18650 Battery Charger 4 Bay Smart Universal Charger for 3.7V
Quick take
This 4-bay USB charger is made for 3.7V lithium-ion rechargeable batteries, including common sizes like 18650, 26650, and 21700. It can charge multiple cells at once and uses per-bay indicators to show status, with built-in charging and discharging management for protection. The main catch is power and compatibility, it is USB-only and some buyers report it may charge slower or only work reliably with certain USB adapter outputs.
Pros and cons
Pros
- Four independent charging bays let you charge 4 lithium-ion cells at the same time.
- Designed for 3.7V lithium-ion batteries (not AA/AAA or NiMH), including 18650, 26650, 21700, and several smaller sizes.
- Status light indicators show charging vs fully charged states.
- Charging and discharging management circuit with multiple protections (helps reduce common failure risks like overcharge or short circuit).
Cons
- USB-only operation, you will need a suitable 5V power source, not a direct wall plug.
- Some users report USB adapter output matters, with slower charging when the adapter is not a close match.
- Some indicator behavior may be unclear (for example, lights staying red can make it harder to confirm fully charged).
What buyers think
Buyer-review evidence focuses on day-to-day charging performance, convenience, and clarity of the indicator lights. Multiple shoppers describe the charger as working well and charging “pretty fast,” especially when charging four batteries at once. Ease of use is a common theme, with buyers liking the setup and the idea of charging different compatible 3.7V lithium-ion cell sizes in separate bays. On the negative side, some buyers report indicator-light behavior that can remain red, and a few point out that USB adapter choice can affect whether charging is slower or not as expected.
How it works and what it charges
This is a 4-bay lithium-ion charger built for 3.7V rechargeable cells. It is compatible with a wide range of common sizes such as 18650, 26650, 21700, and also smaller form factors like 10440, 14500, 16340, 16650, 18500, and others listed for 3.7V lithium-ion use. It is not intended for AA/AAA batteries or NiMH cells.
Each bay runs independently, so you can top up multiple cells during one session. That makes it a practical match for flashlight, headlamp, security camera, and other gear that commonly uses 18650-class batteries.
USB power requirement is the biggest practical consideration
The charger is designed to run from USB power, using a 5V working voltage. That’s convenient for travel and for situations where wall outlets are inconvenient (for example, plugging into a laptop or power bank).
However, buyer feedback suggests that not all USB adapters behave the same. If your USB charger output is not a close match, charging speed may be slower, and in at least one case the user reported needing a specific adapter rating to get the charger to work as expected. If you want consistent results, plan to use a quality 5V USB source and avoid relying on underpowered ports.
Safety features and battery management
The charger includes a charge and discharge management circuit plus multiple protection measures intended to reduce common battery hazards. The protections mentioned include prevention against reverse connection, short circuit, overcharge, over discharge, and over-current damage. In practice, this is what you want to see in a multi-bay charger, because you are increasing the number of cells being handled at once.
Indicator lights: helpful, but watch for ambiguity
The charger uses indicator lights per bay, with red meaning charging and green meaning fully charged. That’s straightforward in theory, and many users appreciate the “status visibility” while they charge.
That said, limited feedback indicates the lights may not always change the way a buyer expects. If a bay’s light stays red even when you think charging is complete, you may want to double-check your USB power source, battery type, and battery condition (for example, very depleted or incompatible cells can affect charging behavior). Buyer-review evidence is limited here, so consider the indicators as a guide rather than an absolute guarantee of state if something looks unusual.
Pros and cons (real-world fit)
Best for
- People who own multiple 3.7V lithium-ion cells and want to charge up to four at once.
- Users charging 18650, 26650, 21700, and similar cells for devices like flashlights or headlamps.
- Travel and portable setups where USB charging is preferable to a bulky wall charger.
Who should avoid it
- If you need a charger for AA/AAA or NiMH batteries, this is not that type.
- If your charging setup depends on a weak or unknown USB adapter, you may see slower charging or less consistent performance.
- If you strongly rely on perfect “red to green” indicator behavior for timing, note that some buyers report confusing light behavior.
Is it worth it?
If your goal is a straightforward 4-bay USB charger for 3.7V lithium-ion batteries, this one makes sense, especially when you want to charge several cells in one session. The safety-focused battery management and compatibility with multiple cell sizes are clear strengths. The main decision point is practical power and indicator confidence, make sure you have a suitable 5V USB source and be prepared for the occasional “indicator does not match expectations” situation reported by a buyer.
FAQ
Will this charge AA or AAA batteries?
No. This charger is for 3.7V lithium-ion rechargeable batteries, not AA/AAA or NiMH cells.
What battery sizes are compatible?
It’s designed for 3.7V lithium-ion cells such as 18650, 26650, 21700, 10440, 14500, 16340, 16650, 18500, and other listed 3.7V lithium-ion formats.
Does it work with wall power?
It uses USB power, so you will need a compatible 5V USB adapter or USB power source. A direct wall outlet connection requires using a USB wall adapter.
Can I charge four batteries at the same time?
Yes, it has four independent charging bays, and it is intended to charge multiple compatible lithium-ion cells simultaneously.
Why would charging be slow with my USB adapter?
Some buyers report charging speed depends on the USB adapter output. Using a suitable 5V USB power source is the best way to keep charging predictable.
What do the light colors mean?
The charger uses indicators where red typically means charging and green means fully charged, per bay.
What safety features does it include?
It includes charge and discharge management and protections intended to help prevent reverse connection, short circuit, overcharge, over discharge, and over-current damage.
Specifications
| Product Title | 18650 Battery Charger 4 Bay Smart Universal Charger for 3.7V Rechargeable Lithium Li ion Batteries Compatible 18650 26650 21700 10400 14500 16340 16650 18500 Battery Charger (Only USB Charger) |
|---|---|
| Category | Electronics > Household Batteries, Chargers & Accessories > Battery Chargers |
| Brand | Tokeyla |
| Manufacturer | Tokeyla |
| Model Number | 819 |
| Color | Black |
| Product Dimensions | 1.4"D x 3.7"W x 5.8"H |
| Output Voltage | 4.2 Volts |
| Input Voltage | 110 Volts (AC) |
| Current Rating | 2 Kiloamps |
| Compatible Devices | 10400, 14500, 16340, 16650, 17670, 18500, 21700, 26650, RCR123a, 𝟣𝟪𝟨𝟧𝟢 |
| Connector Type Used on Cable | USB |
| Number of Ports | 4 |
| Item Dimensions D x W x H | 1.4"D x 3.7"W x 5.8"H |
| Mfr Part Number | 819 |
| UPC | 658392133648 |
| Item Type Name | 𝟣𝟪𝟨𝟧𝟢 Charger Usb |
| Warranty Description | 30 days |
| Unit Count | 1.0 Count |
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