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Jun 15, 2019, 06:30 PM
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Lexta's Avatar
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Can I power my bec with a seperate battery on my cc edge 120 HV esc?


I have other large scale planes flying with the bec powered by a seperate 2 cell 2100mah battery and they work well. While checking the wiring diagram for the Castle Creations Edge 120HV esc it states the negative or ground wire o the bec must be attached to the negative wire on the esc.
As my bec is only rated to 11cells and I am running 12cell flight packs I wanted to connect the bec to a seperate battery pack like I have done in other models. It works fine on the ground but I don't want to risk my plane if it is going to cause a problem.
Does anyone know for sure if I need to run the bec off of the flight packs or can I power it and then plug in the flight packs to run the motor?
Any info is good info thanks.
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Jun 16, 2019, 01:25 PM
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FlyingJFPV's Avatar
I'm not sure why you are trying to plug the BEC into your flight batteries, that does not make sense. But, if you are simply trying to pick how to power the BEC, there is no difference in powering from the esc or flight packs, it's all the same circuit. If you are asking to run a seperate 2s battery to the bec and then to your "Reciever", that would be redundant and I'd say just use the 2s batteries as normal.
Jun 16, 2019, 08:18 PM
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Lexta's Avatar
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Sorry I have confused the iasue. I currently run my bec from a seperate 2 cell. This powers the reciever. I then plug 12cell flight pack into the esc which powers the motor.
The edge hv esc states the bec has to be connected to the black wire coming from the esc. Will the esc be damaged or fail if I do not connect the bec to it at Ll. Ie my bec is valued to 11 cells and I was hoping to ontinue to power it independently of the flight packs.
Jun 16, 2019, 08:44 PM
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FlyingJFPV's Avatar
I donít see why it would cause an issue. I run my castle 120hv and an independent pack for rx, same idea as what you are doing with a BEC
Jun 16, 2019, 09:29 PM
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Lexta's Avatar
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Thanks
Jun 17, 2019, 12:21 AM
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vollrathd's Avatar
Quote:
Originally Posted by Lexta
Sorry I have confused the iasue. I currently run my bec from a seperate 2 cell. This powers the reciever. I then plug 12cell flight pack into the esc which powers the motor.
The edge hv esc states the bec has to be connected to the black wire coming from the esc. Will the esc be damaged or fail if I do not connect the bec to it at Ll. Ie my bec is valued to 11 cells and I was hoping to ontinue to power it independently of the flight packs.
Here is the issue.

If you are running a pair of LiPo batteries in series as 6S and 5S to get 11S, you absolutely must connect the external BEC negative black wire to the "Bottom" LiPo pack black wire. And, connect the external BEC red positive wire to the red wire of the bottom LiPo battery pack.

What CC is warning against is connecting the BEC black wire to the negative black wire of the "Top" LiPo pack, which will be six cells from the bottom pack black wire. That raises the black wire of the BEC of the ESC receiver battery connections to some 22 Volts above the bottom pack. And, the black wire of the throttle cable input to the ESC is at zero volts. Short circuits can result.

Powering the receiver with a separate receiver battery pack completely eliminates this potential problem. (Disconnect the red wire of the BEC servo connector to prevent parallel connecting the SBEC and the external receiver battery)

For other readers of this thread, check out the Castle Creations 120 Amp HV Talon ESC. This unit has a built in SBEC that operates off of the full voltage of the 12S LiPo battery pack. (I've got one). The BEC has two servo connectors for the receiver. One is the standard three wire that plugs into the receiver throttle channel. The other servo connector is a power connector that plugs into an unused channel of the receiver.

http://www.castlecreations.com/en/ta...sc-010-0131-00
Last edited by vollrathd; Jun 17, 2019 at 12:27 AM.
Jun 17, 2019, 09:46 AM
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Lexta's Avatar
Thread OP
Thanks Vollrathd.
So to be clear wiring as directed in the edge manual of 2 x 6 cell packs in series ff the bottom pack. The out put to the esc will be 44 volts but the out put to the bec will remain at 22v. ?
So running my 11 cell rated bec will be safe.
If I wire as the diagram shows to the red and black wires of the esc I will be putting 44 v through the bec
Which is too much for my bec but ok for a 12cell rated bec?
If I wire to the top pack only it will likley cause damage?
If I power my bec by a seperate 2 cell battery and do not connect any wires from the bec to the esc it should work fine?
This is how I have been running the bec but the manuals statemment that the black wire of the bec "must" be connected to the black wire of the esc had me concerned.
Jun 17, 2019, 10:46 AM
Registered User
Why not just tap off the balance connector of either battery?

