wiring of such a system?

2) Am I over protecting (over thinking) my system? Is the likelihood of a failed CC PRO BEC low?

 

[Tony]

Actually your question was answered, it's just buried within the posts. The item you posted will work, but with the AR7200bx, the instant it loses power, it has to reinitialize. This can take up to 30 seconds or more since the helicopter will not be still in the air, it will be moving. Since it's moving, it will not initialize so it will fall to the earth like a rock anyway.

Just get an Align 2in1 or a 1900mah LiFe batter if your servos can handle the voltage. Make sure to charge the battery every third flight or so and you should be fine.

 

[Bruno]

Actually your question was answered, it's just buried within the posts. The item you posted will work, but with the AR7200bx, the instant it loses power, it has to reinitialize. This can take up to 30 seconds or more since the helicopter will not be still in the air, it will be moving. Since it's moving, it will not initialize so it will fall to the earth like a rock anyway.

Just get an Align 2in1 or a 1900mah LiFe batter if your servos can handle the voltage. Make sure to charge the battery every third flight or so and you should be fine.

Tony, thanks. I think you mentioned simply plugging in the 1900mah LiFe into the receiver. I am confused as to how the receiver will utilize the 1900mah instead of the 5300mah (main Battery) when the BEC fails.

In Other words, how do I prevent the electronics from frying during a BEC failure, despite the Rx re-initialization period.?

I apologize for my ignorance but I have enjoyed this hobby based on information from this forum and other sources.

Simply don'y want to risk frying $300 to $500 in electronics.

 

[Tony]

If you are that worried about the ESC's internal BEC failing, then get an OPTO ESC with no BEC and only run the LiFe battery. You don't want to run both, only one. If it was me, I would either stick with what you have, or get a new ESC and separate Rx battery. On my 600 nitro, I'm running the Align 2in1 with a lipo battery and that's it. I have no worries of anything failing and if it does, then I'm replacing parts.

IMO, I would never run a castle ESC on any aircraft. Way too many failures and fires resulting from them. But, I'm flying nitro in my large heli, so I have no idea what other ESC's are out there.

 

[Bruno]

If you are that worried about the ESC's internal BEC failing, then get an OPTO ESC with no BEC and only run the LiFe battery. You don't want to run both, only one. If it was me, I would either stick with what you have, or get a new ESC and separate Rx battery. On my 600 nitro, I'm running the Align 2in1 with a lipo battery and that's it. I have no worries of anything failing and if it does, then I'm replacing parts.

IMO, I would never run a castle ESC on any aircraft. Way too many failures and fires resulting from them. But, I'm flying nitro in my large heli, so I have no idea what other ESC's are out there.

I am using a Castle Talon 90 with an independent Castle PRO BEC.

 

[pvolcko]

It can be done, but IMO it is overkill. Granted, I've never suffered a BEC failure (or heard of one happening locally) so I may be biased against jumping through those kinds of hoops. With the CC BEC Pro the big thing is to make sure it is hooked up to a maximum of 6 cells (7S in a 14S setup). If you have a 12S setup then you should have the BEC tapped into just the first pack in the series. This will allow allow the BEC Pro to produce the largest continuous current and reduce the potential for failure. With these units the research I've done has indicated many (most?) of the failures that have occurred have happened when they were being fed 12s-14s voltage and were powering high current demand HV servo setups. When fed 12S voltage, the BEC PRo has to step down the voltage a significant amount, and in doing so cannot deliver high continuous current. By using 6S to power it you reduce the step down and it can deliver higher currents.

 

[Bruno]

It can be done, but IMO it is overkill. Granted, I've never suffered a BEC failure (or heard of one happening locally) so I may be biased against jumping through those kinds of hoops. With the CC BEC Pro the big thing is to make sure it is hooked up to a maximum of 6 cells (7S in a 14S setup). If you have a 12S setup then you should have the BEC tapped into just the first pack in the series. This will allow allow the BEC Pro to produce the largest continuous current and reduce the potential for failure. With these units the research I've done has indicated many (most?) of the failures that have occurred have happened when they were being fed 12s-14s voltage and were powering high current demand HV servo setups. When fed 12S voltage, the BEC PRo has to step down the voltage a significant amount, and in doing so cannot deliver high continuous current. By using 6S to power it you reduce the step down and it can deliver higher currents.

I am using 6S. Thanks. Puts me at ease with potential fried electronics. Perhaps my readings regarding use of independent electronic power was with set-ups without a BEC.

 

[Lee]

I have been using the CC PRO BEC for a long time with no issues on my 8S 600. I was using the internal BEC on my Phoenixtech ESC for a year before that when it was on 6S.
I wouldn't worry about it. Just use the CC PRO and fly

 

[Bruno]

Looking for clarification/confirmation:
Is it correct to say; once the BEC is eliminated and red wire disconnected on the ESC and a separate LiFe servo pack is connected to the RX, the BX RX will draw power for the servos from the LiFe RX pack and the ESC will draw power just for the motor from the battery (not send any power to the RX) and ESC is controlled through the RX?

 

[pvolcko]

Yes. You used "BX" in there. If you're using a 7200BX FBL controller/Rx combo unit, make sure it can handle the voltage of a direct connected life battery pack (6.6v-7.2v for a 2S pack). I was under the impression it is not "high voltage" compatible. But it's possible it is compatible with direct LiFe connection since it's max voltage is below norminal LiPo voltage.

 

[Tony]

The AR7200BX can handle up to 8.5vDC input.

 

[pvolcko]

Really? Cool. Connect away!

 

[HeliDinoRC]

If you plug a 2s Rx battery directly into the Rx wouldn't the servos loose power/torque/speed as the battery wore down?

 

[pvolcko]

Yes. This is one of the advantages of running a BEC, constant power and voltage throughout the flight. Rx pack advantage is high current delivery (practically unlimited) for HV servo setups as well as a general sense of higher reliability compared to a BEC.

 

[cml001]

Yeah... My option as well... Not many guys at my field run a rx pk.. Most do the BEC... Yet they all talk as tho it's not preferred... I don't get it, but my current project is gonna be rx pk for sure!

 

[HeliDinoRC]

I have a 2s Rx battery with a Rx lead as well as a Dean's connector lead (used for charging). If I go this route and use the 2s Rx battery plugged directly to the Rx, is it advised to have two leads from the Rx battery plugged into the Rx? To do this could I just solder two Rx leads to the female side of a Dean's connector and then plug those to leads into the Rx?

 

[pvolcko]

I don't know on this one. I would guess yes to wanting two connectors. Servo type connectors have a limited current handling capacity. Using two will distribute the power draw between them and prevent a single connector from melting or failing. For a 550 chances are you could get away with a single connector connection since the current draw isn't likely to be too taxing. For a 700-800 size heli I'd recommend two as a minimum.

There are actually alternate wiring schemes for high current, high voltage servo setups that effectively distribute power from the battery or BEC directly to the servos without going through the Rx/FBL. This is another advantage to using one of the higher end Western Robotics BECs that has a built-in power buss where the servos connect to it instead of to the FBL/Rx, it will provide high current to each servo without depending on the FBL/Rx power buss. This will reduce the heat build up in the FBL/Rx due to handling high currents to servos and it will also reduce the chance of it browning out under high servo loads.

 

[cml001]

Not sure how all that works on the big boys, I'll be using the RCE-B6X.. Guess that's the same as a BEC.. But with a 2s