Powerex MH-C940 Charger-Analyzer for AA/AAA NiMH

The MH-C940 is an 8-slot, independent-channel charger/analyzer for AA and AAA NiMH batteries. It combines flexible charging (soft and fast), per‑slot LCD data, and maintenance modes to keep large battery rotations reliable.

At a glance

• 8 independent bays: mix AA/AAA, capacities, and states of charge—no pairing required.
• Soft and fast charge modes: prioritize longevity or turnaround time.
• Analyzer readouts: slot-by-slot status and mAh delivered to help spot weak cells.
• Maintenance tools: conditioning/refresh can rebalance cells showing reduced runtime.
• Safety-focused control: microprocessor-managed voltage and temperature monitoring with automatic termination.
• Chemistry: NiMH AA/AAA only (not for lithium-ion, alkaline, NiCd, C/D, or 9V).

When to choose the MH-C940

• Use if you manage many AA/AAA cells at once and need independent bays for mixed sets.
• Use if you want simple mode selection (soft vs fast) plus per‑cell data to evaluate battery health.
• Avoid if you need to charge lithium-ion (e.g., 18650/21700) or larger sizes—choose a chemistry-appropriate charger instead.
• Consider a compact 4‑slot model if you travel ultralight and rarely charge more than a few cells at a time.

Mode guide: pick the right charge

• Soft (gentle) charge: Best for routine charging to limit heat and extend cycle life. Use for most day‑to‑day needs and overnight charges.
• Fast charge: Use when you need cells quickly. More heat is generated, which can shorten lifespan if used constantly—reserve for time‑critical turns.
• Conditioning/Refresh: Runs controlled charge/discharge cycles to rebalance cells that show shortened runtime or inconsistent performance. Use occasionally, not every cycle.

Setup and first use

1. Place the charger on a hard, ventilated surface away from heat sources.
2. Connect the AC adapter. Verify the adapter’s input voltage matches your region if traveling.
3. Select Soft for routine charging; switch to Fast only when turnaround matters.
4. Insert AA/AAA NiMH cells in any combination. The LCD will show per‑slot status.
5. Allow cycles to complete; remove finished cells promptly and let them cool before use or storage.

Battery care with the MH-C940

• Favor Soft mode to reduce heat—heat is the main driver of NiMH wear.
• Let recently used or charged cells cool to room temperature before recharging.
• Group cells used together (e.g., sets of 2 or 4) to keep performance consistent in devices.
• Run Conditioning/Refresh when runtimes drop or cells finish at noticeably different times.
• Store charged NiMH at moderate temperatures; avoid leaving cells in hot cars or in devices long‑term.

Compatibility and safety notes

• Supported: NiMH AA/AAA only.
• Not supported: lithium‑ion (e.g., 18650/21700), alkaline, zinc‑carbon, NiCd, C/D/9V formats.
• Do not charge swollen, corroded, or leaking cells.
• Ensure ventilation; do not cover the unit during operation.
• Unplug when not in use. Keep away from flammable materials while charging.

Troubleshooting

• Cell not detected: Wipe battery contacts, reinsert, or try another slot to rule out debris.
• One slot finishes much sooner: Normal for mixed states/capacities. Use the mAh readout to identify weak cells; run a refresh cycle.
• Charger or cells feel hot: Switch to Soft mode and improve airflow. Remove any obstructions.
• Short runtime persists: Replace aging cells—no charger can restore severely worn batteries.

Specs overview

FAQ

Can I mix AA and AAA in one session?
Yes. Each slot is independent; you can mix sizes, capacities, and states of charge.

Do I need to charge in pairs?
No. Independence means single cells are fine.

Will fast charging damage my batteries?
Occasional fast charges are fine. Routine fast charging adds heat and may reduce lifespan; prefer Soft for daily use.

Does it analyze capacity?
The mAh readout shows how much charge was delivered per cell, which helps compare cells and spot weak ones.

Can it charge lithium‑ion cells?
No. Use a charger specifically designed for lithium‑ion.

Bottom line

If you rely on AA/AAA NiMH batteries, the MH-C940 streamlines charging and diagnostics with eight independent slots, clear per‑cell data, and maintenance modes—helping you keep sets ready with less heat and guesswork.