Molex 51005 / 51006 Connector: Complete Guide to Specs, Pinout, Part Numbers & RC/FPV Applications
If you've ever worked on an RC car, FPV drone, LiPo battery pack, or compact embedded system, you've almost certainly encountered the Molex 51005 / 51006 connector series — even if you didn't know it by name. This 2.0mm pitch wire-to-board system is one of the most widely deployed micro-connector families in the hobby electronics and light industrial world, yet comprehensive technical documentation written for engineers and makers is surprisingly scarce.
This guide fills that gap. We cover everything: mechanical specs, part number decoder, pinout conventions, compatibility with JST PH, crimping requirements, and real-world application scenarios — structured to answer both the quick lookup questions and the deeper engineering decisions.
What Are the Molex 51005 and 51006 Connectors?
The Molex 51005 and Molex 51006 are complementary halves of a 2.0mm pitch, single-row, wire-to-board crimp connector system:
- Molex 51005 — the receptacle housing (female, wire side). This is the plug that attaches to the wire harness.
- Molex 51006 — the PCB header (male, board side). This is the through-hole or SMT header soldered onto the PCB.
Together they form a mated pair. The 51005 receptacle locks onto the 51006 header via a friction/latch mechanism, creating a secure, low-profile connection suitable for space-constrained assemblies.
This series is part of Molex's broader Micro-Losi / 2.0mm Crimp Connector family, sometimes referred to informally as the "Molex 2.0" or "Molex Micro" connector in hobby communities.
Molex 51005 receptacle housings (2–5 pin) alongside Molex 50058 crimp terminals on carrier strip. The white nylon housings accept pre-crimped terminals inserted from the rear.
Key Specifications at a Glance
| Parameter | Molex 51005 (Receptacle) | Molex 51006 (Header) |
|---|---|---|
| Pitch | 2.00 mm | 2.00 mm |
| Number of Circuits | 2 to 15 | 2 to 15 |
| Current Rating | 1.0 A per contact | 1.0 A per contact |
| Voltage Rating | 250 V AC/DC | 250 V AC/DC |
| Contact Material | Phosphor bronze, tin-plated | Brass, tin-plated |
| Housing Material | Nylon 66, UL 94V-2 | Nylon 66, UL 94V-2 |
| Operating Temperature | -25°C to +85°C | -25°C to +85°C |
| Wire Range | AWG 22–30 (0.05–0.34 mm²) | — |
| Mating Cycles | 30 minimum | 30 minimum |
| Mounting Style | Wire harness | Through-hole (TH) |
| Locking | Friction lock | — |
Note: Always verify against the official Molex datasheet for your specific part number, as sub-variants may differ.
Molex 51005 Part Number System Decoded
Molex part numbers for the 51005 series follow a consistent pattern. Understanding the decoder saves significant time when sourcing:
51005-02xx — 2-circuit receptacle housing
51005-03xx — 3-circuit receptacle housing
51005-04xx — 4-circuit receptacle housing
...
51005-15xx — 15-circuit receptacle housing
The most commonly searched and stocked variants include:
- 51005-0200 — 2-pin receptacle (the most popular, used in RC/LiPo battery connectors)
- 51005-0300 — 3-pin receptacle
- 51005-0400 — 4-pin receptacle
- 51005-0500 — 5-pin receptacle
- 51005-0600 — 6-pin receptacle
For the 51006 header series:
- 51006-0200 — 2-pin PCB header (through-hole, right-angle or vertical)
- 51006-0300 — 3-pin PCB header
- 51006-0400 — 4-pin PCB header
- 51006-0500 — 5-pin PCB header
Molex 51005 housings in 2-pin through 8-pin configurations (bottom rows) alongside two variants of the Molex 50058 crimp terminal strip (top). Note the progressive width increase with each additional circuit.
The crimp terminal used with the 51005 housing is the Molex 50058 series (for AWG 22–28) or Molex 50079 (for finer wire gauges). Always match the terminal to your wire gauge — using an oversized terminal on thin wire is the single most common cause of intermittent connections in field assemblies.
