A: No. The standard BST900W does not support parallel operation. Doing so will destroy both units. Check your specific revision – some "Pro" models allow it, but the base manual forbids it.
| Parameter | Function | Default | Recommended Setting | | :--- | :--- | :--- | :--- | | P01 | Low-voltage shutdown threshold | 10.5V | 11.0V (prevents battery damage) | | P02 | Output frequency | 60Hz (US) / 50Hz (EU) | Set to your region | | P03 | Power-saving mode | OFF | OFF (ON can cause slow wake-up) | | P04 | LCD brightness | 80% | 60% (reduces idle draw) | | P05 | Battery type | AGM | Lithium (if using LiFePO4) | bst900w manual
A: Normal. The BST900W continues cooling internal components until temperature falls below 45°C (113°F). This can take 2-5 minutes. Check your specific revision – some "Pro" models
Even if the LCD shows 3 bars, the manual insists on a full charge. Plug into wall AC for 6-8 hours. The indicator will show "100%" or "FULL". This can take 2-5 minutes
Plug in a 40W–100W device (e.g., a lamp or phone charger). Do not test with a high-draw device like a heater. The manual recommends always starting with a low-wattage test. Part 5: Decoding the LCD & Control Panel (Visual Reference) The BST900W manual dedicates a full page to the LCD symbols. Here is the cheat sheet: