Backup Charging Logic
1. Overview
The device automatically applies different charging strategies based on the battery State of Charge (SOC), Backup Reserve, and Recharge Source. The main objectives are:
- Maintain a minimum Backup Reserve to prevent over-discharge
- Prioritize solar (PV) charging whenever possible
- Introduce AC charging when necessary to improve system recovery
- Avoid frequent switching near critical SOC thresholds
Depending on the selected Recharge Source, the system automatically operates in one of the following modes without manual intervention:
- PV + AC: Prioritizes PV charging; when PV power is insufficient, the system supplements with grid (AC) power
- PV Only: Charges the battery using PV as the primary source
👉 App steps: Device page → Select your device → Tap 
→ SoC Settings → Set Backup Reserve (5%–100%)
2. PV + AC
When the Recharge Source is set to PV + AC, both AC and PV can be used for charging.
👉 App steps: Device page → Select your device → Tap → SoC Settings
- Set Recharge Source: Select PV + AC
- Set Recharge Power: Configure AC charging power (default: 500W)
- SolidFlex/PowerFlex 2000: 100W–2400W
- BK1600/BK1600 Ultra: 100W–1200W
Operating Logic
| Battery SOC | System Status | Behavior Description |
|---|---|---|
| Above Backup Reserve | Normal | Battery charges and discharges normally |
| = Backup Reserve | Protection | Stops discharging; PV can still supply loads |
| < Backup Reserve - 2% | Recharging | PV + AC charge simultaneously for fast recovery |
| Back to Backup Reserve | Stop AC | Stops AC charging; PV charging continues |
| > Backup Reserve + 2% | Normal | Battery discharging resumes |
3. PV Only
When the Recharge Source is set to PV Only, the system prioritizes PV charging.
Under normal conditions, AC charging is not actively used. However, in extremely low SOC scenarios, protective AC charging may still be triggered.
👉 App steps: Device page → Select your device → Tap → SoC Settings
- Set Recharge Source: Select PV Only
Operating Logic
| Battery SOC | System Status | Behavior Description |
|---|---|---|
| Above Backup Reserve | Normal | Battery charges and discharges normally |
| = Backup Reserve | Protection | Stops discharging; PV can still supply loads |
| < Backup Reserve - 2% | PV Charging | Only PV is used for charging |
| ≈ 3% (total SOC) | Critical Protection | PV + AC charging is automatically enabled |
| ≥ 5% (total SOC) | Exit Protection | Stops AC; returns to PV-only charging |
| > Backup Reserve + 2% | Normal | Battery discharging resumes |
4. Differences Between the Two Modes
| Scenario | At Backup Reserve | Below Backup Reserve - 2% | Low SOC Protection | Resume Discharge Condition |
|---|---|---|---|---|
| PV + AC | Stop discharging; PV supports load | PV + AC charging | - | Battery SOC > Backup Reserve + 2% |
| PV Only | Stop discharging; PV supports load | PV only charging | At 3% total SOC: PV + AC enabled; at 5%: AC stops | Battery SOC > Backup Reserve + 2% |