Pinout and Polarity
The Molex 51005/51006 system does not enforce electrical polarity through asymmetric housing geometry alone — unlike JST connectors which use a keyed tab. Instead, polarity is maintained by:
- Pin 1 marker on the PCB silkscreen (typically a square pad or triangle indicator)
- Wire color convention in the harness (red = positive, black = ground in most RC/battery applications)
- Latch orientation — the latch tab on the 51005 receptacle faces a specific direction relative to pin 1
For the ubiquitous 2-pin (51005-0200 / 51006-0200) configuration used in RC battery applications:
| Pin | Function (RC/Battery) | Wire Color Convention |
|---|---|---|
| Pin 1 | Positive (+) | Red |
| Pin 2 | Negative / Ground (−) | Black |
Molex 51005-0200 2-pin pigtail cables: red wire = Pin 1 (positive), black wire = Pin 2 (negative/ground). The upper connector shows the open mating face; the lower shows the wire-entry side. This is the standard wiring convention for RC/LiPo battery applications.
Critical warning: Reversing polarity on a LiPo battery connection using this connector will immediately damage the ESC or receiver. Always verify pin 1 orientation against the PCB silkscreen before mating.
Molex 51005 vs JST PH 2.0mm: Are They Compatible?
This is the single most frequently asked question about the 51005 series, and the answer requires nuance:
Pitch: Both use 2.0mm pitch — so the pin spacing is identical.
Physical mating: They are NOT directly intermateable. The housing geometry, latch mechanism, and contact dimensions differ between Molex 51005 and JST PH.
Adapter cables: JST PH to Molex 51005 adapter cables are widely available and commonly used in RC/FPV to bridge between different manufacturer ecosystems.
The confusion arises because both connectors appear visually similar at 2.0mm pitch and are used in overlapping application spaces (RC batteries, small electronics). However, attempting to force-mate them risks damaging both connectors and creating an unreliable connection.
Molex 51005/51006 (left) vs JST PH 2.0mm (right): identical pitch, incompatible housings. The Molex 51005 uses a friction latch with a distinctive tab profile; the JST PH uses a positive latch with a different housing outline. Do not attempt to force-mate these connectors.
| Feature | Molex 51005/51006 | JST PH 2.0mm |
|---|---|---|
| Pitch | 2.00 mm | 2.00 mm |
| Direct Compatibility | ❌ Not intermateable | |
| Housing Lock | Friction latch | Positive latch |
| Current Rating | 1.0 A/contact | 2.0 A/contact |
| Wire Range | AWG 22–30 | AWG 24–32 |
| RC/FPV Use | Very common (Micro Losi) | Very common (JST standard) |
| Adapter Available | ✅ Yes, widely available | |
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RC and FPV Applications: Why the 51005 Dominates
The Molex 51005/51006 connector — known in the RC hobby world as the "Micro Losi" or "Molex Micro" connector — became the de facto standard for small-scale RC vehicles and micro FPV drones for several reasons:
1. Compact Form Factor
At 2.0mm pitch with a low-profile housing, the 51005 fits into micro RC receivers, flight controllers, and ESCs where larger connectors like Deans or XT30 would be impractical.
2. Adequate Current Capacity
For micro brushed motors and small brushless setups drawing under 5A total (1A per contact × 2 contacts = 2A for a 2-pin connector), the 51005 provides sufficient current handling without the bulk of higher-rated connectors.
3. Ecosystem Lock-In
Brands like Horizon Hobby, Tower Hobbies, and numerous micro RC manufacturers standardized on this connector for battery packs, making it the dominant format for 1S and 2S LiPo batteries in the micro RC segment.
4. Common RC Applications
- 1S and 2S LiPo battery connectors for micro RC cars and trucks
- Micro FPV drone battery leads (particularly older Inductrix/Blade-style quads)
- RC receiver power inputs
- Micro brushed ESC battery connections
- Charger balance lead adapters
If you're searching for "molex 51005 z" in the FPV context, this refers to the Blade Inductrix Z series micro quad, which uses the 51005-0200 as its battery connector — a very common replacement/upgrade part.
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Industrial and Embedded Applications
Beyond RC/FPV, the 51005/51006 series sees significant use in:
- Consumer electronics: Internal wiring harnesses in compact devices where space is at a premium
- Medical devices: Low-current sensor connections in portable diagnostic equipment
- Automotive accessories: Interior lighting and sensor connections in aftermarket modules
- Industrial control panels: Signal-level connections between PCBs in compact DIN-rail modules
- IoT devices: Battery connections in wireless sensor nodes and beacon hardware
The 1A per contact rating makes this series appropriate for signal and low-power applications. For higher current requirements (>3A), consider the Molex Micro-Fit 3.0 or Molex Mini-Fit Jr. series instead.
