Originally Posted by Wintr

An electronics shop near me sells 4mm bullets in two different lengths, one the same as you commonly find in RC gear, the other just over half as long. Something to watch for, when shopping for them.

Good to know. I'd imagine that there are so few makers of bullet connectors in this hobby that we usually don't encounter different depths. The ones we all use probably come from the same factory.

Wintr and zeezee,
That's the first I've heard about different 4mm lengths. Do you know what the different manufacturers are, so that maybe I can look into this myself? I'm guessing that it's OK to mix a short male with a long female, as long as you don't pull too many amps for the male side. I wonder if the amp ratings are even that much different anyway.

Capt. Crunch,
Yes, I think 3.5mm bullets will be the size for me. I'm don't think I'm pulling more than 15 amps yet. (If I do need more current in the future, I'll standardize the even larger batteries to maybe 5mm. But no worries about that for now.) I'm assuming 3.5mm bullets are as readily available as the other sizes?

eagle777,
Thanks for the concern. But like I said, I have the short problem covered.

ChillPhatCat,
That's interesting. You know, they all do look pretty much exactly the same, don't they?

Originally Posted by 01011010

4. Do you think it's a good idea to use bullets for battery-ESC connections? Why? I don't care if you think "Deans are the best", or even "bullets are awesome". Connector wars are useless to me and everyone else reading this. Tell us why. But don't say it's easier to unplug.

This is rather confusing to me (nothing new in that respect, though... )

If two connectors are equally capable of carrying current efficiently, then why would ease of plugging need to be thrown out as a deciding factor?

Chuck

Chuck, some connectors (with Deans being the poster child) can be so hard to unplug that you risk yanking the leads and breaking stuff, especially if they come unstuck very suddenly. I do use Deans plugs and I've solved the problem, but a lot of people continue to grab them by the wires and just hammer away till they separate. Obviously not a good idea...

I think soldering difficulty for beginners a big part of the problem with Deans, though. If heat is applied too long, the plastic will warp a bit and make them way harder to separate than necessary.

Things like bullets can be all over the map. I've had some that might as well be soldered once they're plugged together, while others literally fall apart if the wire shifts a bit... I haven't messed with anything else, really. I've got Deans down to an art and I like them a lot.

Originally Posted by 01011010

Wintr and zeezee,
That's the first I've heard about different 4mm lengths. Do you know what the different manufacturers are, so that maybe I can look into this myself? I'm guessing that it's OK to mix a short male with a long female, as long as you don't pull too many amps for the male side. I wonder if the amp ratings are even that much different anyway.

The shop sells them by the piece, or small package mates. No labels, so no indication of source. Since current rating should be a function of contact surface, the current ratings should be different, but, again, no labels.

After the current issue (who said 3.5mm are only good to 15 A?, I use them to 50A all the time), the next deciding area would be ease of use. As noted above, some low quality bullet/banna conns of non-standard diameters, 1-2.5mm, are too tight and some are too loose, avoid them at all costs. I've been using 4mm and 3.5mm bannas for over 12 years, only once have I got a set of 3.5s that were both too tight & too loose, they were from a batch from China. Never seen them again, the market took care of them very nicely.
Although not mentioned, the non-gold plated conns are for small children's toys and cheap household appliances, not for more than 1 amp at best! The tin or zink plating wears out very fast, and the springyness of the metal is soon gone too, ask the car guys about the Tamaiya plugs!

One thing about 4mm is that they are the standard Banna connectors for electronics, and as such the supply chain has many of them in various styles of shanks and fittings, all of very high quality, even at Radio Shack.

As I said, I prefer the 3.5 mm in most applications as they are easy to solder, plug & unplug, and acceptable pricing. They must be polorized and insulated by the user, so if this puts you off, don't go that way, get something else. There are many choices out there.

As for T Conns, originally made by Deans and called Ultra Connectors, the Chinese knock-offs are terrible and provided free of cost on LiPo battery packs, if you can tollerate them so be it, go use the heck out of them, they are nicely polorized and will carry a lot of current, 100A+ in bursts.

For F5B and other Very, Very High currents 300+ Amps!, 6 mm are the only way to go, they won't heat up and the solder won't melt and let the wire fall out! They are difficult to work with in every way, not for the in-experienced at all.

