Hi guy's
What kind of connectors do you all use between battery and regulator ?
I like the Deans for their compact size and polarity control, but do they stand the high currents without generating significant loss?
While I have your attention:
- Do you use some kind of connector availabe on the outside of the fuselage, for safety purposes? Why / why not ?
- How do you cope with the spark each time you hook up the battery, it does eat the connectors does it not ?

Working on my Oxalys plug-in wing for electric (Cyclon).

Ola Fremming
Norway

Hi Ola

How are you?

I used Deans last year and they work well, but they need to be soldered properly so as not to distort the plastic housing. They did work fine but the arcing upon connection eats the tips of the contact quite quickly.

The main reason I have went away from Deans is they dont offer a nice way to build a 10s pack without a separate Y built either into the pack or into the ESC. With bullet connectors its easy to just have on set hook the positive and neg. leads of the battery together and then you just have a normal connection from the battery to ESC and chargers etc. This is good for series charging 10s packs on the bigger chargers.

I have moved on to bullet connectors (5.5mm) from Steve Neu in the US. There is very little difference between Deans and these at the power levels we run at, but the bullets offer more flexible connection options for the batteries I think.

http://www.neumotors.com/store/index.html

- I do like the idea of having an external connection outside of the airplane. You see many people connect up the batteries and then have the plane site on the flightline for a number of minutes "live" while the canopy etc is replaced. This concerns me that sooner or later that live motor is going to power up unexpectedly. With external connections you can connect the motor right before you are ready to fly and disconnect it immediately afterwards, without the need to go into the plane.

- Spark....it happens, sometimes its a bad one, sometimes there is no spark at all. I have yet to hear of a solution for it other than getting the connectors together quickly and forcefully...that seems to help minimize it. If you try to very carefully connect them it arcs worse.

Regarding sparks: sit back, relax, and enjoy the show! It's one of the advantages of flying electric.

I had an external connection last year, but this year I'm not going to. I'm going to use the receiver power switch as my safety. The ESC can't turn the motor if the ESC isn't receiving power from the RX.

And I'm switching to bullets, too. Cost is the same, but I know that sometimes I will be charging 5s @ 2C and sometimes 10s @ 1C, and with bullets that doesn't require adapters anywhere. Also, Deans have significant material loss due to arcing after about 150 powered connections, so I'm going to have to replace some of them anyways.

-Adam

Hi Ola,

I have made all connections using 4mm gold connectors, which I think is the most common way to do it in Europe. Also I have made an external "arming" system so I can wait until the last minute to connect the battery to the ESC. It has also been made with 4mm gold connectors as shown in the images below. The great thing about these connectors is the fact that only the tip of the male plug and the edge of the female sockets will see the spark during connection, so the contact surfaces will remain intact even after many flights. I would guess I have connected the arming +100 times, and you can see the condition of the connectors in the photos below. Not a problem in my mind.

Adam

I'm not so sure that trusting the componentry is a good idea. Using the (lack of ) rec power to safety the ESC works OK if nothing fails. I recently observed an electric model (medium sized) come to life in the rear or a fellow modelers truck (open and backed up to pit tables). The rec was definitely off, yet something failed. Fortunately, it just ate the owners field box before it could be restrained and the batts disconnected (as they should have been anyway).

An external method of disconnecting the batts seems a prudent practice, given the consequences of an unplanned motor run.

What do you folks do about protecting against reverse polarity? It seems as though one will eventually reverse the polarity if it can be done. Any comments?

Jim O

Hi Jim,

Well I always connect the female sockets to the plus (red) cable and the male plugs to the minus (black) cable on the ESC and vise-versa on the battery (normal practice when running the 4mm gold connectors). That makes sure you will never fry the ESC anyway. You can however still short circuit the battery itself.............

On the TP 5300mAh packs I'm running I have taped the two 5S4P packs together and made the plus cable short on one and the minus cable short on the other. The two short cables will connect to each other and the two full length cables will connect to the ESC.

