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A New Battery for the ATJ 8466 Portable Car Tire Air Pump (Compresseur)

Fleeting

Context

  • Device: ATJ 8466 portable car tire air pump1
  • Current battery: 2x 2000mAh lithium (original, may need replacement)
  • Goal: Find 2 suitable 18650 batteries within €15 budget
  • Key requirement: Minimum 3.5C discharge (7A ÷ 2Ah)2

Battery Specs Needed

  • Capacity: 2000-2600 mAh per cell (used in pairs for 7.4V total)
  • Discharge rate: Minimum 3.5C (7A ÷ 2Ah), ideally 5-10C for safety margin2
  • Voltage: 3.7V nominal per cell (7.4V when paired in series)
  • Form: 18650 flat-top
  • Quantity: 2 cells (required for ATJ 8466)1
  • Power: Device draws 50W maximum3

Options Compared

XINLANTECH 5200mAh 1s2p (€16.99) — Amazon.fr4

  • Specifications: 5200mAh total (1S2P = 2 cells parallel)5
  • Discharge: 5C (~10A max)6 — too low for compressor
  • Verdict: ❌ Insufficient

JESSPOW 3000mAh 30A (€28.79/4 cells) — Amazon.fr7

  • Specifications: 3000mAh, 30A continuous discharge8
  • Cost for 2: €14.40 (~€7.20 each) — within €15 budget
  • Actual draw: 7A ÷ 3Ah = 2.3C — only 23% of rated 30A capacity
  • Running at 23% rated discharge is gentle on the cell, promotes longevity
  • Only product found on Amazon.fr with explicitly stated discharge rate (searches: «pile 18650 rechargeable flat top», «18650 haute décharge plat», «18650 flat top 20A» — all others were chargers, packs with connectors, or NiMH cells)9
  • Verdict: ✅ RECOMMENDED — within budget, verified specs, favorable for longevity
  • Capacity sufficient for 15-30 min compressor runtime per charge10

Samsung INR18650-25R 2500mAh 20A — nkon.nl only11

  • Specifications: 2500mAh, 20A discharge, 3.6V, flat top12
  • Cost for 2: €3.90 (€1.95/cell at nkon.nl)
  • Discharge: 20A ÷ 2.5Ah = 8C — 2.3× margin over 3.5C minimum
  • ⚠️ Not found on Amazon.fr
  • Verdict: ✅ Suitable — reputable brand, verified specs, well within budget

DMEGC INR18650-25P 2500mAh 20A — nkon.nl only13

  • Specifications: 2500mAh, 20A discharge, 3.6V, flat top14
  • Cost for 2: €3.30 (€1.65/cell at nkon.nl) — cheapest option with verified specs
  • Discharge: 20A ÷ 2.5Ah = 8C — 2.3× margin over 3.5C minimum
  • ⚠️ Not found on Amazon.fr
  • Verdict: ✅ Suitable — less known brand but specs verified on product page

LG INR18650-HJ2 3000mAh 20A — nkon.nl only15

  • Specifications: 3000mAh, 20A discharge, 3.6V, flat top16
  • Cost for 2: €6.98 (€3.49/cell at nkon.nl)
  • Discharge: 20A ÷ 3Ah = 6.67C — well above 3.5C minimum
  • 20% more capacity than 2500mAh cells → longer runtime per charge
  • 3000mAh is the practical ceiling for 18650 cells meeting the discharge requirement17
  • ⚠️ Not found on Amazon.fr
  • Verdict: ✅ BEST LONGEVITY — most capacity available while meeting discharge spec

JESSPOW 3300mAh (€25.80/4) — Amazon.fr18

  • Discharge: “high” but unspecified ⚠️
  • Cost for 2: €13
  • Verdict: ⚠️ Risky — no confirmed discharge rate for high-drain device19

9V alkaline (PP3 / 6LR61) — rejected

  • Nominal voltage: 9V — ~22% above the device’s 7.4V nominal, risk of damaging motor driver / electronics20
  • Capacity: ~550 mAh per cell21 — 4× below the 2000 mAh minimum
  • Practical continuous current: ~30 mA for any sensible lifespan22 — the compressor draws 7000 mA (~230× more)
  • Form factor: rectangular 17.5 × 26.5 × 48.5 mm23 — physically incompatible with the cylindrical 18650 holders (18 × 65 mm)
  • Verdict: ❌ Inadequate on every axis (voltage, capacity, current delivery, form factor)

9V Li-ion rechargeable (EBL 5400mWh and similar) — rejected

  • Actual capacity: ~600 mAh (5400 mWh ÷ 9V)24 — the mWh label obscures a sub-alkaline mAh figure
  • Intended applications per manufacturer: “smoke alarms, microphones, toys, and medical devices”25 — all low-drain (mA-range) devices
  • Max discharge current not published; onboard protection circuit advertises over-current / short-circuit cutoff26 — will trip well below the 7A the compressor demands
  • Same 9V vs 7.4V voltage mismatch20 and same PP3 form factor incompatibility23 as the alkaline variant
  • Verdict: ❌ Designed for sub-1A low-drain devices, not for a 50W / 7A compressor

Decision

JESSPOW 3000mAh 30A (€14.40 for 2, Amazon.fr). After open search on Amazon.fr across multiple queries9, this is the only bare 18650 flat-top cell with an explicitly stated discharge rate. All other listings are either chargers, battery packs with connectors, or generic cells without discharge specs. Despite the 30A rating, the ATJ 8466 draws only 7A (2.3C on a 3Ah cell) — 23% of rated capacity — which is gentle on the cell and favorable for longevity.

