Spark Eliminator

**hdurrer** · 10-21-2016, 06:20 AM

Hey guys, how can I eliminate the spark you get when you hook up your battery packs. I have read a lot of stuff on how to but what no body will share or have not shared is what type or what size resistor to use. I am running 5000mah 25c in series for 6S. Can anyone help

**Rcforever32** · 10-23-2016, 08:18 AM

Hi, sorry no one got back to you, my father is an electrical engineer and he said you can use a device that is called an, inrush current limiter, it's a variable resistor, and if you google those words you should see a picture of them... he thinks he has some at home as well... you can pm me if you want or need anymore info... I am still trying to figure out how to get pictures on here, they make it kind of difficult to do on here lol... you can also provide an email in pm , and I can send you links or pics of this device as well... hope this helps! --Scott---

**hdurrer** · 10-26-2016, 06:46 AM

Thanks for the info. I will research what you gave and hope it works. I also agree with you, I have been wanting to post pictures and I can't figure it out.

**dontrinko** · 10-26-2016, 08:06 AM

The spark is annoying but not dangerous . I'm guessing that a 100 ohm resistor would stop the spark. Put the resistor in series with one side of the battery and attach both sides of the battery.
after connecting it wait about 5 seconds the Remove the resistor and attach the battery. You can not operate the boat with the resistor still in the circuit.
The spark is caused by a capacitor charging when you 1st hook up the battery. When you are done the capacitor gradually discharges thus a spark the next time you use it. Don

**Rcforever32** · 10-26-2016, 04:56 PM

@hdurrer,I have a pic on my phone of tht variable resistor...just have to re- learn how to post pics...im not new to Rc, or this forum... just been out of the loop for 4 years... I used to b Rcforever27... lol I've been reading tons and tons of posts and even searched for my old name on here to re read all my posts lol.... i at in the beginning stages of rebuilding my second spartan.. with the second gen hull... as I sank it like 4 years ago and it kinda got put on the back burner lol... I have pics posted on the sticky page for pics of Spartans jus scroll til u see Rcforever27... I have 3 Spartans currently, and only 1 runs... my goal is to get all 3 going again... thanks for reading , and I look forward to more posts and hearing more questions and stories on this great forum ��--Scott--

**Rcforever32** · 10-26-2016, 05:06 PM

@ don, you are absolutely correct, however, these variable resistors are obviously a resistor when it sees current spikes, then once the spike is gone they become a wire, no current restrictions...now please excuse me if I'm not explaining right, as I'm getting most of this info from my father who knows a little more than I do when it comes to electronics lol

**Rcforever32** · 10-26-2016, 05:08 PM

Also, I just want to clarify, im talking about variable resistors, not fixed resistors..

**Doug825** · 10-26-2016, 06:56 PM

The spark isn't really a big deal but if you want, you can buy a spark eliminator from Kintecracing for $15.

**Rcforever32** · 10-26-2016, 07:00 PM

Agreed @ Doug... would be a little different if the voltage was doubled.. then I would start thinking about doing something...

**dontrinko** · 10-27-2016, 08:11 AM

The variable resistors become a low resistance for the devices they are used on but for RC boats that draw 80 to 120 amps they would limit performance. They would be the equivalent of a very bad connection. All IMO; Don

**Panamon Creel** · 10-27-2016, 02:43 PM

Originally Posted by Rcforever32

@ don, you are absolutely correct, however, these variable resistors are obviously a resistor when it sees current spikes, then once the spike is gone they become a wire, no current restrictions...now please excuse me if I'm not explaining right, as I'm getting most of this info from my father who knows a little more than I do when it comes to electronics lol

The spike eliminating variable resistors are generally NTC Thermistors which start out with a high resistance when cold and while connected under load heat up which lowers their resistance until they are almost fully conductive, like you say become like a "wire". However just like a wire this NTC has to be sized in accordance to the power that flows through it thus would have to be pretty big for this application in order to handle the power the ESC/Motor requires during normal run. Furthermore the NTC will consume some power to function so you will get a power loss.

IMO way too much effort/resources for fixing something that is not a problem to begin with.

**Panamon Creel** · 10-27-2016, 03:17 PM

Originally Posted by Rcforever32

Agreed @ Doug... would be a little different if the voltage was doubled.. then I would start thinking about doing something...

Double or triple it, still won't be a problem with the little spark you get from the very short charge up load for the ESC capacitors. Now if you'd disconnect the plug under a high load then you could get a problem since it essentially could create a large arc that ionizes the air and is very hot ( think SMAW welder) but that's not the case here.

**Rcforever32** · 10-27-2016, 07:32 PM

Agreed 100 percent panamon... thanks for chiming in and explaining it better lol. Like you said not worth the trouble...

**hdurrer** · 10-31-2016, 06:54 AM

You guys lost me a long time ago. Have no idea what you mean or how to apply. I hear that the spark is not good for the ESC and now I'm hearing its ok. I'm confused.

**dontrinko** · 10-31-2016, 08:14 AM

It is normal for that esc. mine does it ,far as i know they all do it. Most have done nothing to prevent it and their esc 's still work fine. Don

**Rcforever32** · 10-31-2016, 09:28 AM

The only time I would be more concerned about this normal condition , is when running higher than 6s ... higher voltage usually means higher current levels and a bigger spark... jmo

**Panamon Creel** · 10-31-2016, 03:31 PM

Originally Posted by hdurrer

You guys lost me a long time ago. Have no idea what you mean or how to apply. I hear that the spark is not good for the ESC and now I'm hearing its ok. I'm confused.

The spark doesn't cause problems for the ESC. It might cause minimal wear on the tips of the plugs where the initial contact is made but that's about it.

Originally Posted by Rcforever32

The only time I would be more concerned about this normal condition , is when running higher than 6s ... higher voltage usually means higher current levels and a bigger spark... jmo

Well higher Voltage mean less current for the same power

You'll need far more than 6S to get a good arc going when connecting ( aka dielectric breakdown, air ~3KV/mm gap) as well as some significant load behind it to maintain it. The load from those tiny caps of the ESC is insignificant.

**Rcforever32** · 10-31-2016, 04:04 PM

Panamon creel, you are absolutely correct. I think the original poster of this thread was concerned more than anything else of wearing the plating off the connectors, as I was at one time, however in my over 15 years being into Rc, never have I ever replaced a connector due to the plating wearing out or causing issues.. knock on wood lol...

**Panamon Creel** · 10-31-2016, 05:45 PM

You'll likely have more wear of the plating on the whole blade contact surface from the friction on each connect/disconnect cycle than you get from the arcing on the tip of the blades on connect with discharged Caps.

**Rcforever32** · 10-31-2016, 07:09 PM

Yea that's def true..

**hdurrer** · 11-02-2016, 05:40 AM

Thanks guys, I think I will not worry about it until I decide to use more power over 6S. Thanks again.

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