battery contector

Author

eonist commented Mar 14, 2026

the down tube is not always open. it open when you charge your bike. that's it. okay. I guess we can reseed the pogo pins in a dock style design. that avoids water issue and safety issue

Author

eonist commented Mar 14, 2026

Makes sense, and that changes the constraints a lot in your favour.

If the downtube is only open when you actively pull the battery for charging, then:

Water exposure is limited (mostly riding with the tube closed), so you don’t need full “open in a storm for months” robustness.
Safety can be handled by recessing and partially shrouding the pogo pins in a dock-style pocket at the bottom of the tube.

Dock-style pogo design (refined)

Frame has a small recessed dock at the downtube floor, like a shallow rectangular cup.
Pogo pins are mounted on a small PCB at the vertical walls or sloped floor of this dock, not flush at the opening.
Battery scaffold bottom has a matching plug shape that drops into the dock and pushes against the pins.
Dock walls and a narrow opening mean fingers can’t reach the pins; water that enters drains out through a small hole.

This way:

When the battery is removed, the dock is a small, mostly enclosed pocket that sheds water and hides the pins.
When the battery is inserted, pogo pins get clean, wiping contact, but they’re never just sitting exposed at the bottom of a big cavity.

If you want, I can now sketch a minimal spec for that dock geometry (depth, opening size, pin positions) tailored to your current scaffold footprint.

Author

the down tube has the elevated pogo pad part. this way water just slides over it. no pooling. drains in the bottom of down tube. the battery has the receded dock part with pins. receding solves safety. the doc design also aligns the docking

Author

eonist commented Mar 14, 2026

Here’s a compact, CAD‑ready sketch in words.

1. Overall dock geometry (frame side)

Location: Machined pocket at the very bottom of the downtube (inside, above BB area).
Pocket opening (at tube interior):
- Width (X): 26 mm
- Depth (Y): 18 mm
Pocket depth (Z, downwards from tube interior): 14 mm

Think of it as a small rectangular “cup” inside the tube that the battery tip drops into.

Walls: 2 mm thick all around.
Floor: 2 mm thick, with a 2 mm drain hole at the lowest point (to outside world).

2. Contact block inside the dock

Inside that pocket sits a simple pogo‑pin block:

Block size: 22 × 14 × 10 mm (W × D × H).
Position: Centered in the pocket, sitting on the floor; top of block is 4 mm below the pocket opening.

So when you look down the empty downtube, you see a rectangular hole; 4 mm down, you see the top of a small block — not bare pins.

Pogo pin layout (example 5‑pin)

On the top face of the block:

Two power pins (3 mm barrel) near the sides.
Three signal pins (1.5–2 mm) in the middle.

Coordinates (relative to block center, in mm):

Power +: (−7, 0)
Power −: (+7, 0)
Signal 1: (−3, 0)
Signal 2: (0, 0)
Signal 3: (+3, 0)

All pogo pins protrude ~1.5 mm above the block surface at rest.

3. Battery-side plug geometry (scaffold bottom)

The scaffold bottom gets a matching plug that drops into the dock:

Plug boss: 24 × 16 × 10 mm (W × D × H), centered on scaffold bottom.
Chamfer: 1 mm 45° chamfer on lower edges for lead‑in.

When fully inserted:

Plug boss slides into the 26 × 18 mm pocket with 1 mm radial clearance.
Boss bottom stops 1 mm above the pocket floor (so it doesn’t crush the block).
The plug’s contact pads on its underside sit directly over the pogo pins.

Contact pads on plug

On plug bottom face:

5 rectangular pads, 4 × 6 mm each, centered over the pogo pin positions above.
Pad surface is flush with plastic, maybe recessed by 0.1 mm so they don’t scrape.

When you drop the battery in, last ~3 mm of travel compress the pins by ~1 mm and create the wiping action.

4. Safety & water behaviour

With the battery removed, pins are 4 mm below the pocket lip, inside a 26 × 18 mm opening — hard to reach even with a finger; impossible to short accidentally with a coin unless you actively poke.
Any water that runs down the tube hits the pocket walls, then runs to the floor and out the 2 mm drain hole. It doesn’t sit on the pins.
You can still make the block from IP67 pogo parts for extra corrosion safety.

If you want, next step I can turn these numbers into a small OpenSCAD module: battery_dock_frame() and battery_dock_plug() that you can integrate into your tube + scaffold models.

Author

eonist commented Mar 14, 2026

That's a really clean inversion. Let me confirm the logic because it's elegant:

The architecture

Why this works so well

Water: the elevated pad island has no cavities for water to pool in — it's just a smooth bump with gold traces. Rain, splash, condensation all slide off and drain down.sameskydevices+1
Safety: pogo pins are buried inside the battery dock. Even if a child sticks a finger into the battery's bottom, the recess depth + narrow pin wells make it nearly impossible to touch live contacts.[johotypro]
Alignment: the dock cavity on the battery slides over the pad island on the frame. The walls of the dock are the guide — no separate fins or funnels needed. Last few mm of travel compresses the springs onto the pads.[sunkye]
Cost: high‑current pogo pins (10A each, gold‑plated) run about $0.18–1.40 per pin depending on quantity. A 6‑pin set on a small PCB inside the battery dock = a few dollars total.[alibaba]
Durability: gold‑plated pogo pins handle 10k–100k cycles easily, and the flat pads on the frame side have no wear mechanism at all.attend+1

Pin layout suggestion

For a 36V system at ~10A continuous:

2 power pins (paralleled, 10A‑rated each = 20A headroom)
1 ground pin
1 thermistor / NTC
1 communication (UART TX or one‑wire)
1 spare / ID

The pad island on the frame side is just a small PCB (~20×15 mm) potted onto a raised plastic pedestal. The battery dock is a matching rectangular cavity with a 6‑pin pogo block soldered to its internal PCB.

This is arguably the simplest, cheapest, and most weather‑resilient swappable battery contact system you could build. Want to start dimensioning the pad island and dock cavity for your DT inner diameter?

That's a really clean inversion. Let me confirm the logic because it's elegant:

The architecture

Side	Component	Why
Down tube (frame)	Elevated flat gold pads on a raised "island"	No moving parts, water sheets off the dome, drains to DT bottom. Nothing to corrode or jam.
Battery	Recessed pogo pins inside a dock cavity	Pins hidden deep inside the battery body — finger‑safe even when battery is out of the bike. Dock walls act as the alignment funnel.

Why this works so well

Water: the elevated pad island has no cavities for water to pool in — it's just a smooth bump with gold traces. Rain, splash, condensation all slide off and drain down. sameskydevices
Safety: pogo pins are buried inside the battery dock. Even if a child sticks a finger into the battery's bottom, the recess depth + narrow pin wells make it nearly impossible to touch live contacts. [johotypro](https://www.johotypro.com/pogo-pin-connector/)
Alignment: the dock cavity on the battery slides over the pad island on the frame. The walls of the dock are the guide — no separate fins or funnels needed. Last few mm of travel compresses the springs onto the pads. [sunkye](https://www.sunkye.com/description-of-pogo-pin-connectors.html)
Cost: high‑current pogo pins (10A each, gold‑plated) run about $0.18–1.40 per pin depending on quantity. A 6‑pin set on a small PCB inside the battery dock = a few dollars total. [alibaba](https://www.alibaba.com/showroom/pogo-pin-connector-10a.html)
Durability: gold‑plated pogo pins handle 10k–100k cycles easily, and the flat pads on the frame side have no wear mechanism at all. attend.com

Pin layout suggestion

For a 36V system at ~10A continuous:

2 power pins (paralleled, 10A‑rated each = 20A headroom)
1 ground pin
1 thermistor / NTC
1 communication (UART TX or one‑wire)
1 spare / ID

The pad island on the frame side is just a small PCB (~20×15 mm) potted onto a raised plastic pedestal. The battery dock is a matching rectangular cavity with a 6‑pin pogo block soldered to its internal PCB.

This is arguably the simplest, cheapest, and most weather‑resilient swappable battery contact system you could build. Want to start dimensioning the pad island and dock cavity for your DT inner diameter?

Author

eonist commented Mar 14, 2026

https://www.pogopinsconnector.com/sale-53243888-3a-spring-loaded-contact-connector-6-pin-2-54-mm-pitch-connector-male-and-female.html pogo pins

Author

eonist commented Mar 14, 2026

https://www.accio.com/plp/6-pin-pogo-pin and https://www.accio.com/d/1601276575888?dataSource=Alibaba.com

Author

eonist commented Mar 14, 2026

Let’s pick a concrete 6‑pin pogo block geometry and then size the pad island around it.

Reasonable 6‑pin pogo block assumptions

Since Accio is an aggregator, we’ll assume a standard 6‑pin block like the common 2.54 mm pitch strips (or equivalent): aliexpress

Pin pitch: 2.54 mm (center‑to‑center). [ccpcontactprobes](https://www.ccpcontactprobes.com/sites/default/files/2020-01/CCP-Standard-Pogo-Pin-Connector.pdf)
Pins in a single row (simplest layout).
Pin count: 6 → total length between outer pins ≈ (5 × 2.54 = 12.7) mm.
Contact diameter: ≈ 1.3–1.5 mm barrels. [ccpcontactprobes](https://www.ccpcontactprobes.com/sites/default/files/2020-01/CCP-Standard-Pogo-Pin-Connector.pdf)
Block body length: ≈ 15–18 mm, width ≈ 3–4 mm, height ≈ 6–9 mm typical. johotypro
Current: 1–3 A per pin, 5 A for some heavy‑duty types. connectors-cables

We can refine once you choose an exact part, but this is good enough to size the island and keep clearances realistic.

Pad island dimensions (frame side)

Assume inner down‑tube width at the bottom is at least 30 mm (you can adjust later). Frame‑side island is a small “speed bump” PCB glued or molded onto a plastic pedestal on the DT floor.

Proposed island:

Island PCB footprint: 24 mm (L) × 10 mm (W).
Top surface: gently domed or chamfered edges so water sheds.
Copper pads area: centered strip about 16 mm (L) × 5 mm (W).

Pad pattern (to match 1×6 pogo row):

Row along length, pitch 2.54 mm, 6 pads → ~12.7 mm active length.
Each pad: about 1.5–2.0 mm wide by 2.0–2.5 mm long, with rounded ends.
Outer keep‑out margin: at least 2–3 mm from island edges so water has “gutters” to flow around the pad zone, not over the pad edges.

Height:

Island pedestal height above DT floor: 3–4 mm.
PCB thickness: 1.0–1.6 mm → total ~4–5 mm above the lowest drain point.
DT floor around the island slopes or is cut away so water naturally bypasses the island and runs along the sides.

Clearances:

Shortest distance from live pad edge to DT metal: ≥ 3 mm creepage in air (36–48 V is forgiving, but this leaves margin).
If you pot/overmold the island’s base, you effectively increase creepage along plastic.

Battery dock (pogo side) to match island

Given a 6‑pin row ~12.7 mm long and block ~15–18 mm long:

Dock cavity:

Internal length: 26–28 mm (island length 24 mm + 1–2 mm margin front/back).
Internal width: 12–14 mm (island width 10 mm + 1–2 mm margin).
Depth (from battery bottom opening to pogo contact tips at mid‑stroke): 6–8 mm.
- Enough that fingers cannot reach pins.
- Pogo stroke: design contact at ~1/2–2/3 stroke height; e.g. pins 8.8 mm total, 1–2 mm effective stroke. aliexpress

Guides:

Entry chamfer: dock opening chamfered 30–45° around all edges.
Side clearance: 0.5–0.75 mm per side between island and dock walls → self‑centering funnel but not too tight for tolerances.

Mounting pogo block:

Pogo block soldered to a small internal PCB fixed at the top of the dock cavity.
Vertical offset so at nominal dock engagement, pins compress ~1 mm from free height.

Simple OpenSCAD‑friendly parameters

You can start with something like:

island_len = 24;
island_w = 10;
island_h = 4.5; // pedestal + PCB
pad_pitch = 2.54;
pad_n = 6;
dock_inner_len = island_len + 2;
dock_inner_w = island_w + 2;
dock_inner_depth = 7;
side_clearance = 1;

Then:

Frame: model a cylinder or oval for DT, subtract a channel at the bottom, then add a rectangular “island” solid with filleted/chamfered edges.
Battery: a rectangular cavity with those dock_inner_* dimensions, plus chamfers.

Once you pick a specific Accio 6‑pin module with exact pitch and body size, we can tighten these numbers. Do you know your approximate down‑tube inner width at the bottom (e.g. 28, 30, 32 mm), so we can check that the 24×10 mm island still leaves enough drainage on both sides?

Author

eonist commented Mar 14, 2026

I mean to make a dock design you have to understand basics of docking. the battery part is reseeded. the down tube part is elevated. it's not that hard. the bat part has pogo pins. the downntube elevated part has pads.

Author

eonist commented Mar 14, 2026

You’re right: I inverted the roles and made everything confusing.

For a proper dock:

Battery part is recessed
- On the battery scaffold bottom you have a shallow cavity.
- Inside that cavity sit the pogo pins, pointing upward.
- The cavity walls protect the pins and give lead‑in for docking.
Downtube part is elevated
- At the downtube floor you have a raised boss (a small platform) that sticks up into the battery cavity.
- On top of that boss you have flat pads (no springs).
- When you drop the battery in, the boss enters the battery cavity, and the pads meet the pogo pins.