Soldering

  1. Battery capacity: 2 2000mAh lithium batteries Working voltage: DC 7.4V Working current: less than or equal to 7A

    Source: ATJ 8466 Portable Car Tire Air Pump - Lydarz.com (accessed 2026-04-22) Direct specifications for the user’s compressor model battery and operating parameters. ↩︎ ↩︎ ↩︎ ↩︎

  2. I = Cr * Er (Current = C-Rate × Rated Energy in Ah)

    Source: What is a Battery C-Rate? - Power-Sonic Defines the mathematical relationship used to calculate available current from battery C-rate specifications. ↩︎ ↩︎

  3. Product power: 50W

    Source: ATJ 8466 Portable Car Tire Air Pump - Lydarz.com Establishes the power consumption rating for the user’s specific compressor model. ↩︎

  4. This 3.7V 5200mAh rechargeable lithium battery is composed of 2 balanced cells of 2600mAh for a total of 5200mA. The cells are connected in parallel and spot soldered to a protection circuit that provides protection against overvoltage, undervoltage, and over-current.

    Source: XINLANTECH 5200mAh 1s2p — Amazon.fr (accessed 2026-04-22) ↩︎

  5. With parallel cells, capacity in Ah and runtime increases while the voltage stays the same.

    Source: Battery University — BU-302: Series and Parallel Battery Configurations

    1S2P = 1 cell in Series, 2 cells in Parallel. Result: maintains 3.7V but doubles capacity. Two 2600mAh cells in parallel = 5200mAh total at 3.7V. ↩︎

  6. 3.7V 5200mAh 18650 1s2p Rechargeable Lithium-Ion Battery with JST PH2.0/2P Connectors for Bluetooth Speaker, Solar Lamp, Flashlight and More

    Source: XINLANTECH — Amazon.fr product title (accessed 2026-04-22) Product title confirms 1s2p configuration (2600mAh per cell). Marketed for Bluetooth speakers and flashlights — low-drain devices. No discharge rate stated. Calculation: 2.6Ah × 5C = 13A max if rated 5C. ↩︎

  7. Piles Rechargeables 3.7V, 3000mAHh, 30A Batterie à Dessus Plat Haute Capacité pour Lampes de Poche, Lampe Fronta，Lumières de Jardin extérieures (Lot De 4, 18 X 65mm)

    Source: JESSPOW — Amazon.fr product title (accessed 2026-04-22) ↩︎

  8. Overcharging and Discharging Exceeding the recommended charging limits or discharging rates stresses the battery.

    Source: EcoFlow US Blog - Understanding Thermal Runaway in Lithium-Ion Batteries

    JESSPOW specs: 30A discharge on 3000mAh = 10C rating. Safe margin for 15A load: 15A ÷ 30A = 50% utilization (excess capacity for safety). ↩︎

  9. Grande capacité et fort ampérage : Avec une capacité de 3 000 mAh, cette batterie rechargeable de 3,7 V offre une longue durée de vie. De plus, son taux de décharge de 30 A garantit une alimentation constante.

    Source: JESSPOW — Amazon.fr product page (accessed 2026-04-22) ↩︎ ↩︎

  10. Typically, manufacturers rate capacity at the 1C rate, meaning a 10Ah battery can deliver 10 amps for one hour. In contrast, at 0.5C, it provides 5 amps for two hours, and at 2C, it delivers 20 amps for 30 minutes.

    Source: What is a Battery C-Rate? - Power-Sonic

    For JESSPOW 3000mAh: At 10A avg draw ≈ 18 min; at 5A draw ≈ 36 min. Actual runtime affected by compressor efficiency and pressure tank discharge curve. ↩︎

  11. Samsung INR18650-25R 2500mAh - 20A - Productiejaar 2020-2021

    Source: nkon.nl product page title (accessed 2026-04-22) ↩︎

  12. Capaciteit: 2500mAh Nominale Spanning: 3,6V - 3,7V Ontlaadstroom: 20A Pluspool: Flat top

    Source: nkon.nl — Samsung INR18650-25R 2500mAh - 20A product page (accessed 2026-04-22) ↩︎

  13. DMEGC INR18650-25P 2500mAh - 20A

    Source: nkon.nl product page title (accessed 2026-04-22) ↩︎

  14. Capaciteit: 2500mAh Nominale Spanning 3,6V - 3,7V max. Ontlaadstroom: 20A Pluspool: Flat top

    Source: nkon.nl — DMEGC INR18650-25P 2500mAh - 20A product page (accessed 2026-04-22) ↩︎

