Lithium batteries are unforgiving. Push them past their voltage limit and you lose cycle life. Push them hard enough and you get heat, swelling, and in the worst case a fire. Now imagine charging an entire AGV or AMR fleet automatically — no human standing by to watch the curve and stop the process when something is off.
That is the job of the charging algorithm inside an industrial wireless charger. The method every ONEPOINTECH industrial power system specifies is constant current / constant voltage (CC-CV). Our LS300-A60 3kW system and LC180-A30 1.5kW system both list "Charging method: Constant current and constant voltage" on the datasheet.
In this guide, we'll break down what that actually means, why it exists, how it plays out in a real wireless charging session, and what to check on your battery before you spec a charger.
What CC-CV Charging Means
CC-CV is a two-phase charging curve. It is the standard, safe way to charge lithium and most other rechargeable batteries, and it looks like this:
| Phase | What the charger does | What the battery does | Why it exists |
|---|---|---|---|
| 1. Constant Current (CC) | Delivers a fixed current (e.g. 60A on the LS300-A60) | Voltage rises as the pack fills | Bulk charge — delivers most of the energy in the shortest time |
| 2. Constant Voltage (CV) | Holds the voltage at the chemistry set point (e.g. 58V) | Current tapers down as cells approach full | Top-off — prevents overcharging and cell stress |
| 3. Charging complete | Stops when current drops to the threshold (or the BMS says done) | Pack sits at full | No trickle overcharge, no battery damage |
A useful way to picture it: filling a cup. Constant current is the tap wide open while the cup is still mostly empty. Constant voltage is throttling the flow to a trickle as the water nears the rim so it doesn't spill. The charger knows when to switch because it measures the battery voltage and current at its output in real time.
Why Lithium Batteries Need This Curve
Lithium cells have a narrow safe operating window. Each chemistry has a hard upper voltage — for LiFePO4 packs that is typically 58V for a 16S arrangement, and for Li-ion it is around 4.2V per cell. Two things happen when a charger ignores that limit:
- Overcharge: pushing voltage past the set point causes lithium plating and dendrite growth inside the cell. That permanently shrinks capacity and, in the worst case, creates an internal short — a fire risk.
- Stress and heat: forcing current in the wrong phase heats the cells and accelerates aging. Fleet batteries are expensive; every lost cycle is real money.
This is why the BMS (battery management system) is always in control. The charger does not decide the voltage on its own — it waits for a charging command and the set voltage from the vehicle's BMS, then executes the CC-CV curve against it. If the charger and battery don't agree on the curve, you shouldn't plug them together.
How CC-CV Plays Out in a Wireless Charging Session
Wireless charging only replaces the physical connection. The algorithm runs identically on the receiver side, measuring the real voltage and current at the output. Here is the actual charging logic from the LS300-A60 and LC180-A30 datasheets:
- The receiver coil docks onto the transmitter coil.
- The charger and vehicle establish a 2.4G communication link and recognize each other (multi-machine recognition completes in under 10 seconds on the LC180).
- The system enters a "rechargeable" standby state, waiting for a CAN command from the vehicle — no external boot signal is needed, the vehicle just docks.
- Once commanded, charging starts in constant current. The charger ramps up and delivers current (current rise time is under 20 seconds on the LC180), and the battery voltage climbs.
- When the voltage reaches the set value, the charger switches to constant voltage. Current tapers as the pack fills.
- Charging completes, the fan stops, and the vehicle can drive away.
Throughout the session the charger broadcasts a CAN frame with output voltage, current, temperature, and coupling degree, so the fleet system can see what is happening in real time. It also performs auto-detect self-starting — the moment a vehicle is in range, it is ready, no button presses.
Why This Matters for Opportunity Charging
Most AGV and AMR fleets do not charge from empty to full in one long session. They dock for ten or fifteen minutes during natural stops — loading, waiting, picking. That is opportunity charging, and it is exactly what wireless is built for.
Short sessions mostly live in the fast constant-current phase, which is where the battery recovers the most energy per minute. Because lithium handles partial cycles well, the pack can cruise in a working band (roughly 20–80%) instead of always needing to reach 100%. The charger starts and stops automatically as vehicles dock and undock, so there is no human in the loop and no connector to wear out.
For fleets, the practical result is smaller batteries, higher uptime, and a charging curve that keeps those expensive packs healthy for years — all without anyone checking on the charge.
What to Check on Your Battery Before You Spec a Charger
CC-CV only works if the charger and the battery agree. Before you compare chargers, write down these five things:
- Battery chemistry and cell count — this defines the target voltage. The charger output window must cover it: our LS300-A60 outputs 42–58V and the LC180-A30 covers 18–60V (compatible with 24V, 36V, and 48V systems).
- BMS communication protocol — does your BMS speak CAN (or RS485), and can the charger receive its charge command and set voltage? Both our systems support CAN/RS485.
- Maximum charge current vs. battery C-rate — never let the charger exceed the BMS limit. The LS300 adapts 10–60A; the LC180 outputs up to 30A.
- Partial-cycle behavior — if you plan opportunity charging, confirm the charger is happy to start, stop, and restart repeatedly without a full discharge.
- Output ripple — clean DC output protects battery health. Our power systems spec ripple tightly (about ±3.5% on the LS300, around ±1% voltage ripple on the LC180).
Conclusion
CC-CV charging is the quiet piece of engineering that keeps industrial battery packs safe and long-lived. In a wireless system it runs automatically — the vehicle docks, the charger recognizes it, follows the BMS curve, and reports back over CAN — with no human in the loop.
If you are sizing a wireless charger for an AGV, AMR, or forklift fleet, send ONEPOINTECH your battery details: chemistry, cell count, capacity, maximum charge current, BMS communication protocol, air gap, and target charge time. We can match you to a 3kW system like the LS300-A60, a 1.5kW system like the LC180-A30, or a custom build that fits your voltage window and charging curve.
Need a recommendation? Email info@onepointech.com with your battery spec and duty cycle — our engineering team will help you pick the right wireless charging solution.