Battery Building ToolsCell Database 25EF

✱ Render

18.45 × 65.2 mm

18650NMC Mooch-tested · 20 A

Efest 25EF

Name: Efest 25EF Lithium Battery Cell
Brand: Efest

Efest

Capacity2500 mAh9 Wh

Mooch continuous20 ASize to this figure

Voltage window3.6 V2.5 – 4.2 V

Build a pack with this cell →Download spec sheet (PDF)Mooch's test ↗

At 2500 mAh, this ranks #132 of 279 18650 cells in our database. Mid-range for capacity among 18650 cells. Higher discharge than 77% of 18650 cells in our database. Great for high-drain builds.

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Full specifications

Electrical
Chemistry	NMC
Nominal voltage	3.6 V
Max charge voltage	4.2 V
Discharge cutoff	2.5 V
Max continuous discharge	20A (Mooch-tested)
Mooch CDR (trusted)	20 A
Physical
Form factor	18650
Dimensions	18.45mm × 65.2mm
Top type	Flat Top
Protected	No
Wrap color	Green
Performance
Capacity	2500 mAh
Energy	9 Wh
Energy density	516.31 Wh/L
Power density (volumetric)	4,130 W/L

Independent test data: Mooch's test of the 25EF ↗

Voltage operating window

Cutoff
2.5VNominal
3.6VMax charge
4.2V

Usable range: 1.7V

C-rate conversion: Efest 25EF (2500mAh)

C-Rate	Current (A)	Theoretical runtime
0.2C	0.5 A	5h 00m
0.5C	1.25 A	2h 00m
1C	2.5 A	1h 00m
2C	5 A	30m
3C	7.5 A	20m
5C	12.5 A	12m
8C	20 A	7m 30s

Highlighted row is closest to the rated 20A continuous discharge.

Charging

Rate	Current	Estimated time
0.5C	1,250 mA	~2h 00m
1C	2,500 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	3.6V	4.2V	2.5V	Flashlights, single-cell devices
2S	7.2V	8.4V	5V	RC vehicles, 7.2V packs
3S	10.8V	12.6V	7.5V	Power tools (10.8V nominal)
4S	14.4V	16.8V	10V	Ebike (small), some power tools
7S	25.2V	29.4V	17.5V	Ebike (24V system)
10S	36V	42V	25V	Ebike (36V system)
13S	46.8V	54.6V	32.5V	Ebike (48V standard)
14S	50.4V	58.8V	35V	Ebike (52V high-power)
16S	57.6V	67.2V	40V	DIY powerwall

Parallel capacity scaling

Config	Capacity	Energy	Max discharge
1P	2,500 mAh	9 Wh	20 A
2P	5,000 mAh	18 Wh	40 A
3P	7,500 mAh	27 Wh	60 A
4P	10,000 mAh	36 Wh	80 A
5P	12,500 mAh	45 Wh	100 A
6P	15,000 mAh	54 Wh	120 A

Example pack configurations

7S2P

24V ebike / small pack

14 cells25.2V nominal5,000mAh126Wh40A max

13S4P

48V ebike standard

52 cells46.8V nominal10,000mAh468Wh80A max

16S4P

DIY powerwall

64 cells57.6V nominal10,000mAh576Wh80A max

4S6P

Power tool replacement

24 cells14.4V nominal15,000mAh216Wh120A max

Design a custom pack with this cell:

Pack Planner →Pack Designer →

Application suitability

PowerwallsHigh capacity means more stored energy per cell. Fewer cells needed for a given kWh target.

Ebike PacksGood balance of capacity for range and discharge for hills. Works well in most ebike packs.

Car AudioEnough discharge to handle amplifier bursts without voltage sag.

High-Drain VapingUsable in regulated mods at moderate wattage. Not recommended for mechanical mods.

FlashlightsDecent runtime. Works well for most flashlights.

Power ToolsSufficient discharge and capacity for most power tool packs.

Physical dimensions

Dimensions18.45mm × 65.2mm

TopFlat Top

Format18650

Similar cells

Same format and chemistry, within ±500mAh capacity:

Cell	mAh	CDR	Wh	Weight	Wh/kg
Efest 25EF (this cell)	2500	20A	9	—	—
LG LGABD11865	3000	5.8A	11.3	48.5g	232
LG LGDBD11865	3000	5.8A	11.3	48.5g	232
Samsung ICR18650-30B	2950	5.9A	11.2	48g	232
Samsung ICR18650-30A	3000	6A	11.1	48g	231
Ampace JP30P1	3000	36A	10.8	50g	216

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 Efest 25EF?

What is the maximum discharge rate of the Efest 25EF?

How many 25EF cells do I need for a 48V ebike battery?

Can I use the 25EF for vaping?

What size is the Efest 25EF?

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.