How to Crimp Molex 51005 Connectors
Required Tools and Materials
- Crimp tool: Molex Part No. 63811-1000 (hand crimp tool) or equivalent ratcheting crimp tool with 2.0mm die
- Terminals: Molex 50058-8000 (AWG 22–28) or 50079-8000 (AWG 26–30)
- Wire stripper: Set to strip 2.5–3.0mm of insulation
- Terminal extraction tool: For rework and pin removal
Step-by-Step Crimping Process
- Strip the wire: Remove 2.5–3.0mm of insulation. Do not nick the conductor strands.
- Position the terminal: Place the Molex 50058 terminal in the crimp tool die. The insulation crimp wings face up.
- Insert the wire: Slide the stripped wire into the terminal until the conductor is fully seated in the conductor crimp area and the insulation sits in the insulation crimp area.
- Crimp: Squeeze the ratcheting crimp tool fully until it releases. Do not release mid-crimp.
- Inspect: The conductor crimp should show a slight bell-mouth flare. Pull-test with approximately 10N force — the wire should not pull free.
- Insert into housing: Push the crimped terminal into the 51005 housing from the rear until you hear/feel a click. The terminal retention lance engages the housing.
- Verify seating: Gently tug each wire to confirm the terminal is locked.
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Common Crimping Mistakes
- Under-crimping: Insufficient force leaves the conductor loose, causing intermittent connections under vibration (critical failure mode in RC/FPV)
- Over-crimping: Crushes the terminal, cutting conductor strands and reducing current capacity
- Wrong terminal for wire gauge: Using AWG 22 terminals on AWG 28 wire creates a loose crimp that will fail
- Insulation in conductor crimp zone: Prevents proper electrical contact
Sourcing Guide: What to Look For
When sourcing Molex 51005/51006 connectors, you'll encounter several naming conventions across different suppliers:
| Common Name | Molex Part Number | Notes |
|---|---|---|
| Micro Losi 2-pin female | 51005-0200 | Most common RC battery connector |
| Micro Losi 2-pin male header | 51006-0200 | PCB-mount counterpart |
| Molex 2.0mm 3-pin housing | 51005-0300 | Common in sensor harnesses |
| Molex 2.0mm 4-pin housing | 51005-0400 | Used in small motor/LED drivers |
| Molex 2.0mm crimp terminal | 50058-8000 | For AWG 22–28 wire |
| Molex 2.0mm crimp terminal (fine) | 50079-8000 | For AWG 26–30 wire |
Quality Indicators When Buying
Molex 51005 housings in various pin counts. Inspect the latch tab geometry and housing squareness — quality housings have clean mold lines and consistent tab height. Warped or flash-heavy housings indicate poor tooling and may cause mating issues.
- Housing color: Genuine Molex 51005 housings are natural (off-white/cream). Third-party equivalents may be white or black — functionally equivalent if dimensions match.
- Terminal plating: Tin-plated contacts are standard. Gold-plated variants exist for high-reliability applications but are rarely necessary for RC/hobby use.
- Dimensional accuracy: Low-quality clones may have slightly off-pitch housings that cause mating issues. Source from reputable distributors (Mouser, DigiKey, LCSC) or trusted specialty suppliers for critical applications.
Frequently Asked Questions
Q: What is the difference between Molex 51005 and 51006?
The 51005 is the wire-side receptacle (female housing that attaches to your wire harness), while the 51006 is the PCB-side header (male pins soldered to the circuit board). They are designed to mate with each other.
Q: Is Molex 51005 the same as JST PH?
No. Both use 2.0mm pitch, but they are not directly intermateable. The housing geometry and contact design differ. Adapter cables are available if you need to connect the two systems.
Q: What wire gauge should I use with Molex 51005?
The 51005 accepts AWG 22–30 wire. For RC/LiPo battery applications, AWG 26–28 silicone wire is the most common choice, balancing flexibility with adequate current capacity for the 1A/contact rating.
Q: Can I use Molex 51005 for LiPo batteries?
Yes, for low-current applications (micro RC, 1S/2S packs with brushed micro motors drawing under 2A total). For higher-current LiPo applications (3S+, brushless motors), use a higher-rated connector such as XT30 or XT60.
Q: What is the "Molex 51005 Z" connector?
In FPV/RC communities, "51005 Z" refers to the Molex 51005-0200 connector used on the Blade Inductrix Z and similar micro quad battery packs. It's the same 2-pin 51005 connector — the "Z" refers to the drone model, not a connector variant.
