DIY Anti-Spark Bullet Connectors.

chaka

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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.

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What voltage range will this work well with?
 
Vanarian said:
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 said:
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.
 
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?
 
Montiey said:
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-M...hash=item43c71ddea7:m:mZvMVAiYF4JdPzgd97og_0g
 
Montiey said:
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.
 
icerider said:
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).
 
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.....
 
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.
 
itchynackers said:
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.
 
Trbt555 said:
itchynackers said:
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"?
 
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.
 
itchynackers said:
If I knew the math, I wouldn't have asked. Anyone have a better answer than "probably"?
Maybe.

Still grumpy over the Vikings? <wink>
 
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