3.5mm RC banana/bullet connectors, female PCB mount? - Page 1
Forum section: electronics / beginners

author: Infraviolet
author_rank: Super Contributor
timestamp: February 25, 2024, 07:24:31 pm
content: Does anyone know if these exist? Female PCB mount through hole connectors to accept Remote Control vehicle style banana/bullet 3.5mm male connectors?This sort of thing exists for the (longer, narrower aspect ratio) 4mm connectors used on multimeters and bench power supplies (examplehttps://uk.farnell.com/multicomp/24-243-1/banana-socket-20a-4mm-pcb-red/dp/1698982), but I can't seem to find it for the short stubby 3.5mm type connectors.I'm setting up a testing board to attach to BLDC motors wich come with the 3.5mm banana/bullet connectors already on the wires, and want to be able to attach them in a removable way, without having to solder the male connectors in to wide plated holes in the board, or having to chop the ends of the motors' wires to it alternative connectors.Does anyone know if 3.5mm female pcb mount jacks are made? And if there's any sellers of them easy to order from in the UK?

author: trilerian
author_rank: Regular Contributor
timestamp: February 25, 2024, 09:11:45 pm
content: I just make 7.5mm x 7.5mm solder pads on my pcb’s and solder standard female 3.5 bullets to them. You can make the pads smaller, but you will need at least 5mm wide.

author: Infraviolet
author_rank: Super Contributor
timestamp: February 26, 2024, 12:15:38 am
content: You mean SMD mounting those tubular female connectors designed for crimping to wires? A banana/bullet connector has quite a burst of force when pushed in or puleld out, would soldering a female to a pad survive repeated connections/disconnections?

author: coppercone2
author_rank: Super Contributor
timestamp: February 26, 2024, 12:17:27 am
content: can you use a mini banana plug instead?

author: Jwillis
author_rank: Super Contributor
timestamp: February 26, 2024, 03:20:34 am
content: SMD mounting is not the best for heavy mechanical connections without some type of anchor to the PCB. The traces simply can't take that type of repeated mechanical use. So you will find that all mechanical connections that require constant force will have some kind of through hole structure. It's not uncommon nor against any rule to mix SMD with through hole components and connectors. Even binding posts can be bolted directly to a PCB.

author: trilerian
author_rank: Regular Contributor
timestamp: February 26, 2024, 06:19:37 am
content: Quote from: Infraviolet on February 26, 2024, 12:15:38 amNo, the solid brass female connectors. Amass 3.5mm female connectors. I have pushed and pried on them without issues. I use pads and solder XT60 and XT90 connectors on them too. And XT90 connectors can be a pita to pull apart sometimes.

author: Infraviolet
author_rank: Super Contributor
timestamp: February 26, 2024, 06:23:25 pm
content: You mean like the females in this sort of set?https://www.amazon.co.uk/Gold-plated-3-5MM-Banana-Connector-Battery/dp/B0BK68CQ5G/I've seen pictures of "ESC power distribution" boards which appear to have just soldered these females to large square pads, they also look like they have aligned the little side hole on the female with a hole in the PCB pad, though I'm not sure if it is just solder in there or if they pushed some little piece of wire through the holes before applying solder.

author: MarkT
author_rank: Frequent Contributor
timestamp: February 26, 2024, 08:28:30 pm
content: Quote from: Jwillis on February 26, 2024, 03:20:34 amThrough hole or peg-and-paste.

author: trilerian
author_rank: Regular Contributor
timestamp: February 27, 2024, 02:08:29 am
content: Quote from: Infraviolet on February 26, 2024, 06:23:25 pmI always align the little hole down as well. And yes, those are what I use.However, other more experienced people are saying to do something different, maybe that is what the hole is for, some sort of anchor. I've also seen it where the pcb is cut around the part and the pad goes to both sides and you solder it in between. For me, I via stitch the pads together on both sides.

author: trilerian
author_rank: Regular Contributor
timestamp: March 30, 2024, 02:58:40 pm
content: I wanted to revisit this thread in case the OP was still looking for ideas. I have found through hole XT60PW connectors that sever the purpose here. I have moved my designs using XT60 and XT90 to the PW versions. However the XT90PW are hard to get, I was able to get a hold of the XT60PW rather easily through Amazon. The female XT60PW is just the tubular 3.5mm connector in a plug. The footprint was already in Kicad as well. Granted for the BLDC motor you would need 2 connectors, which would be 4 plugs to it may not be the most elegant solution, but it fulfils the requirements of having a post going through the board that other posters were recommending.

author: Infraviolet
author_rank: Super Contributor
timestamp: April 13, 2024, 06:56:51 pm
content: Here's the two ways I came up with in the end:Way 1 uses a through hole sized to be wide enough to take the entry end of the connector, but narrow enough to catch on the wider back section of the connector. The connector is slid in 1A/1B, with solder applied to one side, allowed to cool, then to the other side, and a blob of bluetack to hold it steady before the first side's joint is done. Pretty messy overall, some solder leaks down the space between the connector's brass body and the sides of the through hole, and it seems that when one uses as much solder as is needed for things this big then truly cleaning off all the flux residue afterward is impossible.Way 2 uses a >7mm x 7mm pad with two holes in it. Two stripped singe core wires are looped through the hole in the back section of the 3.5mm female banana/bullet connector and pushed down through the two holes in the PCB pad (2A/2B). The wires are twisted together below to tighten the connector down, 2C/2D. Then apply solder above (2F) by heating both the pad and the connector. Then cut off the wire ends and solder below (2E) heating both the cut off wire ends and the underside pad. Again, couldn't clean all the flux of (rosin, normal sort not activated or super-activated, flux being from the core of leaded 60/40 solder reel, no extra flux added) however hard I scrubbed with a brush and IPA (99%) or water (tried both alternately).The top left image shows the board with 3.5mm banana wires plugged in to those method 2 connectors.I think method 2 is more promising, and could be strengthened by adding some extra holes in the pad for further wire loops run in other directions (like over the top of the main barrel of the connector) to be run and twisted tight before soldering.EDIT: forgot the image attachement, here it is now