As Morten said, male on one lead, female on the other makes reverse polarity difficult. Shorting the pack is possible though, so when the battery is not in use I cover the male bullet connector with a large peice of fuel tubing (that fits tightly so it wont come off on its own). So far so good

Thanks for the feedback guys. I was hoping you'd describe what you did.
As far as the arcing goes, how about putting a 100 ohm resistor across the sockets for the arming plug. That way the capacitors in the ESC will be charged slowly when the packs are connected. The unlimited current into the caps cannot be a good thing. If you try to run the motor without the arming plug you will blow the resistor, but hopefully you will only do that once.

Jim O

You're right, Jim.
There are actually capacitors specially made to withstand the sudden arc-ing connection to a battery. The automotive people use them, but I don't know about any rated for a 40-Volt arc. What we need is a two-stage connector. As you plug in, you wipe against the resistor-limited path, then through into the hard connection. That will limit the time and opportunity for bumping the throttle while in the current-limited path. So do you figure 100-Ohms is enough current limitinng? I'll try it myself, and let you know.
Dean Pappas

the new power jazz 63V (15S...!) from Kontronik has a lot of clever features built in (unfortunately, no dynamic breaking, the boys must have run out of talent at that point).

here what they say:

"Even its appearance shows that it‘s a strong one. Based on the JAZZ software we developed an ESC like none before among Kontroniks product range:

13-63V, i.e. 18-45 cells NiCd/NiMH or 5-15S LiPo
The spilled housing of the Power Jazz 63V gives perfect protection against mechanical damage. Additionally it makes the Power Jazz 63V 100% waterproof.
The Power Jazz is 100% protectet against reversal polarity. The exchange of plus and minus of the battery, no matter how long, does not damage the ESC.
Continues power is no problem for a Power JAZZ 60V, cause it‘s protected against over heating. The internal fan cooling guarantees that also in closed bodies a Power Jazz 63V will not get too hot. For boats KONTRONIK offers a water cooling instead of the fan.
New electronic circuits „anti-spark“ avoid bothering sparks when connecting the battery. Advantage: no scare and no burned connectors.
6 mm2 motor cables guarantee less losses on the cables and mechanical robustness.
Compared with ESCs like it from other companies the Power Jazz 63V surprises with an excellent prize.The Power Jazz 63V is nearly undestroyable. A strong partner for all modelers having strong ideas. " end quote

so, adam, if you like the sparking, fine. maybe you are younger than i am i prefer not to scare myself to death everytime i plug in the thing! the 6mm connectors (also sold by steve neu in the u.s.) are very good, as long as you don't touch them. even dry fingers leave a grease stain and that reduces current flow on a polished contact by a country mile!

roger

Roger, I probably am younger than you ;>

Are you coming to the US Nationals this year? It's going to be one hell of a contest. FAI is flying F07, many people are going to be there, and the weather is always great.

-Adam

Dean,
Can you let us all know and how to wire it up? I can solder, but that's about where my electrical abilities stop. Sure would like a way to eliminate that spark!

Verne Koester

We need to either lower the voltage or lower the current. I read somewhere that you could get an arc with as little as 40 Volts and one Amp. So I'm thinking about a half amp might do it. Let us know.
Jim O

hi adam, hi jim o.

no, i don't fly on the international circuit any more, that's been a while. i started pattern flying in 75 after the WC was held in berne, switzerland. before that, i was just sunday flying. but having read all the stories by our famous fellow forum member OhD (jim, you were my RCM-hero!) before that and then actually seeing dave brown screaming through the swiss alps with that checkerboard plane on at least 50% nitro in that OS60FSR had me sold. i never made it to the swiss team for WC's in F3A, but flew F3D pylon at 3 WC's in 89,93 & 03. nowadays, engines are a lot quieter, props are massively bigger, and alas, i have to start breaking on those downward legs in order not to let the plane run ahead of my aging brain..but it still is the same great fun game!

nice talking to all you guys on this platform!

roger

Hi Roger,

I'm glad someone was reading all that good stuff I was writing in RCM. I remember the late 70's very well. The high point of my flying career was when I beat two world champs, your Bruno G and our Phil K, in a contest here in California. To be fair to Bruno, he was flying one of Phil's airplanes.
I too was more impressed with Dave Brown than all the "top guys" before him. Most of our National Champs didn't know how to use the rudder in those days.
I'm hoping that this electric stuff will get me all charged up to attend a few competitions this year. We'll see how it goes. Right now I'm trying to get my new knees working and it looks good so far. I'm already walking a mile and it has only been 4 weeks.

