MR69 All-In-One Motor Connector

This is a little something I’m developing. Its an all-in-one motor connector for phase wires and sensor wires.

I just started desiging this, and its still very much a work in progress. Lots of details need to be hammered out, including but not limited to:

  • Final design(s)
  • Connector types and size
  • Housing material and manufacturing method
  • Assembly method
  • Price

Yes, I intend to sell these. No, I dont have an estimate on when I can sell you a set :joy: I also intend to release the 3D files when I have come to a more finalized design. If you are interested in beta-testing and you have a 3D printer (or live in the contiguous United States and will pay shipping for a small envelope) then feel free to let me know in this thread.

I’ll be 3D printing the first prototypes today :blush:

Im in desperate need of feedback here, so please chime in with all the ways you think this will fail! :smiley:

2020.10.1 Project update:
Officially caved to peer pressure and renamed these connectors to MR69 (because its an MR60 with 9 pins total). Blame @Jujo for explaining the joke to me.


How small do you intend on making the small bullets? Any chance heat could cause them to come into close contact or touch after a disconnection?


Oh bro, I wanna help in anyway I can!
What kind of pins will you be using?


I would suggest building a simple PCB with these connectors in their configuration. The PCB hold the pins in place but doesn’t actually connect anything. Then 3d print the housing and glue them together.
This way you don’t need to mount the pins to the 3d printed housing. And you can order the PCB with pins already soldered on in bulk for a few fractions of a $ a pop. Say from jlcpcb

I’d be happy to help build that pcb file of you’re interested.


That sounds like an awesome alternative :grin:



Do eeet.

Really solid suggestion.

Might have to make it slightly larger to gain clearances for the copper ring-pads around each individual bullet though yeah?


I could easily live with that in exchange for less connectors coming out of my stormcore case :stuck_out_tongue:


The hard part will be sourcing plugs that are the right size.


I would make these larger than the standard bullets in the MR60, maybe this can be a MR90 with 6 pins instead :slight_smile:


does anyone know the mfrs rating for connects/reconnects of bullets? especially the small 1.5mm bullets?
Thanks Robin, 2000 connections for both 3.5 and 4mm versions, if the 1.5mm has 25% of that I’ll be fine as frog hair @agressivstreetlamp

(yeah I know that isn’t your design requirements, but I’m poaching on your science)

I’m thinking for use as an external BMS connection, I’d guess at mostly charging without balancing 90% of the time, and only bring the battery up to full voltage and balance it, like, once a week… at a two year battery life, that’s like ~100 connects, and that seems completely acceptable.

anecdotal evidence, I’ve flown MR30s/MR60s mounted to qwads with 1000s of reconnects and yeah they get a bit looser, they still all work acceptably in high amp draw requirements… in a low amp BMS balancing scenario I don’t think this is an issue…


sort of what @kook and @Minimadness are on about,

how about one of these? 4mm instead of the 3.5mm that mr60s usually iuse

fun fact, this is exactly what trampa slings and i totally didn tknow until i put the lcsc part # into google

data sheet for both 3.5 and 4mm versions


Al, posted a link for 0.8mm bullets, and they’re like cheep as fukk, but they appear in the pix as they are VERY long!!!

another link that came up with a myriad of bullets and bullet sizes but they’re spendy

and the male solder end looks kinda weird, almost looks like a crimp connector?? :crazy_face:

these look like they hit the “goldilocks zone” small and pretty cheep…

they’re even from the robot-shop


Ill look into these, but at the end of the day, if lscs doesnt stock them, then it may not be cost effective


Currently I have 2mm bullets, but I just ordered some 0.8mm bullet connectors to play around with. These might be the better option.

Hopefully not. This is what testing is for though :smile: I am considering lots of different options for material choice, and heat resistance is my #1 criteria (followed closely by strength and resilience, etc.).

This first design is using 4mm Amass bullets and 2mm generic bullets. I will likely be switching to 0.8mm bullets for the next revision.

This would be awesome, but hopefully not needed. We will see how the testing goes!

4mm bullets as stated above, which are bigger than the 3.5mm bullets in an MR60 :wink:

Thats up next :grin:

GX20-14 is what you need here :kissing_heart:

Here are the results of my first print. Clearly I was a little over ambitious with how small I could make these haha. v2 is imminent.


yeah the MOQs and pricing structure @Benjamin and I are dealing with are completely different… I’ll be dealing with much less than a 100 for a start


If you want me to run test prints or help in any way just let me know…besides actually installing and riding with it yet…


good stuff. im actually wondering if there is a fundemental flaw in my suggestion as theres a decent chance that the fab house wont be able to populate these bullet connectors onto a pcb. So you’d still have to do it by hand.


yeah, it’s in consideration, as is bumping out the beautiful eBoosted enclosure and just running a Daly inside… I’m pretty fluent in small fiddly solder connections, but those always look EXTREMELY fiddly and frustrating…

perhaps I should just save the bux of reinventing the wheel, and just buy a couple and solder it up…

the worst part is, I don’t know if that would actually help with the internal enclosure space…


You know you have young children when the first thing you notice is Mickey mouse :man_facepalming:

What about a resin printed version? Better details for smaller prints?


Stop considering. Its the right tool for the job :joy: If you can drill a 19mm hole in your enclosure, then you can use the GX20-14.

Its seriously was not as bad as I was expecting. Tin each pin, and the wires, then press them together with a hot iron. Bingo bango. Took me like less than 30 minutes per side, and I work slow as fuck.