Hope this helps,

Crunch

Originally Posted by NoFlyZone

...why would ease of plugging need to be thrown out as a deciding factor?

I guess that would be sort of confusing. What I mean is this. Don't use ease of unplugging as your main argument. I want to know other reasons as well, because the "plugging sensation" is only a small part of the whole story.

Originally Posted by C₄H₁₀

Things like bullets can be all over the map. I've had some that might as well be soldered once they're plugged together, while others literally fall apart if the wire shifts a bit.

Uh oh. Is it common for different manufacturers' bullets not to fit together properly? Has anyone else had this problem?

Originally Posted by Wintr

The shop sells them by the piece, or small package mates. No labels, so no indication of source.

Aww, man. Ok.

Originally Posted by Wintr

Since current rating should be a function of contact surface, the current ratings should be different, but, again, no labels.

I would guess the same. But of course it doesn't say.

Originally Posted by 01011010

I guess that would be sort of confusing. What I mean is this. Don't use ease of unplugging as your main argument. I want to know other reasons as well, because the "plugging sensation" is only a small part of the whole story.

This is even more confusing. If two different connectors can carry the required current for my application, then the deciding factor for me is...

1) Ease of fabrication

2) Ease of usage (how easy they are to plug into each other)

What other variables can be introduced into the equation?

Originally Posted by Capt. Crunch

...who said 3.5mm are only good to 15 A?, I use them to 50A all the time...

Whoops, I'll clarify. I mean that my planes aren't going to pull more than 15A. Thus, I won't be needing any larger than 3.5mm until I upgrade to something like 50-70A. (That is, if I upgrade.)

Originally Posted by Capt. Crunch

...only once have I got a set of 3.5s that were both too tight & too loose...Never seen them again, the market took care of them very nicely.

I see. So, as long as we avoid the really cheap smaller ones, we're OK. Does anyone else agree/disagree?

Originally Posted by Capt. Crunch

One thing about 4mm is that they are the standard Banna connectors for electronics, and as such the supply chain has many of them in various styles of shanks and fittings...

This is why I was considering 4mm ones. I thought maybe they were more "standard" than 3.5s. As for these "various styles of shanks and fittings"... you don't mean the actual metal connector, right? You're just talking about the plastic harnesses? (Sorry, I just want to be clear.)

I suppose for a modeler with an established connector infrastructure, another factor would be plug compatibility... Which is a no-brainer.

I do know that I mostly fly planes where something like an XT60 or EC3/5 would be too physically big to fit in the fuselage. The only thing smaller than Deans that I've found is 3.5mm bullets, but I don't like them due to possible shorts... But for most applications, the size of the connector probably doesn't matter all that much.

Price? Doubt it. Really, if you can't afford connectors....

Originally Posted by NoFlyZone

What other variables can be introduced into the equation?

For me, at least these things are factors:

- Will it handle the job?
- Is it a set standard?
- How long will it last? What happens as it ages?
- Is it a good idea to use it for the given application? Does it make sense?
- Is it safe to use? (Haha, yeah. I said that.)
- Can I get it from various manufacturers? Am I going to get "monopolized", so to speak? (Forget the knockoffs.)
- Is it easy to use? Is it practical?

Originally Posted by 01011010

For me, at least these things are factors:

- Will it handle the job?
- Is it a set standard?
- How long will it last? What happens as it ages?
- Is it a good idea to use it for the given application? Does it make sense?
- Is it safe to use? (Haha, yeah. I said that.)
- Can I get it from various manufacturers? Am I going to get "monopolized", so to speak? (Forget the knockoffs.)
- Is it easy to use?Is it practical?

Actually, that's exactly the requirement I listed earlier; that you said I couldn't list as a reason for using it.

I use EC3s on everything using 1300mah batts and larger.
JSTs are on the smaller batts.
I have never had an issue with pulling apart EC3s. I do put in the female bullets (on the battery power leads) a small amount of white lithium grease (using a tooth pick) every new battery.
EC3s are very easy to solder using a piece of wood with small holes drilled to hold the bullets during the soldering process.
I have never had a cold solder issue on my solder connections. I have had factory cold solder issues on a new airplane.