BONAI AA AAA Battery Charger 16 Bay for NiMH NiCD Rechargeable Batteries Independent Control with LED Light and Standard American AC Charging Plug, Battery not Included - Black

What it is and why I tried it

I’ve been gradually swapping disposable AAs and AAAs for rechargeables across remotes, lights, toys, and a rotating cast of gadgets. The pain point wasn’t the batteries—it was the bottleneck. Most chargers top out at four bays and demand matched pairs. The Bonai 16‑bay charger promised independent charging in every slot, the ability to mix AA and AAA, and a simple, brick‑less AC plug. That combination made it an easy candidate for my charging station.

Design and build

The Bonai 16‑bay charger is a wide, low-profile slab with 16 spring-loaded slots arranged in two rows. It’s straightforward: no LCDs, no buttons, just a bank of LEDs—one per slot—and a fixed AC power cord. The chassis is light plastic but doesn’t feel flimsy. The spring contacts have a positive snap and handled both AA and AAA cells without fuss. Filled with 16 AAs, it sits flat and doesn’t tip when you pull cells out, though the lightweight body can slide a bit on slick surfaces. A strip of grippy tape or a mat underneath fixes that.

Two quick notes on physical quirks:
- The power cord is on the short side. If your outlet isn’t close to the surface where you’d like this to live, plan on using a short extension.
- The LEDs are bright. They’re great for visibility across a room, less great if the charger lives in a bedroom.

Setup and usability

There’s nothing to set up. Plug it in and the LEDs flash through a brief self-check; empty bays show solid green, which indicates the slot is powered and ready. Pop in a cell and that bay flips to solid red to indicate active charging. When the cell is full, it goes back to green. If you insert a cell backward or drop in a defective one, you get a flashing red on that bay.

You can drop in any number of cells in any combination of AA and AAA, and you don’t need to pair them. That independence is the big win. In a typical evening I’ll top off a random set—two flashlight AAs, four AAA remotes, three toy batteries—and the charger handles the mix without complication.

Charging performance

Bonai rates each bay at 1.4 V DC with 250–500 mA. In practice, charge current appears to scale with how many bays are occupied; more batteries generally means a slower per‑cell rate. That’s a reasonable trade-off for a high-capacity, simultaneous charger without an external power brick.

My real-world results with common cells:
- 8 AA NiMH (1900–2000 mAh) from nearly empty: ~4.5–5.5 hours
- 16 AA NiMH (same capacity) from nearly empty: just under 10 hours
- 8 AAA NiMH (750–1000 mAh): ~2.5–3.5 hours
- A mixed load (10 AAs + 6 AAAs, all partially discharged): staggered completions between 2 and 7 hours

That stagger is useful. Because each bay is independent, you can pull finished cells as they turn green without disturbing the remaining ones. For bulk workflows—camera flashes, wireless mics, holiday candles—this makes a practical difference. I charged a rotating set of 12 AAs for lights and was able to keep a steady stream of ready cells without waiting for the entire batch to complete.

There’s no readout of voltage, capacity, or internal resistance—this isn’t a diagnostic “smart analyzer.” It’s a volume charger that prioritizes throughput and simplicity. If you want to recondition cells or verify actual mAh, you’ll need a more feature-rich analyzer on the side. For day-to-day charging, the Bonai’s approach is refreshingly uncomplicated.

Thermal behavior and safety

Fully loaded with 16 cells, the chassis gets warm—expected for a passively cooled multi-bay charger—but never approached temperatures that concerned me. The built-in protections (overcharge, overvoltage, overcurrent, overheating, short-circuit, and reverse polarity) behaved as advertised in my tests. A deliberately reversed cell triggered a flashing red and no heat buildup; a “mystery” AAA that’s on its last legs also flagged fault and stayed cool.

Ventilation matters. Don’t bury this under mail or set it on a carpet. On an open shelf or desk, heat was modest. Noise-wise, it’s silent—no coil whine or fan.

LED indicators and day-to-day visibility

I’m a fan of the per‑bay red/green scheme. At a glance from across the room, I can tell which cells are ready. A small quirk: even with no batteries inserted, the LEDs stay green to indicate powered bays. That’s intentional, but it does mean the charger acts like a night light. If that bothers you, park it somewhere out of a bedroom sightline.

Compatibility and what it won’t do

It’s built for NiMH and NiCd cells in AA/AAA formats. It won’t charge alkaline or lithium primary cells, and it’s not a charger for Li‑ion rechargeable AAs (the 1.5 V Li‑ion kind with onboard regulators). Stick to NiMH/NiCd and you’ll be fine.

There’s no USB input—the cord goes directly to mains and supports 110–240 V. I like not having a bulky power brick or wall wart. If you prefer a USB‑powered travel setup, this isn’t that product.

Reliability notes

Across a few weeks of daily use, all bays on my unit have behaved consistently with AA cells. With AAA cells, one slot felt slightly less positive on the spring tension but still held contact and charged. The contacts wipe cleanly; a microfiber cloth and a dab of isopropyl on a cotton swab kept everything pristine after a dusty weekend on location. If you rely on AAA heavily, it’s worth giving each bay a quick test when you unbox the charger, just to learn its feel.

What I like

• True independence per bay: any number, any mix of AA/AAA
• High capacity: 16 slots reduces queueing and keeps devices in rotation
• Clear status: bright, per-slot LEDs with meaningful states (charging, done, fault)
• Brick‑less AC input: simple cable, global 110–240 V compatibility
• Sensible safety features and fault handling
• Quiet and stable thermals with appropriate ventilation

What could be better

• The cord is short; plan for an extension or mount near an outlet
• LEDs are bright and always on for empty bays; a dimmer mode would be welcome
• No analytics (capacity readout, IR, refresh cycle); heavy battery nerds will want a companion analyzer
• Charge rate tapers with more cells loaded; 16‑cell batches are an overnight proposition

Who it’s for

• Households with lots of remotes, toys, flashlights, and smart-home sensors
• Event folks and musicians cycling through piles of AAs/AAAs for mics, recorders, and lights
• Photographers running AA-powered flashes who need bulk charging between sets
• Anyone replacing disposables with NiMH and tired of pairing rules or 4‑bay queues

If you need to test battery health, recover old cells, or micromanage charge currents, look toward a dedicated analyzer for that job. The Bonai is about simple volume charging, and it does that job well.

Tips for best results

• Keep it in a well‑ventilated spot; don’t stack items on top while charging
• Mix and match as needed, but expect longer total time when all 16 bays are filled
• Mark your cells and rotate sets to extend lifespan; don’t leave full cells sitting in the charger for days
• Give the contacts a quick clean every so often to ensure good low-resistance connection

Recommendation

I recommend the Bonai 16‑bay charger for anyone who needs to keep a lot of AA/AAA NiMH cells in circulation with minimal fuss. Its independent bays, high capacity, and straightforward LED feedback fit real-world workflows much better than small paired-slot chargers. The trade-offs—short cord, bright LEDs, and no analytics—are easy to live with given the convenience. If you want a bulk, dependable workhorse that’s simple to use and safe to leave running on a shelf, this charger delivers. Pair it with a separate analyzer if you need deeper battery diagnostics; otherwise, it’s an excellent upgrade that meaningfully reduces battery management overhead.