Connecting a BEC in parallel with an ESC: directly soldered or using a connector?

[TheBum]

I will be setting up my first heli with a separate ESC and BEC and I'm wondering if most people solder the BEC battery wires parallel to the ESC battery wires at some convenient point (e.g. at the battery connector) or use a secondary connector. I might as well make it a poll.

The advantage to using a secondary connector is the ability to disconnect the BEC from the main power and connect it to a pack when working on the bench. It would probably be quicker and easier than disconnecting the BEC from the receiver and plugging a receiver pack in its place.

[Richard F.]

my very first one, to see if my esc would stop getting hot on my blade 400, I soldered it to the deans with the esc. not saying thats the best though. oh yeah, it didnt work. esc still comes down after flight 135degrees. But it was good practice for a bigger heli!

[Larry227]

I've only installed one seperate BEC and that was a Sport BEC on a B400. I also hard soldered it in at the Deans connector.

[kevinator9]

I solder at the connector. It is always pretty simple to disconnect the motor wires or what I always do is set up the esc first for setup and use my radio on throttle hold to program or whenever it isn't flying something.

[Spork01]

Hi Allan. I've done both ways. I found it better when its directly soldered on. Although it was convenient when it was on a secondary connector for the reasons you stated.

[WillJames]

One pack or two on this new heli?

If only one, you may want to use a connecter if you are running a V-BAR on it. If you have two packs, solder it inline on one of the connectors to one pack. This way you can power up the V-BAR without arming the ESC until you plug in your other pack.

[Mr.Andersen]

What im considering when soldering my BEC in paralell with the ESC is there is no possibilities fore any connector to get loose in flight.
If running a separate Rx battery a connector is needed but running it from the flight pack soldering eliminates one fail source.

[michael503]

I've done it both ways., but I like to put connector(s) between the power source and the BEC, just for maintenance convenience.

[TheBum]

Originally Posted by WillJames

One pack or two on this new heli?

If only one, you may want to use a connecter if you are running a V-BAR on it. If you have two packs, solder it inline on one of the connectors to one pack. This way you can power up the V-BAR without arming the ESC until you plug in your other pack.

I'll have two packs and a V-Bar.

Doesn't running the BEC off of only one pack cause the IR of the packs to become more unequal as the flight wears on? I know the current draw through the BEC is less than 1/10th that of the motor and that there are a few people running this way, but I don't know what effect it has on flight time.

[Tisondm]

You may want a seperate conn for Bec for this reason. I know there is a fail safe on my esc but if something were to glitch. Your Esc could arm before your Receiver has control of the throttle.

I soldered my Esc and Bec leads on my 600 butt I have a seperate conn for the Esc lead going to the receiver. I don't connect that one until the Rec has armed.

Just something to ponder.

[nwmtech]

Generally I try to avoid adding un-needed connectors but I really like the ability to disconnect the BEC and power it from a single battery for bench testing. I've got some old worn out batteries that work great for just this purpose. Personally I think a good quality connector that's well supported on either end is perfectly fine and very convenient in this situation.

Originally Posted by TheBum

I will be setting up my first heli with a separate ESC and BEC and I'm wondering if most people solder the BEC battery wires parallel to the ESC battery wires at some convenient point (e.g. at the battery connector) or use a secondary connector. I might as well make it a poll.

The advantage to using a secondary connector is the ability to disconnect the BEC from the main power and connect it to a pack when working on the bench. It would probably be quicker and easier than disconnecting the BEC from the receiver and plugging a receiver pack in its place.

[TheBum]

Actually, I just realized that I could just permanently wire the BEC to the series adapter I'll be using anyway. That way, I could do the normal process of connecting both packs to the adapter first, which would get power to the BEC regardless of whether I put 6S or 12S across it, and then plug the adapter into the ESC to get power there. If I wanted to have only electronics power, I could just omit the ESC connection.

Would the ESC power connection spark? I know the BEC has capacitors at the power inputs which would cause a spark, but I wasn't sure about a BEC-less ESC.

[WillJames]

Originally Posted by TheBum

I'll have two packs and a V-Bar.

Doesn't running the BEC off of only one pack cause the IR of the packs to become more unequal as the flight wears on? I know the current draw through the BEC is less than 1/10th that of the motor and that there are a few people running this way, but I don't know what effect it has on flight time.

Yes it does potentially, but I never found it to be a problem as I charged/balanced the pairs of packs in series and flew them in series as well. This was on big fairly heavy 90 sized machines and the flying amp draw was so high, the machine electronics were a very small part of total amp draw and did not seem to matter. The ability to have my electronics powered up without the power system powered up was a simple and effective way to do things. Especially with V-BAR I want my V-BAR and radio to get initialized and me check it out before enabling the flying power system. I try to keep it simple and as safe as I can. On the Ion-X, I could not tell a difference in flight time as well. I could get 4 to 5 minutes a flight with the NEU 2 stage or the Actro single stage even with a separate flight pack for the electronics, it did not seem to effect flight time at all.

I think it will still spark when you plug in the ESC, I do not remember a spark at all when the connector with the BEC wired in was attached.

[TheBum]

Originally Posted by WillJames

I think it will still spark when you plug in the ESC, I do not remember a spark at all when the connector with the BEC wired in was attached.

I don't have the heli kit yet, which will include the ESC, but I do have the BEC and decided to try a test this afternoon with a couple of my 6S test packs wired in series. My results pretty much agree with your assessment of BEC sparking. There was a spark, but it was a very small one compared to what I get when I connect my Atom 500's ESC (with built-in BEC) to a 6S flight pack.

[kevinator9]

The ESC you will be getting will spark when you connect 12S like nothing you've seen before!!!
The arching is enough to instantly put arching marks on your heatshrink and bullet connectors (if that is what you would use to connect the 12S to the ESC).
Luckily the ESC comes with a resistor on a separate lead which lets the current slowly charge the capacitors and stop the spark when you plug in your larger lead.

[TheBum]

Originally Posted by kevinator9

The ESC you will be getting will spark when you connect 12S like nothing you've seen before!!!
The arching is enough to instantly put arching marks on your heatshrink and bullet connectors (if that is what you would use to connect the 12S to the ESC).
Luckily the ESC comes with a resistor on a separate lead which lets the current slowly charge the capacitors and stop the spark when you plug in your larger lead.

I was already planning to use an anti-spark lead, but it wouldn't have worked on the BEC with my proposed setup on the series adapter; I would have had to add separate leads to the battery wires, which I was trying to avoid. Since it appears the BEC won't be a problem, I can proceed with the anti-spark on the ESC. Here's a diagram of the wiring:



I'm using EC5 connectors for the main power (including on the batteries), i.e. there's no good way to make sure one pole connects first, hence the redundant ground path on the anti-spark. I believe I remember JLH_1 telling me that the resistor was on the positive lead; if not, it really doesn't change the wiring except that the resistor moves from the positive wire to the negative wire (and I'd have a redundant positive path instead).

[VoltAge]

why dont you just connect a v conector to yhe battery, conect one side to the esc and one to the bec? then you could easily take it out after

bec
battery

[TheBum]

Originally Posted by VoltAge

why dont you just connect a v conector to yhe battery, conect one side to the esc and one to the bec? then you could easily take it out after

bec
battery

Every time you add a connector, you lose power through the connector. I want to keep the number of connectors in the motor power path to a minimum and still be able to use the batteries individually on my Atom 500.

[WillJames]

The spark arrestor is a good idea. On the Ion-X even on 10s the deans would wear out in like 100 flights due to the MAJOR arcing that took place when you plugged them in. They turn black very quickly without the arrestor.