DIY Anti-Spark Bullet Connectors.

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chaka
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DIY Anti-Spark Bullet Connectors.

Post by chaka » Jan 09, 2016 12:37 am

The picture says it all! I took a little break today while I had some VESC's in the oven and crafted this little gem. I used three 1K resistors to make it.

After cutting the tip off the female connector I used the male connector as an alignment jig. I remember seeing something like this on Google images a few months back and have been meaning to give it a try every since.

Image

whatever
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Re: DIY Anti-Spark Bullet Connectors.

Post by whatever » Jan 09, 2016 5:16 am

that it is a brilliant idea!

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Re: DIY Anti-Spark Bullet Connectors.

Post by Vanarian » Jan 09, 2016 6:52 am

Very cool looking, how does it work? :?:
I needed to turn Air Gear stuff into reality so I am making this!
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Re: DIY Anti-Spark Bullet Connectors.

Post by itchynackers » Jan 09, 2016 8:29 am

What voltage range will this work well with?
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Re: DIY Anti-Spark Bullet Connectors.

Post by icerider » Jan 09, 2016 9:47 am

That is a cute implementation, certainly better than a resistor with alligator clips.

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Re: DIY Anti-Spark Bullet Connectors.

Post by chaka » Jan 09, 2016 12:25 pm

Vanarian wrote:Very cool looking, how does it work? :?:
As the male end enters the female housing the resistors slow the in-rush of current effectively per-charging your ESC before the male end reaches the second section of the female housing. XT-90S connectors work in identical fashion.
itchynackers wrote:What voltage range will this work well with?
I have tried it at 6s, I'll grab a 12s pack and try it a little later when I am in the shop.

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Re: DIY Anti-Spark Bullet Connectors.

Post by okp » Jan 09, 2016 4:09 pm

awesome work - you just never stop bringing new stuff to the table !

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Re: DIY Anti-Spark Bullet Connectors.

Post by rmrf » Jan 09, 2016 4:10 pm

DIY XT-90S, but nice anyway! Thanks for sharing!

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Re: DIY Anti-Spark Bullet Connectors.

Post by Montiey » Jan 09, 2016 4:22 pm

For the resistors, do they need to be any specific value? If I used 4 of them would they need to be need to be 2500 ohm each assuming I could use a single 10k?

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Re: DIY Anti-Spark Bullet Connectors.

Post by chaka » Jan 09, 2016 4:53 pm

Montiey wrote:For the resistors, do they need to be any specific value? If I used 4 of them would they need to be need to be 2500 ohm each assuming I could use a single 10k?
I just tested this on 12s and three 1k resistors seems to be the sweet spot. You want at least three resistors to have some structural integrity with the final assembly.

You can buy the smd resistors from ebay for pennies. 100 resistors should cost you less than $4 for 100 resistors: http://www.ebay.com/itm/0805-2012-Metri ... zgd97og_0g

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Re: DIY Anti-Spark Bullet Connectors.

Post by icerider » Jan 09, 2016 8:29 pm

Montiey wrote:For the resistors, do they need to be any specific value? If I used 4 of them would they need to be need to be 2500 ohm each assuming I could use a single 10k?
They are in parallel. His 3 1K resistors will wind up being about 333 ohms total.

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Re: DIY Anti-Spark Bullet Connectors.

Post by Montiey » Jan 09, 2016 10:52 pm

icerider wrote: They are in parallel. His 3 1K resistors will wind up being about 333 ohms total.
How does the math work out for that? I understand that more resistors means less resistance (when in parallel).

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Re: DIY Anti-Spark Bullet Connectors.

Post by Gregory » Jan 09, 2016 11:02 pm

If the values are identical like above you just divide the resistance of one resistor by n where n is the number of resistors. 1000/3=333 Ohms.

If not same resistance the formula is still easy. 1/R=1/R1+1/R2.....


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Re: DIY Anti-Spark Bullet Connectors.

Post by Montiey » Jan 09, 2016 11:08 pm

Ah, that makes sense.
:)

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Re: DIY Anti-Spark Bullet Connectors.

Post by itchynackers » Jan 10, 2016 8:31 am

Been looking for something similar to this, except I need it for 25s lipo with a 18 fet lyen 4115. Anyone know how many resistors would suffice? Not sure of the capacitance of the controller.
9c 9x7f w/ 12awg phases
9c 8x8r w/ 10awg phases, temp sensor, vented
9c 6x10r w/ 10awg phases, temp sensor, liquid cooled, 3rd Place Pikes Peak 2012!

"Don't argue with the galactically stupid...they drag you down to their level and beat you with experience"

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Re: DIY Anti-Spark Bullet Connectors.

Post by Trbt555 » Jan 10, 2016 10:06 am

itchynackers wrote:Been looking for something similar to this, except I need it for 25s lipo with a 18 fet lyen 4115. Anyone know how many resistors would suffice? Not sure of the capacitance of the controller.
Do the math: if 3 x 1K in parallel is ok for 12S, then 3x2k will probably be OK for 25S.
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Re: DIY Anti-Spark Bullet Connectors.

Post by itchynackers » Jan 10, 2016 10:41 am

Trbt555 wrote:
itchynackers wrote:Been looking for something similar to this, except I need it for 25s lipo with a 18 fet lyen 4115. Anyone know how many resistors would suffice? Not sure of the capacitance of the controller.
Do the math: if 3 x 1K in parallel is ok for 12S, then 3x2k will probably be OK for 25S.
If I knew the math, I wouldn't have asked. Anyone have a better answer than "probably"?
9c 9x7f w/ 12awg phases
9c 8x8r w/ 10awg phases, temp sensor, vented
9c 6x10r w/ 10awg phases, temp sensor, liquid cooled, 3rd Place Pikes Peak 2012!

"Don't argue with the galactically stupid...they drag you down to their level and beat you with experience"

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Re: DIY Anti-Spark Bullet Connectors.

Post by Trbt555 » Jan 10, 2016 3:21 pm

Ok then.

Current @12S = 50,4V/333 Ohm = 0,15A

Required R for same current @25S = 105V/0,15A = 700 Ohm

So 3 x 2.1K resistors will work, or 4 x 2.8K resistors will work, based on @chaka's findings.

Capacitance will influence the duration of the inrush current.

Play around with this simulation if you want to learn more.
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Re: DIY Anti-Spark Bullet Connectors.

Post by tomjasz » Jan 10, 2016 3:43 pm

itchynackers wrote: If I knew the math, I wouldn't have asked. Anyone have a better answer than "probably"?
Maybe.

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