So who here knows a lot about electronics?

[Greywolf74]

Ok, so I was reading on the internet and I ran across a post from a guy say to elimiate teh arch you get when you plug a lipo into an ESC (or charger etc,) you can cut the negative lind and put a bullet connector in its place with a 1-500ohm resistor also connected to both sides of the bullet connector. I did this very thing on my MMM on the negative side using a 500ohm 1/2W resistor but it still archs. Did I do something wrong or is this guy an idiot?

My next question is, If it doesn't work will it hurt to just leave it there or do I need to go in and remove the resistor?

Heres the diagram from the website I saw. He gives no other info other than this diagram.

 

[trax de max]

you can buy the same leads from stores now. There was a few people used it in the past but don't hear much about it now. did you not have to change the size of the resisitor

 

[hamz9561]

It doesn't make any sense to me why it would work. All that the resistor is doing in that circuit is lowering the total resistance. That doesn't really eliminate the spark. In a standard lead there isn't a lot of resistance to begin with.

As for removing the resistor, it's not really doing much but creating heat and maybe causing a fire. I'd pull it.

 

[slowngreen]

x2 with Hamz. Id pull the resistor too. Just another "mod" that doesn't actually work imo.

 

[Greywolf74]

Thats kinda what I though but I figured Id get some other opinions.

 

[ksrichard]

Unless i misread something. Adding a resistor would riase resistance. To many variables. I dont see how it would work. Extra work for nothing.

---------- Post added at 8:21 AM ---------- Previous post was at 8:18 AM ----------

Unless i misread something . To many variables. Lead size, battery size. The right resister.? I dont see how it would work. Extra work for nothing. Id ditch it.

 

[Rolex]

Electrical contacts arc. That's the nature of it.
If you had a switch in the line, the arc would be inside the switch where you won't see it, but the contacts would still arc when they close.

 

[Greywolf74]

Well. That sucks... maybe I should have tried it with a sidewinder instead of one of my MMMs lol

 

[trax de max]

yep you can't use this with the mamba line

 

[bsodmike]

Seems I'm missing something here. I've not seen any arcing issues so far with my 4S Orion Vortex R8 setup; done about 3-4 runs, recharges already and I've got Deans connectors battery side, 4mm banana's on the ESC.

I'd have thought arcing would have been an issue on the AC side (ESC <-> motor) if any of the leads weren't heatshrunk? Do explain please as I'm hoping to switch over to the MMM next week... thanks!

 

[Greywolf74]

I've seen 2S packs arch but not very often...the higher voltage you go though the worse it gets. Plug a 6S pack into an ESC that can handle it and it will arch damn near every time. Its not a big deal I just thought if there was a handy way to stop it that would be cool.

 

[bsodmike]

Where does it arc exactly?, i.e. is it between the +/-ve Deans terminals as you're mating them together or...?

 

[Greywolf74]

yes. when you're plugging the connectors together.

 

[Rolex]

That's the ONLY place it can arc, at the point that completes the circuit. No matter which plug you connect last, you'll get a spark when it gets close.
Not a problem, it's the way it works whether it's DC or AC.

 

[jgorm]

Did they say to unhook the bullet plug when you plug in the battery? If not then its 100% pointless. I think its a total waste, the arc wont hurt anything. You would need a capacitor not a resistor to reduce or eliminate the arc.

 

[bsodmike]

See this: http://www.rcgroups.com/forums/showthread.php?t=1378186

An inline resistor is used to 'trickle' charge the BEC circuitry in an ESC before the main-leads are connected (a.k.a spark arrestor), however, I've also seen another page stating *not* to do this on a MMM!
@trax de max what's the particular reason for not limiting the in-rush current on a MMM? I wonder if this is related to its 'cell' detection circuitry?

Also see:
http://www.rcuniverse.com/forum/fb.asp?m=11073074

 

[hamz9561]

Unfortunately, that is not true. There will be a small spark even when connecting the smaller battery leads. It just may not be as noticeable.

 

[bsodmike]

Unfortunately, that is not true. There will be a small spark even when connecting the smaller battery leads. It just may not be as noticeable.

Shouldn't it be less depending on the chosen resistor? a larger resistor would limit the in-rush current?

 

[Greywolf74]

Since I've already started experimenting with it I'm eventually gonna try it out and Ill use a larger resistor and see if there is any noticeable spark. I've already got a couple other projects on my bench right now but when I get time I'll let you guys know what I find out.

 

[bsodmike]

I'm stating the obvious but just to be sure, leave the bullet leads open till the caps charge up. A 1kohm wont hurt and connect it for 10-20 secs. Then close up the bullet leads. Hopefully, no spark