Jim,

The reason Schulze cares about the input voltage is that its used to setup the cutoff. The algorithm they use for that is somewhat useless for lipos (modern ones at least) and more geared for round cells so it should not really matter.

That being said, in some 450+ connections to my ESC over the course of a year...my connectors (Deans) were pretty much destroyed, with the tips nearly totally gone. My ESC never once complained and still works great. I switched connectors and didnt notice any difference in performance so the old ones were probably still ok. I am fairly convinced that other than being a nuisance the spark is not causing any problems.

Here is my removable, anti spark arming plug. I soldered the female connectors to a two sided printed circuit board (soldered on both sides), isolated them electrically, and soldered a 100 ohm resistor across the gap. The 1/4 piece of wood will be glued into the plane and the circuit board will be removable by pulling the sheet metal screws.

Next thing to do is to measure the losses if any at max current due to the additional connectors.

Jim O

Jim, have you been able to do any further testing of the anit spark device to see if there are material losses?

Thanks,
Keith B

Thanks for asking. Sometimes I need a poke to get going.

Let me describe my setup. I'm using 5.5 mm bullet type connectors throughout. I've added a two wire cable/connector on the ESC side of the two bullets on the ESC input. This is connected to the telemetering/data recorder. In the base line configuration the two 5s4p packs are connected in series by one set of bullet connectors and the plus and minus output of the resulting 10s4p is connected to the ESC or to the ESC through a Wattmeter. The voltage at the ESC is measured at wide open throttle.

With the arming circuit in the return line and an extension in the high voltage line I measured the voltage again at the ESC at WOT.

I concluded that the losses were negligible. It is a little difficult to get consistent readings because the voltage is dropping as the battery is discharging and it is probably trying to increase as the battery gets warmer. In any case the readings were within a tenth of a volt. If I had repeated the baseline it would probably dropped another tenth.

The more I think about it the more I like the idea of the arming plug. I heard one story of a motor seizing resulting in the ESC burning. The plane was landed as quickly as possible but the guys had to be heroes to get the battery unplugged before the plane burned to the ground. Having the arming plug that could easily be pulled in an emergency would have been nice to have that day.
Also, it gets rid of the arcing at plug-in.

Jim O

Thanks for the feedback Jim. I think I'll run out tomorrow and buy some circuit board and try to build myself one of those arming plugs.

I've always run the fuel line through the fuse side with an external tube connected to two MK elbows for fueling. It's kind of funny that after going electric I'll still have the similar looking gadget on the outside.

With my glow setup I have a personal rule that I'll never take the connecting fuel tube out of my flight box until I've verified that the wings are secured with the wing bolts and the ailerons are hooked up correctly. Also, the tube goes before any wing bolts are removed. With an arming plug I can follow the same rules!

Jim, are you using 12 gage multi-strand wire for all of your leads?

Keith B

Here's another approach to an arming "key" system. A Deans socket Aeropoxied to the LG plate and wired in series with a batt / ESC lead. The key is a Deans plug to which a handle / jumper is attached. The handle is a piece of SS Hatori pipe mount material soldered to the Deans and shrink wrapped for insulation. The handle is bent to match the LG strut angle so as to be less obvious.

Earl.
That is very similar to the solution I am using.
I have made a small 1/4" plywood plate that is glued to the inside of the fuselage.
There is a set screw in the plywood plate that holds the female Deans socket in place. I only need to loosen the screw a couple of turns, and the plug can be removed.

I actually wanted my connector to be as visible as possible, for safety reasons. I see it as a kind of emergency switch, so I don't want to hide it.

Regards,
Magne

Just great now back to the shop to make mods, LOL good ideas.
Steve Maxwell

>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.

Hi, which exact brand and code number of connectors are these please?

Can you post a close up picture of one?

Thanks,

Alistair G.