Description
▌PRODUCT DESCRIPTION
>> MORE HOURS ON THE DECK. FEWER TRIPS TO THE CHARGER. <<
Your uConsole is open, the terminal is scrolling, and the battery icon is already going amber. Half the cells on the market promise 3500mAh and deliver a story. You need the cell that actually holds the line.
The LG MJ1 is one of the highest capacity 18650 cells ever put into production: 3500mAh typical, 3400mAh minimum, 10A max continuous discharge. Genuine LG Energy Solution INR18650MJ1 cells, brand new, Grade A. Not rewraps. Not pulls. Not a mystery cell with an optimistic label.
Capacity and current in the same can is the hard part. The MJ1 does both. High enough capacity to run a handheld terminal through a long night, and enough current headroom to handle the bursts when the WiFi radio, the display, and the CPU all want power at once.
Flat top, unprotected, built for integration. The flat positive terminal is made for spot-welded pack builds and for devices with dedicated battery holders and onboard protection circuitry. This is a bare cell for builders who know what a BMS is and why they need one.
Key Specs:
- Model: LG INR18650MJ1
- Chemistry: Li-Ion, INR (nickel manganese cobalt)
- Typical Capacity: 3500mAh
- Minimum Capacity: 3400mAh
- Nominal Voltage: 3.635V
- Max Charge Voltage: 4.20V (CC/CV)
- Standard Charge Current: 0.5C (1.7A)
- Max Charge Current: 1C (3.4A)
- Max Discharge Current: 10A
- Discharge Cutoff: 2.5V
- Cycle Life: 400 cycles to 80% or more of minimum capacity
- Protection: None (unprotected cell)
- Terminal: Flat top
- Wrap Color: Green
- Charge Temperature: 0 to 45°C (32 to 113°F)
- Discharge Temperature: -20 to 60°C (-4 to 140°F)
- Dimensions: 18.4 x 65.0 mm nominal, 18.5 x 65.2 mm max (0.72 x 2.56 in nominal)
- Weight: approx. 47g, 49g max (1.7 oz)
- Safety Testing: UN38.3 tested; safety tested per UL1642 test methods
- Shipping State: approx. 30% charge
- Country of Origin: South Korea
Applications that matter:
ClockworkPi uConsole & DevTerm. The MJ1 is a favorite upgrade for handheld Linux terminals that run on 18650 cells with onboard battery management. More capacity means more time in the shell and less time hunting for an outlet.
Flipper Zero Add-On Boards. Compatible 18650-powered Flipper Zero boards and backpacks get a cell with the capacity to run long sessions and the current to handle radio bursts without sagging.
Custom Battery Packs. Flat top terminals are built for spot welding. Pair the MJ1 with a proper BMS and build packs for portable rigs, field kits, and power banks.
Embedded & Field Builds. Any project with a dedicated 18650 holder and real protection circuitry: dataloggers, portable SDR rigs, sensor nodes, and long-haul field gear.
3500mAh. 10A. The cell that holds the line.
▌README.TXT – INSTRUCTIONS FOR USE
Documentation:
Compatibility: The LG MJ1 is an unprotected, flat top 18650 Li-Ion cell. It is intended for spot-welded battery packs with a BMS, or for devices with a dedicated 18650 holder and built-in battery protection circuitry. It is not a protected consumer battery and is not intended for use as a loose, stand-alone power source.
Step 1: Inspect Check the cell before every use. The wrap and the insulator ring around the positive terminal must be intact, with no tears, nicks, or exposed metal. Do not use a cell with a damaged wrap, dents, or signs of leakage.
Step 2: Confirm Your Device Make sure your device is designed for unprotected flat top 18650 cells and has its own protection circuitry. Some spring holders are built for button top cells and may not make reliable contact with a flat top.
Step 3: Install Observe polarity markings in the holder. The flat end with the insulator ring is positive (+). Install multi-cell devices with cells of the same model, age, and charge level.
Step 4: Charge The cell ships at approximately 30% charge, so charge it fully before first use. Use a smart charger designed for Li-Ion cells (CC/CV, 4.20V). Standard charge is 1.7A; do not exceed 3.4A. Charge on a fire-proof surface and never leave charging cells unattended.
Step 5: Operate Stay at or under the 10A maximum discharge current and stop at 2.5V. Under heavy loads the cell will get warm. Let it cool before recharging.
Step 6: Store & Transport Never carry loose cells in a pocket, bag, or purse. Keep each cell in a plastic battery case. Store cells separately, out of direct sunlight, in a cool, dry place. For storage up to a year, LG specifies -20 to 20°C (-4 to 68°F).
