Why use Bullet Connectors in RC Racing?? | XT90 vs Bullet Connectors for RC Drag Racing!
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- เผยแพร่เมื่อ 28 ส.ค. 2021
- What's better, XT90 connectors or bullet connectors? I get a lot of comments about running XT90 connectors in my No Prep Drag Car, a lot of people tell me I should be running bullets straight to the battery. I've seen a lot of this in racing but haven't seen it explained a whole lot. So I figured I'd test it out.
The main advantage I can see is resistance. Without the xt90 connector, there should be less resistance for the current to flow from the battery to the ESC. I'm going to test that today with a multimeter and we'll read the ohms on each wire and compare the two.
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I just traded for a Slash that has bullet connectors. I'd never seen them before and had no idea what I was looking at, but I could tell the guy wasn't trying to scam me, so I just went with it. Now I see how cool they are and I'm really happy. Thanks for explaining stuff.
Glad I could help explain some things. Good luck!
Excellent episode. You did a great job explaining resistance through connectors.
Thank you!!
Awesome! Glad to see someone use the tools to prove it and not just run a car switch run again and guess if it’s right or not. A+ work my man!
Really appreciate that!!
This was a great learning video. You should make more of them as you do them so well.
Thank you! I'd like to cover some more topics but I know I'm not the most knowledgeable on everything. Just trying to share the knowledge I have.
Every contact is a point of resistance , so using the xt90s each wire path between battery and esc has 4 points of contact . Using only the bullets you only have 2 points of contact, one at the bullet and one at the esc. Depending on the size of the bullet it could have more or less resistance than the connectors inside a xt90. PS I use xt90’s on everything
I love the xt90s, run them on everything I have. I'm interested to see how the less resistance helps in racing
Good information!
Thank you!
Wow 50% less resistance. Thank you for answering a question I had too.
👍🏻🙌🏻
No surprises here. And a bullet setup just looks better :)
Getting information is never a "letdown". I try to take in as much info as possible.
I would be very interested in seeing if there was a difference between an XT90 That has 4.5 mm bullet connectors inside Vs a EC5/IC5 connector that has 5 mm bullets inside. I know I've read quite often that larger bullets offer less resistance but kind of curious that how much. Seeing this video leads me to think very minimal between XT90 and EC5. Maybe more noticeable going from an XT90 to 6mm or larger.
Great content keep it up
Thank you! I think I may have an EC5 connector laying around from my Arrma Notorious, I can look into that!
I’m going with bullet connectors soon. It doesn’t only look cleaner, it frees up space and it’s grams lighter
Weight is something else I didn't even realize at first! When it comes to the big xt90 connectors, those are a nice bit of weight you can take out of the car!
Not sure if it's been mentioned. But the only way to properly do this test is if you were to have those bullet connectors hooked up to a battery. And test on the other side of the bullet connectors. That connection is going to cause resistance. Maybe the exact same resistance that the xt90 has. The absolute best would be solder the wires directly from the ESC to the battery
I think someone else mentioned this as well. My idea though, is that the resistance from plugging the bullet connectors into the battery, is the same resistance I'd get there with the XT90 connectors connecting to the battery. The point of the test was to see the resistance between just the wire running to the battery terminals, and how much more resistance was added by adding a connector in that wire
@@FullThrottleRC Exactly. Anytime solder or a joint is involved there will be a resistance. You should get an infrared reading device. Run The vehicle at a high load. Then infrared the wires and the connectors. It will tell you where you're having lost through heat signature.
but how much impedance, curious with wires in close proximity if there is any increase in impedance with interlocking magnetic fields under load and increased flow.
Honestly I think that's a little to "in detail" for what we're doing here. I admittedly do not know much about that, but I'd have to imagine it isn't affecting much with the length of the wire and the size of everything on top of the current we're drawing.
good to know. I use bullet connectors in my "racers" mainly because it's easier to put/take batteries between races and also looks tidier under the "hood"
I'll say that the XT90s were a bit easier for me for charging simplicity since they were the same as all of my other batteries, but it has been simple in the car.
i wonder how an ic5 would have compared. ic5 connectors are .5mm wider and 4mm longer (per side, positive and negative) than xt90 connectors. i would imagine they would have a bit less resistance than xt90s.
