The four official rules
Most G1 “charging failures” are one of these requirements from the official battery/charger manual being violated:
- The battery must be OFF before charging. Charging a powered-on pack is the most common miss — power it down first.
- Official Unitree charger only. Third-party chargers aren’t just unsupported; voltage mismatch is a fault and a fire risk. Also verify your mains voltage matches the charger’s nameplate rating.
- Never charge a hot battery. Straight off a run, the pack is above safe charging temperature — let it cool to room temperature first. A battery that refuses to charge right after a session is behaving correctly.
- Charge between 5–40°C ambient. A garage in winter or a car trunk in summer is outside the window, and the pack will refuse or underperform.
If the rules check out and it still won’t charge
- Inspect the charge port and connector for debris or bent pins (look, don’t probe).
- Try the charger on a second battery if you have one — it isolates pack vs charger. A dead charger indicator light points at the charger.
- Long-stored batteries can deep-discharge. This is documented for Unitree packs: a battery left unused for months may drop below recoverable voltage, and the fix is replacement through Unitree support, not repeated charge attempts.
The economics
Unitree sells replacement batteries (the Go2 pack starts at $500; G1 pack pricing is quote-based via their parts channel), and roughly one-hour-per-charge runtimes mean the battery is the G1’s most-stressed component. Storage tip from the deep-discharge cases: don’t leave packs at empty, and don’t store them for months untouched.