  15. #+BEGIN_QUOTE ↩︎

  16. Capaciteit: 3000mAh Nominale Spanning 3,6V - 3,7V max. Ontlaadstroom: 20A Pluspool: Flat top

    Source: nkon.nl — INR18650-HJ2 3000mAh - 20A product page (accessed 2026-04-22) ↩︎

  17. Capaciteit: 3500mAh max. Ontlaadstroom: 10A

    Source: nkon.nl — LG INR18650-MJ1 product page (accessed 2026-04-22) 10A ÷ 3.5Ah = 2.86C — below the 3.5C minimum required. Beyond 3000mAh, 18650 cells trade discharge rate for capacity, making them unsuitable here. 5000mAh claims in 18650 format are physically implausible given the cell dimensions (18mm × 65mm). ↩︎

  18. 3.7 Volt Rechargeable Batteries, 4 x 3300 mAh High Capacity Batteries for LED Headlamp, Remote Control Car (Flat Top, 18 x 65 mm)

    Source: JESSPOW 3300mAh — Amazon.fr product title (accessed 2026-04-22) Product description mentions “high discharge rate” but omits any amperage figure. Without a stated discharge rate, suitability for a 7A compressor cannot be verified. ↩︎

  19. Generally, lithium-ion batteries become vulnerable to thermal runaway at temperatures above 80°C (176°F).

    Source: EcoFlow US Blog - Understanding Thermal Runaway in Lithium-Ion Batteries

    Additional spec: “The critical thresholds for a violent thermal runaway reaction were determined to be a maximum cell case temperature above 250°C and the release of over 0.5 L of vent gas.” Source: FAA Fire Safety Report

    Risk for your compressor: Using 5C battery (13A rated) at 15A continuous = internal temp > 250°C risk. ↩︎

  20. The ATJ 8466 operates at DC 7.4V nominal (see Context and 1). A 9V source sits ~22% above that operating point. Li-ion motor drivers and BLDC controllers are typically specified against a cell-pack voltage window; applying a chemistry with a different voltage profile (9V primary ≈ 9.2V fresh, 9V Li-ion ≈ 8.4V charged) falls outside the design envelope and risks damaging the controller or motor. ↩︎ ↩︎

  21. Alkaline (IEC 6LR61) “550” milliamp-hours represents the typical capacity

    Source: Wikipedia — Nine-volt battery (accessed 2026-04-24) 550 mAh is 3.6× below the 2000 mAh originally fitted in the ATJ 8466 (see 1). ↩︎

  22. the alkaline version has a capacity of around 600mAH. So for any sensible lifespan you are looking at a useful maximum of around 30mA

    Small 9 volt batteries are designed to power smoke alarms for a couple of years but won’t supply 150ma for even a day.

    Source: Arduino Forum — What is the max current I could draw from a 9V battery? (accessed 2026-04-24) Corroborating datapoint from the same thread: “at 50 mA it looks like you are down to 7V in 5-10 hours” — i.e. voltage collapses well before nominal capacity is delivered under even moderate load. The compressor’s 7 A draw is ~230× the 30 mA practical ceiling. ↩︎

  23. The standard PP3 nine-volt battery measures 17.5 mm (depth) × 26.5 mm (width) × 48.5 mm (height)

    Source: Wikipedia — Nine-volt battery (accessed 2026-04-24) Rectangular with both terminals on the same top face via snap connectors. The ATJ 8466 houses cylindrical 18650 cells (18 × 65 mm, axial terminals); the PP3 form factor cannot physically sit in the battery holder. ↩︎ ↩︎

  24. Lithium-ion versions offer approximately 620 mAh, while lithium polymer variants provide around 520 mAh capacity.

    Source: Wikipedia — Nine-volt battery (accessed 2026-04-24) The “5400 mWh” figure on the EBL listing converts to 5400 ÷ 9 = 600 mAh, consistent with the Wikipedia figure. Labelling in mWh rather than mAh makes the capacity appear ~9× larger at a glance while the actual charge capacity remains sub-alkaline-grade for a compressor. ↩︎

  25. ideal for smoke alarms, microphones, toys, and medical devices

    Source: EBL Official — Rechargeable 9V Lithium Batteries 5400mWh product page (accessed 2026-04-24) All listed applications are low-drain (smoke detectors: µA to low mA; wireless microphones: tens of mA; medical devices of this class: low mA). None remotely approaches 7 A. ↩︎

  26. over-charge, over-discharge, short circuit [protection]

    Source: EBL Official — Rechargeable 9V Lithium Batteries 5400mWh product page (accessed 2026-04-24) No maximum continuous discharge current is published. These 9V Li-ion packs are built as two small Li-ion cells in series with a step-up/regulator board and a protection IC sized for their advertised use case (smoke alarms, low-drain devices) — a 7 A sustained load will trip the protection (best case) or damage the internal regulator (worst case). ↩︎