Best Regards, Jim O

Hi Morten,

I decided to pull the Dean's connectors and use individual 5.5 mm connectors as you have done. I'm also considering the arming jumper. I'd like to make the two females in the fuselage a removable assembly and have one of them soldered directly to the ESC. The assembly has to withstand a fairly high insertion force so the load needs to be spread out on the side of the fuse. I was wondering if you had any tricks in your mounting method.

Jim O

Hi Jim,

I made a support plate for the two sockets and glued it to the inside of the fuselage. If the fuse is carbon fiber like my Synergy make sure the sockets are insulated using heat shrink tubing, since carbon fiber is a good conductor!

As you can see the support plate is made up by a piece of fiberglass plate (fiberglass insulates) and a piece of balsa wood. The gold 4mm sockets were glued directly to the fiberglass plate and afterwords the sockets were covered with the heat shrink tubing. Then the balsa block was glued to this assembly and lastly the complete assembly was glued to the inside of the fuselage. It has worked well, and the fuse does not flex the slightest when it is being "armed".

I actually only fit one socket into the fuz side, the negative female from the ESC. I have another hole alongside which is finished off with an old MK fuel dot bezel. The negative battery lead is passed through this bezel when installing the battery and left dangling. When you want to arm you push it into the socket.

Advantage - no extra plug and socket electrical resistance. Disadvantage - you cant fit an anti sparking resistor across the two sockets.

Malcolm

Here's what was reported in another thread from Schultz about the arcing.

" OK chaps, just got back from the Dortmund show, where I had a nice chat to Ulf Herder and Matthias Schulze about this problem. They say that the spark cannot possibly do any harm to THEIR speed controls and the advice was to just live with it and replace the eroded gold connectors when they eventually needed it. They also said NOT to use any resistor in circuit when first connecting one of their ESC's as they do a voltage measurement when the pack is first connected and the resistor will not allow an accurate measurement. Obviously, they can't comment about ESC's from other manufacturers, but we now know the inside information about Schulze's. "

This is kind of interesting. I can't believe that the RC time constant is such that the input capacitor wouldn't be fully charged in less than a second. I'm wondering if the "idle" current is high enough to cause a significant drop in voltage with an external 100 Ohms. If it is, it would suggest one wouldn't want to connect his batteries until just before he intends to fly.
I'll try to run some tests on the Hacker this weekend and let everyone know.
Jim O

Once again, I'm with you on this, Jim.
It's a simple test with a voltmeter,
and as soon as I get my one pack back (a single cell was damaged by a battery cycler)
I will will run the test on my CC HV85 and 10S combo.

I trust that your torturers ( I mean therapists) are working you hard?

Dean Pappas

Maybe you'll find the thread useful. It's over my head, but seems to pertain to what your trying to do.

http://www.rcgroups.com/forums/showt...ht=+fat+spark+

I breadboarded the no-spark set-up on the Hacker and it looks good to me. I measured the voltage on the input to the ESC, after the 100 ohms and the wattmeter. First I tested without the resistor, got the spark, and measured 41.7 volts. I'm not sure I had the wattmeter in the circuit on this test. With the 100 ohm resistor and wattmeter, no spark, and 39.5 volts. In both cases the voltage was at its peak almost instantly. I can't see that the ESC should care if the voltage is 2.2 volts lower.
It looks like the idle current is 10 to 20 milliamps so it is not a big deal if you connect everything and sit around for 20 minutes before flying.
I'm going to build the real thing next.

Jim O

No spark feture is a must om setups over 10s lipo, im using 2mm gols, 3mm, 4mm silver kontgronik and 6mm gold on 15s setup, Jeti prototype have none spark feture, Schulze have big probblem in big outrunners so i dont use them now, same goes with CC, dont want to risk anymore ESC, motors.