That's interesting. I've never used IC5 connectors other than installing them for a customer. I wonder just how much of a difference that little bit would make.
Am thinking to use high-current bullet connectors to make Ebike batteries more serviceable.
Awesome, does the length of wire make a difference in resistance? I'm thinking, if you face the battery the other direction.
Absolutely! The longer the wire, the more resistance it'll have. I can't face my battery the opposite direction right now because of my battery strap. I may be able to redesign it to allow the posts clearance though.
so I’ve seen a lot of people have the issue with the 22s drag car when they do burnouts and passes the tires run the body and destroy the paint. Is there a 1.9 drag tire or a way to stop the rubbing that you recommend?
I run tape on the inside of my body. A little duct tape or masking tape, gorilla tape, whatever you have, put it on the inside where the tire would rub to protect the body.
@@FullThrottleRC I think it would have to be something thick tho unless u run a smaller tire tho
The reason I won't use xt90 on a race vehicle (1/8 buggy/truggy) is the mass of the xt90 plug itself. It can disconnect on a jump/crash during a race. bullet connectors won't.
I can't say I've ever had one come unplugged without the battery flying completely out of the car but that is a good point!
What about flash pack would that take care of the lost
Assuming you mean a cap pack? A cap pack makes up for the votage drop by storing energy in the capacitors, so essentially it could make up for the drop. You still want as little resistance as possible limiting that energy getting to the ESC
@@FullThrottleRC will I run bullets anyway
You didn't take into account that even with bullet connectors, you still have a plug where the bullet connects to the battery terminal. There will be additional resistance at that connection.
I've talked about this in a few comments before but I didn't take that into account as that would be roughly the same as the resistance between the connection between the leads and actual positive and negative terminals of the battery. There is probably a small amount of added resistance in the bullets but I believe it would be a tiny difference between it and the resistance of the connection from the battery terminals to the positive and negative leads on a typical battery
What chassis are you using?
Associated sc5m
Dont Change Your Connectors ~ Hears Why ~ The Batteries With Bullets Connectors Have More Resistance Because The Female Bullets In The Batteries Have A 14awg Wire or Smaller That Connect The Bullets To The Battery Cells Witch Cause More Resistance Then A 10awg Wire Coming Straight From The Battery Cells. Open Up A Old Bullet Connector Battery & You Will See What Im Talking About...I Hope This Helps
That would be IR..
If I am seeing your test correctly there is another variable that you didn't hold consistent. Solder is a terrible conductor. The free wire ends on your xt90 set up appeared to be soldered. The bullet connector set had raw ends
You are correct, that's something I didn't think of as the xt90 came from an old esc while the bullets are on brand new wire. I'm curious how much resistance solder would add to a circuit, could be something else to test
Solder has resistance
Would an EC5 be worse?
I believe the EC5 has 5mm bullets in it just like the XT90 so they should be very similar
Isn’t there bullet connectors in those yellow housing?
Technically yes, which is why I believe there is a little more resistance when using xt90s. The current has to pass through a second set of "connectors" when coming through the battery leads and the connector. With the bullet connector straight to the battery, those connectors are the "battery leads" in that instance.
why xt90 instead of ec5 or ic5?
That's just what I always ran on my RCs. I'm pretty sure they're really similar, I just went for XT90s first and stuck with them.
@@FullThrottleRC ic5's resistence and amp limits are WAY better, so it may be an option for you instead of bullets. :)
What about a qs8 connector
Don't think I've seen a qs8 connector before, don't have experience with them.
Why are you running such long leads? Turn your battery around, and put the terminal's closest to the ESC and Motor. You are already 3D printing your own brace, so make it with relief areas for the bullets. Save yourself the extra wire length. This will also allow you to make one lead longer than the other to help prevent connecting the battery in reverse, and cooking your ESC.
Not sure if you can see it in the video, but if you check out my battery strap, it covers the poles of the battery if I turn it around. I wanted to do that to shorten the leads but I couldn't plug in the bullets that way.
@@FullThrottleRC yeah, I can see that. Like I said, because you're designing, iterating, and 3D printing it yourself, just design in the cut outs to accommodate the terminal's and bullets for turning the battery around. (Semi off topic, I highly recommend the 1up Racing "heat sink" style bullets for ease of removal)
I think you need the female on the bullet as well and the comparison should show more accurate results.