PRO TIP: If your device or pack runs on two or more cells, buy them together and keep them together. Charge, use, and replace them as a matched set, and never mix cells of different ages, lots, or makers. Mixing a fresh cell with a tired one is how packs drift out of balance and how cells get over-discharged.
▌DEBUG LOG – TROUBLESHOOTING
ISSUE: Device won’t power on with the cell installed. FIX: Check polarity first. Then check contact: flat top cells can sit short of the contact in holders designed for button tops. Confirm the cell is charged, since it ships at about 30%.
ISSUE: Charger won’t recognize the cell or shows an error. FIX: Reseat the cell and clean the contacts. If the cell has been deeply discharged well below 2.5V, do not try to force a recovery charge. Recycle it.
ISSUE: Runtime is shorter than expected. FIX: Rated capacity is measured at a low 680mA discharge. High current draw, cold temperatures, and a higher cutoff voltage in your device all reduce usable capacity. Cold hits hard: LG rates the MJ1 at about 80% capacity at 0°C and 70% at -10°C. Capacity also fades with use, to about 80% after 400 cycles.
ISSUE: Cell gets hot during use. FIX: The MJ1 runs warm near its 10A limit. Reduce the load, improve airflow, and let the cell cool before charging. If your device pulls more than 10A continuous, this is the wrong cell for it.
ISSUE: Multi-cell device shuts off early or the cells read different voltages. FIX: The cells are mismatched in age, capacity, or charge. Fully charge each cell individually on a smart charger, then reinstall them as a matched set. Replace them as a set going forward.
ISSUE: Wrap is torn, nicked, or peeling. FIX: Stop using the cell. A damaged wrap can short against metal holders and contacts. Have it rewrapped by someone experienced, or recycle it.
▌SYS.WARN – WARNINGS, HAZARDS & DISCLAIMERS
Lithium-Ion Hazard. Lithium-ion cells may explode, burn, or cause a fire if misused or mishandled. Misusing or mishandling lithium-ion cells can cause serious personal injury, property damage, or death. The user must understand how to safely handle lithium-ion cells before purchase.
Unprotected Cell. This cell has no built-in protection circuit. Only use it in a protected battery pack or in a device with proper battery protection circuitry. Do not overcharge or over-discharge. Only use within the manufacturer’s listed specifications.
Not for Vaping Devices. Do not use with e-cigarettes, vaporizers, or similar devices.
Short Circuit. Do not short circuit. Keep cells away from metal objects such as keys, coins, and tools. Never store a loose cell in a pocket, purse, or bag. Always use a protective battery case.
Physical Damage. Do not use if the wrapper or insulator is damaged or torn, or if the cell is damaged in any way. Do not modify, disassemble, puncture, cut, crush, or incinerate. Do not expose to liquids or high temperatures.
Assembly. Do not solder directly to the cell. Spot weld only.
Charging. Charge only with a smart charger designed for this type of lithium-ion cell. Always charge in or on a fire-proof surface and never leave charging cells unattended. Do not mix old and new, or used and unused, cells.
Compatibility. No express or implied guarantee of compatibility with any device is made. Confirm your device’s requirements before use.
Transport Certification. This cell is UN38.3 tested and safety tested per UL1642 test methods, and is shipped at approximately 30% state of charge in line with IATA and US DOT lithium battery shipping regulations. The UN38.3 test report, datasheet, and Product Safety Data Sheet are available for download on this page, and certification is available upon request to authorities, carriers, and other parties with a legitimate need.
Shipping Restrictions. Lithium-ion cells sold without equipment are regulated as hazardous materials. This item ships only to addresses in the 48 contiguous United States, by ground service. It cannot be shipped internationally, by air, or to Alaska, Hawaii, or US territories.
Not a Toy. Keep out of reach of children and pets.
Disposal. Do not dispose of in household trash or fire. Recycle at a battery collection or drop-off point in accordance with local regulations.
Resellers. Resellers must forward all warnings to all customers for their reference and safety.
Disclaimer. This product is sold “as-is” for use by qualified individuals experienced with lithium-ion cells. Use is at your own risk. The buyer is responsible for any damage or injury caused by misuse or mishandling of lithium-ion cells and chargers. Rabbit-Labs LLC makes no warranty, express or implied, regarding fitness for a particular purpose. Maximum liability shall not exceed the purchase price of the product.
© Rabbit-Labs LLC. All rights reserved. The Rabbit-Labs name and logo are trademarks of Rabbit-Labs LLC. LG and MJ1 are trademarks of their respective owners.
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