Mechanically:

Gravity pulls the battery down; the recess makes sure the pins are never exposed when the pack is out.
The elevated boss keeps the frame pads out of any water at the absolute bottom and makes cleaning easy.
Alignment is trivial: cavity walls guide the boss; the last few mm compress the pogo pins and give the wipe.

I flipped that in the SCAD (pins on the block in the pocket, plug above), so the picture you see is wrong from a docking‑mechanics standpoint.

Author

eonist commented Mar 14, 2026

Here’s a very small, self‑contained OpenSCAD snippet that models:

A cylindrical down tube section.
The raised pad island on the inside bottom.
The matching battery dock cavity with pogo block above.

You can paste this into a new .scad file and tweak dimensions.

// Simple demo of pad island + recessed pogo dock
// Units: mm

$fn = 64;

// ---------- Parameters ----------
dt_inner_d   = 30;    // down tube inner diameter
wall_thick   = 2;     // tube wall
section_len  = 60;    // length of shown tube section

island_len   = 24;
island_w     = 10;
island_h     = 4.5;   // pedestal + PCB

dock_depth   = 7;
dock_clear   = 1;     // clearance around island inside dock

pogo_block_h = 3;     // pogo plastic height

// ---------- Main ----------
module down_tube_section() {
    difference() {
        // outer tube
        cylinder(h = section_len, r = dt_inner_d/2 + wall_thick, center = false);
        // inner bore
        translate([0,0,0])
            cylinder(h = section_len, r = dt_inner_d/2, center = false);
    }
}

module pad_island() {
    // Island at bottom inside tube (z = 0 plane is bottom)
    translate([0, 0, 0]) {
        // Use a rounded box as pedestal+PCB
        translate([0, 0, island_h/2])
            rounded_box([island_len, island_w, island_h], r = 1.5);
    }
}

module rounded_box(size = [10,10,5], r = 1) {
    // quick-and-dirty rounded rectangle prism
    hull() {
        for (sx = [-1, 1])
            for (sy = [-1, 1])
                translate([sx*(size[0]/2 - r), sy*(size [reddit](https://www.reddit.com/r/openscad/comments/1lowpyi/designing_connecting_cubes/)/2 - r), 0])
                    cylinder(h = size [hackster](https://www.hackster.io/chloe-hor/building-a-reliable-magnetic-pogo-pin-usb-charging-interface-2efafd), r = r, center = true);
    }
}

// Battery dock cavity that drops over the island
module battery_dock() {
    // We show only the dock “block” here, not the whole battery.
    dock_len = island_len + 2*dock_clear;
    dock_w   = island_w   + 2*dock_clear;

    // Position the dock above the island, leaving some air gap.
    translate([0, 0, island_h + 2]) {
        // Outer block (for visualisation)
        color("lightgray")
        difference() {
            // Solid block representing the battery bottom
            cube([dock_len+6, dock_w+6, dock_depth+5], center = true);

            // Hollow cavity that fits around the island
            translate([0, 0, -1]) // cavity starts a bit above bottom
                cube([dock_len, dock_w, dock_depth], center = true);

            // Simple chamfer / funnel: subtract a slightly rotated hull
            // (kept crude for simplicity)
        }

        // Pogo block “inside” roof of cavity
        pogo_len = island_len - 4;
        pogo_w   = 4;
        translate([0, 0, dock_depth/2 - pogo_block_h/2])
            color("silver")
            cube([pogo_len, pogo_w, pogo_block_h], center = true);
    }
}

// ---------- Assembly views ----------

// Uncomment ONE of these at a time:

// 1) Frame only with island
//rotate([90,0,0]) {
//    translate([0,0,-section_len/2])
//        down_tube_section();
//    pad_island();
//}

// 2) Frame + dock in position
rotate([90,0,0]) {
    translate([0,0,-section_len/2])
        down_tube_section();
    pad_island();
    battery_dock();
}

This is intentionally simple and blocky: it just shows the relationships and clearances. You can now:

Adjust diameters/lengths to match your actual DT and battery scaffold.
Replace the battery_dock() solid with your real battery bottom geometry and fuse this dock into it.

Want me to add a second module that shows just the pad island and its PCB as a 2D projection you can export as DXF for the copper pattern?

Author

eonist commented Mar 14, 2026

that's cool 2 things. 1. only 1 dock and one island. dont make double sets. 2. the island must be square. dont chafer it. and recede the pins way more into the dock. human fingers cant reach it. also make the island smaller. so the dock is narrower. safetysafetysafetysafetysafety

Author

eonist commented Mar 14, 2026

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eonist commented Mar 14, 2026

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eonist commented Mar 14, 2026

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eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!

eonist commented Mar 14, 2026

Uh oh!