LG HE4 18650 2500mAh 20A Battery (10-Pack) — Genuine Flat Top Cells for Flashlights & Power Tools

Overview

The LG HE4 is a 2,500mAh, 20A continuous-discharge 18650 cell from LG Chem, first released in late 2013. It's one of the longer-standing high-drain 18650 cells still in regular use, commonly paired with LG's slightly earlier HE2 as one of the two "standard" high-current 18650 references in the  flashlight, and DIY battery pack communities. Its main appeal is consistency — the cell performs close to its rated numbers, holds up under repeated high-drain cycling, and has over a decade of documented use behind it.

Quick Specs

A note on that voltage figure: you'll sometimes see the HE4 listed as "3.7V nominal." That's a rounded, generic Li-ion convention, not the number on LG's actual spec sheet — the documented nominal voltage is 3.6V. It's a small distinction, but it matters if you're doing pack voltage calculations.

What You're Actually Getting

This is a flat top, unprotected cell — meaning there's no built-in circuit enforcing the voltage and current limits above. Any device or battery pack you put it in needs its own protection (a BMS, or a device with integrated cell protection) to actually manage overcharge, over-discharge, and short-circuit protection. That's standard for this class of high-drain 18650, not a shortcoming specific to the HE4.

Where the HE4 Performs Well

• High-output flashlights and headlamps — steady discharge under sustained turbo or high modes, not just short bursts
• Sub-ohm regulated devices — comfortable current headroom for most 60-100W+ builds
• Power tools — cordless drills, saws, and similar tools that draw hard and repeatedly
• E-bike and scooter packs — commonly used in parallel-cell configurations needing sustained current delivery
• General DIY battery packs — predictable performance and a wide operating temperature range make it a forgiving cell to design around

Not the right fit if your device needs sustained current above 20A per cell, or if capacity matters more to you than discharge rate.

LG HE4 vs. 3 Comparable Cells

The HE4 and 25R are close enough in spec that either works for most 20A-class builds — the choice often comes down to price and availability. If you need more capacity and can accept a lower discharge ceiling, the 30Q is the better fit.

How to Verify You've Received a Genuine Cell

• Weight — a genuine HE4 weighs 45-47g. Noticeably lighter can indicate a smaller cell rewrapped in HE4 packaging.
• Printed markings — authentic cells carry consistent laser-etched or printed date/lot codes matching LG's documentation format, not a generic sticker.
• Discharge rating claims — if a listing advertises the HE4 at 30A or 35A continuous without qualifying it as a pulse figure, that's not supported by LG's datasheet and is worth treating with caution.
• Seller transparency — sellers who reference LG's actual datasheet rather than a generic spec list are a better sign than ones who don't.

Real-World Test Data

Independent capacity testing on the HE4 — discharging at 2.5A down to the 2.5V cutoff — has measured actual capacity at approximately 2,493mAh, closely matching the 2,500mAh nominal rating.

• Discharge curve: holds a steady voltage plateau through most of the discharge cycle, tapering only in the final stretch before the 2.5V cutoff — not an early or sudden drop-off.
• Heat under load: in side-by-side bench testing against the HE2 at matched discharge rates, the HE4 ran a few degrees cooler on average (roughly 34-35°C surface temperature vs. 36-37°C for the HE2 under the same conditions).
• Storage behavior: LG's documentation specifies tighter storage temperature windows the longer a cell sits unused — roughly -20°C to 60°C for up to a month, narrowing to -20°C to 45°C for three months, and -20°C to 20°C for a full year. Store at around 40% charge if the cells won't be used for an extended period.

Frequently Asked Questions

Q: What is the actual continuous discharge rating of the LG HE4?
A: According to LG's official datasheet, the maximum continuous discharge current (CDR) is 20A. The pulse discharge can reach up to 25A (short pulses, typically 5-10 seconds). Please distinguish between continuous and pulse ratings.

Q: What is the difference between HE4, HE2, and HG2?
A: HE4: 2500mAh / 20A CDR; HE2: 2500mAh / 20A CDR (HE4 has lower internal resistance and slightly better pulse capability); HG2: 3000mAh / 20A CDR. The HE4 offers excellent value for users seeking stable performance.

Q: Can I use this battery in a standard flashlight?
A: Not recommended. Standard flashlights (<500 lumens) draw only 0.5A-2A. Using a 20A HE4 is overkill and cost-inefficient. For standard lights, consider 2600mAh or 3500mAh cells.

Q: Does this battery have a protection circuit?
A: No. This is a bare, unprotected cell. Use with devices/chargers that have built-in over-charge and over-discharge protection.

Q: What are the benefits of the 10-pack?
A: The 10-pack is ideal for bulk purchases, multi-cell devices (e.g., dual/quad battery ), DIY battery pack builds, and as a spare cell inventory.

Q: How long does the HE4 actually last?

A:LG rates it for 200 cycles before capacity drops below roughly 2,000mAh (an 80% retention cutoff). The cell keeps working past that point, but with reduced runtime. Lighter, more moderate discharge use extends usable life well beyond that mark.

Q: What's the self-discharge rate?

A:No unusually high self-discharge figure is published for this cell — expect standard low single-digit percentage loss per month under normal storage. A cell losing charge noticeably faster than that while idle is more likely counterfeit or degraded than a chemistry issue.

Q: Is the HE4 compatible with my device?

A:If your device is built around standard 18650 cells and doesn't draw more than 20A continuous per cell, and your charger handles standard Li-ion charging (4.2V max, up to 4A), the HE4 will work.

Q: Can I mix HE4 cells with other models in a pack?

A:Not recommended. Mixing cells of different capacities, ages, or internal resistance in a series or parallel pack causes imbalanced charge/discharge behavior, which shortens pack life and creates a safety risk. Use matched HE4 cells from the same batch where possible.