Q: How do I remove a terminal from a Molex 51005 housing?
Use a terminal extraction tool (a thin, flat pick or the Molex extraction tool for this series). Insert it from the mating face of the housing to depress the retention lance, then pull the wire from the rear. Avoid using sharp metal tools that could damage the housing or lance.
Q: What is the mating force for Molex 51005/51006?
Typical mating force is approximately 0.3–0.5N per contact. For a 2-pin connector, expect roughly 0.6–1.0N total insertion force — light enough for tool-free mating in field conditions.
Q: Are there SMT versions of the 51006 header?
The standard 51006 is a through-hole header. Molex offers surface-mount alternatives in the same 2.0mm pitch family — check the Molex product series chart for SMT-compatible part numbers if your PCB design requires it.
Q: What is the 50012/50013 series in relation to 51005/51006?
The Molex 50012 and 50013 are an older, related 2.0mm pitch connector family. The 51005/51006 series is the more modern successor with improved retention and a wider circuit count range. Some suppliers list them together ("50012 50013 51005 51006 series") as they share the same pitch and general application space.
Q: Where can I buy genuine Molex 51005 connectors?
Authorized distributors include Mouser Electronics, DigiKey, and Arrow Electronics. For smaller quantities and hobby use, specialty electronics suppliers often stock pre-assembled pigtails and connector kits. We stock Molex MX 2.0mm Connector Kits with pre-crimped cables ready to ship.
Molex 51005/51006 vs Other Molex 2.0mm Series
Molex produces several connector families in the 2.0mm pitch range. Here's how the 51005/51006 compares to its closest relatives:
| Series | Pitch | Current | Rows | Primary Use |
|---|---|---|---|---|
| 51005/51006 | 2.0 mm | 1.0 A | Single | RC/FPV, light industrial |
| 50012/50013 | 2.0 mm | 1.0 A | Single | Legacy, same application space |
| PicoBlade (51021) | 1.25 mm | 1.0 A | Single | Ultra-compact, high-density |
| Mini-SPOX | 2.5 mm | 3.0 A | Single | Higher current wire-to-board |
| KK 254 | 2.54 mm | 3.0 A | Single | PCB prototyping, Arduino |
| Micro-Fit 3.0 | 3.0 mm | 5.0 A | Dual | Power distribution |
Selection Guide: Is Molex 51005/51006 Right for Your Application?
Use this decision framework to determine if the 51005/51006 is the right connector for your project:
✅ Choose Molex 51005/51006 if:
- Your current requirement is ≤1A per contact (≤2A for 2-pin)
- You need a compact 2.0mm pitch connector for a space-constrained PCB
- You're working in the RC/FPV ecosystem where Micro Losi is the standard
- Your operating temperature stays within −25°C to +85°C
- You need AWG 22–30 wire compatibility
- You require 30+ mating cycles (standard service life)
❌ Consider alternatives if:
- Current exceeds 2A total → use Mini-SPOX or XT30
- You need higher mating cycle life (>30 cycles) → use gold-plated contacts or a higher-spec series
- Your environment involves significant vibration without strain relief → add a cable clamp or use a locking connector variant
- You need IP-rated sealing → this series is unsealed; use a sealed connector family
Summary
The Molex 51005/51006 connector system is a mature, well-proven 2.0mm pitch wire-to-board solution that has earned its dominant position in RC/FPV hobby electronics and compact embedded applications. Its combination of small footprint, adequate current capacity, and broad ecosystem support — particularly in the Micro Losi RC battery standard — makes it a go-to choice for engineers and makers working at the micro scale.
Key takeaways:
- 51005 = wire-side receptacle; 51006 = PCB-side header
- 2.0mm pitch, 1A per contact, AWG 22–30 wire range
- Not directly compatible with JST PH despite identical pitch — use adapter cables to bridge systems
- The 2-pin variant (51005-0200 / 51006-0200) is the dominant RC/LiPo battery connector in the micro segment
- Crimp with Molex 50058 terminals and a proper ratcheting crimp tool for reliable connections
- Source from authorized distributors for critical applications; hobby-grade clones are acceptable for non-critical RC use
Whether you're replacing a worn battery connector on a micro RC car, designing a new IoT sensor node, or building a custom wire harness for a compact embedded system, the Molex 51005/51006 series delivers reliable performance in a package that punches well above its size.
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