Get a male balance plug for up to 6S, and tap the 1st pin (GND) and the 3rd pin (3S)
Jun 17, 2019, 11:44 AM
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Lynxman's Avatar
A BEC is supposed to eliminate the receiver battery, it's why it's called BEC (Battery eliminator circuit). You can run the BEC from one of the 6S packs instead of the whole 12S shebang, use the pack that makes up the - pole of the total pack. The extra draw from that pack is small enough to probably not matter. Probably under 5 W average.
Jun 17, 2019, 02:05 PM
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Lexta's Avatar
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Quote:
Originally Posted by Lynxman
A BEC is supposed to eliminate the receiver battery, it's why it's called BEC (Battery eliminator circuit). You can run the BEC from one of the 6S packs instead of the whole 12S shebang, use the pack that makes up the - pole of the total pack. The extra draw from that pack is small enough to probably not matter. Probably under 5 W average.
True.
But some warbirds need extra nose weight. I could add a separate battery or I can add lead.
Jun 17, 2019, 06:43 PM
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vollrathd's Avatar

Castle Creations Instruction PDF


Quote:
Originally Posted by Lexta
Thanks Vollrathd.
So to be clear wiring as directed in the edge manual of 2 x 6 cell packs in series ff the bottom pack. The out put to the esc will be 44 volts but the out put to the bec will remain at 22v. ?
So running my 11 cell rated bec will be safe.
If I wire as the diagram shows to the red and black wires of the esc I will be putting 44 v through the bec
Which is too much for my bec but ok for a 12cell rated bec?
If I wire to the top pack only it will likley cause damage?
If I power my bec by a seperate 2 cell battery and do not connect any wires from the bec to the esc it should work fine?
This is how I have been running the bec but the manuals statemment that the black wire of the bec "must" be connected to the black wire of the esc had me concerned.
Here is a copy of the Castle Creations PDF file on using the "Lower Battery Pack " of the two battery pack setup to power an external BEC. This is how I set up all of my battery packs of 10S and 12S A123 cells. Another option is to use the CC high voltage BEC that can be wired directly across the 12S battery pack for receiver power.
Jun 17, 2019, 10:53 PM
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Lexta's Avatar
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Thanks Vollrathd,
It is that wiring guide which screwed me up because it has the word "must" in it.
Which implied to me that running the bec independently of the esc , ie wiring the bec to a stand alone 2 cell battery could cause the esc to fail.
Using "must" implies to me that their is no other way to wire the bec to power the receiver.
Which is why I asked the question.

I have rewired this esc as per the manual but I will run my other large planes from a separate battery as I have done for years.
I wish the manual would say if you wire the bec as shown from the bottom pack the output to the bec will be the voltage of the bottom pack only not the combined voltage of both packs and it is or it is not recommended to power the bec in any other way.
I like to run the receiver by a separate pack in case of damage to the flight packs which have more connection which can fail and run at a very high voltage.
It is my opinion that the receiver will get the 5v or 6v constant power through the bec rather then if I power the receiver straight from the battery where their is a possibility of inconstant voltage going to the receiver. This could happen by a cell dropping out.
Doing it this way just helps me feel safe and gives me a warm and fuzzy about the system.

Thank you everyone for your input. I appreciate it.
Jun 17, 2019, 11:41 PM
Registered User
vollrathd's Avatar
Quote:
Originally Posted by Lexta
Thanks Vollrathd,
It is that wiring guide which screwed me up because it has the word "must" in it.
Which implied to me that running the bec independently of the esc , ie wiring the bec to a stand alone 2 cell battery could cause the esc to fail.
Using "must" implies to me that their is no other way to wire the bec to power the receiver.
Which is why I asked the question.

Thank you everyone for your input. I appreciate it.
Here is how I wire up my giant scale $$$$ models with the primary receiver power derived from a BEC, with a two cell 2500 mah A123 as a back up receiver supply. And, all of my models have my "Arduino VoltSagger" project installed that will warn if their is a receiver voltage issue during a flight.

Arduino Nano Voltsagger
https://www.rcgroups.com/forums/show...t#post40495307
Jun 19, 2019, 03:15 PM
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Lexta's Avatar
Thread OP
I have the definitve answer from Castle Creations. I thank CC for getting back to me with the info.
here is the answer sent to me by Castle Creations.
The warning for the BEC wiring to the negative wire on the ESC is only applicable if powering the BEC from the main flight battery.



If you are planning to run a separate battery to only power the receiver then you do not want to connect it to the ESC in any way. They will essentially be two isolated circuits with no common connections; expect for when they both plug into the receiver.

It is perfectly acceptable to use a separate battery to power the BEC directly. This provides some increased safety margin in the event of a catastrophic failure of the main flight battery. It will still allow you to maintain radio and servo control. The only downside is the increased weight from the extra battery; and you have another battery to charge.

Please let me know if you have any additional questions or concerns. Thanks!
Jun 28, 2019, 03:31 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
Also, all masses should be connected in one point, the starpoint. Otherwise mass is not mass.
Call me lazy
Ground_loop_(electricity) (wikipedia)

Prettig weekend Ron


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