The female of the bullet is a part of the battery so it's a constant as it's a part of the circuit with both connectors. What I didn't take into account is I actually should've had a set of male bullets on one end of the xt90 since it has to plug into those bullets in the battery
I don't know how much of a difference it would make but your test is missing the resistance from the female bullet receptacle in the battery.
Check out some of the other comments to see the full explanation but I didn't include that since both the bullet connectors I'm using and the XT90s, both have to plug into the female sockets on the battery.
Ok so youre measuring a full "bullit connector inside the xt90 against half a bullit on the wire.. why didnt you actualy fit the other half of the bullit on the wire?!?!?!
I'm not sure if I understand what you're getting at. The xt90 connector is what it would be from the battery, through the connector, to the ESC. The bullet connectors are the same, straight from the battery to the ESC. The bullets don't go to anything but the battery, not another side of a connector.
I bit late to this thread but:
As you said V = I x R
Difference in ohms reading about 0.02 Ohms
At Max current draw of xt90, 90A (if available)
0.02 x 90 = 1.8 V of voltage drop
But over the two leads, that's approx 3.6v due to the resistance...
Yep! I've been running the bullets ever since and have made some improvements!
Also, you can't measure what you lose after the female connector on the battery
I'm not quite sure what you mean by this since I'm not measuring anything on the battery itself. I'm testing the resistance in the leads from the positive and negative on the battery, to the ESC
@@FullThrottleRC the battery houses the female of the interconnection. You should simulate this by using a female connector over top of your make and then probe for resistance
@@dbzacs both connectors would have that same female connection in the battery so that is a constant. I wanted to check the variation of the different connectors
Anytime you got less connections you got less resistance that's all it is to it
I have to agree!!
I dont race and i know my dummy ass would fry my esc weekly with bullet lol so im staying wit my xt90 was actually thinking about going ic5
Hahaha there's a reason I went with bright red heat shrink on the positive lead!
That is not the appropriate way to measure the resistance, especially when the resistance is very low
this isn't really a fair comparison. You can't check the resistance with the whole connection of a bullet. I would say check just one side of the XT90 and its probably about the same as a bullet.
I agree but that's the point, the resistance in the xt90 is almost doubled from the resistance using a bullet connector cause the current has to flow through both sides of the xt90 connector. I'm checking the total resistance across the wire from the battery to the ESC with each connector
you're metering a short. you aren't metering ohms unless you are actually metering a resistor, that actually will give you a reading. what you're reading on the meter is a short because you have the two leads touching, just with the wire in between.
Ohms is just the unit of electrical resistance. So the ohms reading when you place a lead on each side of a length of wire is the electrical resistance of that piece of wire. A resistor will read much more electrical resistance, or ohms, cause that’s its job. It’s an electrical component that resists electrical current. But a length of wire can still read ohms on a meter as wire has some electrical resistance as well.
Also xt90 is too heavy.. for racing we want the car to be as light as possible.. 😁 every grams matters.. xt90 is good for bashing like MTs doing high jumps, backflip, front flip..😂
Actually true and something I never really thought about!! We're talking about really small amounts of weight but it is added weight nonetheless
@@FullThrottleRC we go as far as titanium/CF/alum parts and screws for racing .. 🤣
This is a fairly useless comparison. The voltage drop should be measured while load is applied to the circuit.
Note taken, but if there is more resistance in one circuit than the other while not under load, then the voltage drop will be worse in the circuit with more resistance.
@@FullThrottleRC it might be up to a certain amperage. Tiny wire might have less resistance but the bigger one will have a lot less voltage drop under load.
Your test is flawed. Your xt90 test goes through both male and female connectors. Your bullet test is only going through one side of the complete bullet connection.
That's because the amperage from the battery has to pass through both ends of the xt90 connector while using the bullet connectors, they plug straight into the battery. If I was just replacing the xt90s with a male and female bullet connector then you'd be correct, but the bullet connectors are plugging directly into the battery where the xt90s would have to plug into the same place in the battery and then pass through both male and female ends of the xt90 connectors. Hope that clears it up.
@@FullThrottleRCThe battery has the "female" side of the connector.