Battery Building ToolsCell Database UR18650FJ

✱ Render

18.1 × 64.8 mm · 46.5 g

18650NMC

Sanyo UR18650FJ

Name: Sanyo UR18650FJ Lithium Battery Cell
Brand: Sanyo

Sanyo

Capacity2100 mAh7.77 Wh · 167.1 Wh/kg

Rated continuous4.2 A4.2A

Voltage window3.7 V2.5 – 4.2 V

Standard charge2100 mA~1 h to full

Build a pack with this cell →Download spec sheet (PDF)

At 2100 mAh, this ranks #123 of 169 18650 cells in our database. On the lower end for capacity among 18650 cells. A mid-range 18650 cell. Solid for builds that don't need extreme capacity or discharge.

Full specifications

Electrical
Chemistry	NMC
Nominal voltage	3.7 V
Max charge voltage	4.2 V
Discharge cutoff	2.5 V
Max continuous discharge	4.2A
Standard charge current	2100 mA
Standard discharge current	420mA
Physical
Form factor	18650
Dimensions	18.1mm × 64.8mm
Weight	46.5 g
Top type	Flat Top
Protected	No
Wrap color	Red
Insulator ring	Orange
Performance
Capacity	2100 mAh
Energy	7.77 Wh
Specific energy	167.1 Wh/kg
Energy density	466.01 Wh/L
Power density (gravimetric)	334 W/kg
Power density (volumetric)	932 W/L
Operating Limits
Charge temp	0°C to 40°C
Discharge temp	-20°C to 60°C

At the standard 2100 mA charge rate, a full charge takes about 1 hours. The last bit is a slow taper to top it off.

Voltage operating window

Cutoff
2.5VNominal
3.7VMax charge
4.2V

Usable range: 1.7V

C-rate conversion: Sanyo UR18650FJ (2100mAh)

C-Rate	Current (A)	Theoretical runtime
0.2C	0.42 A	5h 00m
0.5C	1.05 A	2h 00m
1C	2.1 A	1h 00m
2C	4.2 A	30m

Highlighted row is closest to the rated 4.2A continuous discharge.

Charging

Rate	Current	Estimated time
0.5C	1,050 mA	~2h 00m
1C	2,100 mA	~1h 00m

These are estimates for the constant-current phase. Real charge time is a bit longer because of the slow taper at the end.

Pack scaling

Series voltage configurations

Config	Nominal V	Max V	Min V	Common use
1S	3.7V	4.2V	2.5V	Flashlights, single-cell devices
2S	7.4V	8.4V	5V	RC vehicles, 7.2V packs
3S	11.1V	12.6V	7.5V	Power tools (10.8V nominal)
4S	14.8V	16.8V	10V	Ebike (small), some power tools
7S	25.9V	29.4V	17.5V	Ebike (24V system)
10S	37V	42V	25V	Ebike (36V system)
13S	48.1V	54.6V	32.5V	Ebike (48V standard)
14S	51.8V	58.8V	35V	Ebike (52V high-power)
16S	59.2V	67.2V	40V	DIY powerwall

Parallel capacity scaling

Config	Capacity	Energy	Max discharge
1P	2,100 mAh	7.8 Wh	4.2 A
2P	4,200 mAh	15.5 Wh	8.4 A
3P	6,300 mAh	23.3 Wh	12.6 A
4P	8,400 mAh	31.1 Wh	16.8 A
5P	10,500 mAh	38.8 Wh	21 A
6P	12,600 mAh	46.6 Wh	25.2 A

Example pack configurations

7S2P

24V ebike / small pack

14 cells25.9V nominal4,200mAh109Wh8A maxCell weight: 0.65 kg (add ~15% for wiring and BMS)

13S4P

48V ebike standard

52 cells48.1V nominal8,400mAh404Wh17A maxCell weight: 2.42 kg (add ~15% for wiring and BMS)

16S4P

DIY powerwall

64 cells59.2V nominal8,400mAh497Wh17A maxCell weight: 2.98 kg (add ~15% for wiring and BMS)

4S6P

Power tool replacement

24 cells14.8V nominal12,600mAh186Wh25A maxCell weight: 1.12 kg (add ~15% for wiring and BMS)

Design a custom pack with this cell:

Pack Planner →Pack Designer →

Application suitability

PowerwallsUsable for powerwalls but lower capacity means you'll need more cells to hit your target kWh.

Ebike PacksNot enough discharge for ebike use. Voltage sag would be a problem under load.

Car AudioNot enough discharge for car audio amplifiers. You need at least 15-20A continuous for most setups.

High-Drain VapingBelow the 25A Mooch CDR threshold that high-drain vaping needs. Use a higher-drain cell.

FlashlightsLower capacity means shorter runtime. Better cells are available for flashlight use.

Power ToolsNot enough discharge or capacity for power tool use.

Physical dimensions

Dimensions18.1mm × 64.8mm

TopFlat Top

Format18650

Similar cells

Same format and chemistry, within ±500mAh capacity:

Cell	mAh	CDR	Wh	Weight	Wh/kg
Sanyo UR18650FJ (this cell)	2100	4.2A	7.77	46.5g	167.1
LG LGDB118650	2600	—	9.8	—	—
LG LGDBB11865	2600	—	9.8	—	—
BAK C18650CC	2600	2A	9.6	—	—
Cham CMICR18650F	2600	—	9.6	45.5g	211
GP Batteries ICR18650-26F	2600	5A	9.6	—	—

Build with this cell

Pack PlannerSize your pack. Voltage, capacity, runtime, BMS.Pack Designer2D & 3D layout for your exact cell arrangement Pack BuilderBalance cells by capacity and internal resistance

Frequently asked questions

What is the capacity of the Sanyo UR18650FJ?

What is the maximum discharge rate of the Sanyo UR18650FJ?

How many UR18650FJ cells do I need for a 48V ebike battery?

What does the Sanyo UR18650FJ weigh?

Can I use the UR18650FJ for vaping?

What temperature range can the UR18650FJ operate in?

What size is the Sanyo UR18650FJ?

Handling and safety

Lithium cells can be dangerous if mishandled. A few things to keep in mind:

Never charge above 4.2V or discharge below 2.5V.
Store cells at around 3.6-3.8V (roughly 40-60% charge) for long-term storage.
Don't mix cells with different capacities, chemistries, or states of charge in a pack.
Inspect wraps before use. A torn wrap can cause a short circuit.
Always use a BMS or balance charger appropriate for your pack configuration.
Keep cells away from metal objects, keys, and coins. A short across the terminals can cause fire.

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Specs come from manufacturer datasheets and independent testing; Mooch-tested discharge ratings are shown when available because they reflect real continuous performance better than headline datasheet numbers. Browse the full 18650 & 21700 cell database to compare every cell.

Disclaimer: We do our best to keep the information on this page accurate, but we cannot guarantee that all specifications are correct or up to date. Cell characteristics can vary between production batches and may change over time. Do not rely solely on this data for safety-critical applications. Always verify against the manufacturer's official datasheet before use.