The battery comes partially charged. Apply a topping charge for 2–3 hours before use. To ensure long battery life do not discharge completely. Recharge the battery every 3 months when not in use. Never leave the battery in the discharged state for long periods. All lithium-ion rechargeable batteries are consumables and have a limited lifespan. Capacity and performance will decline over time. It’s a good idea to have at least one spare battery and rotate their use to ensure consistent work flow. Recharge battery frequently.

The compressor has an auto-off feature: when the gun is connected via the air hose, the compressor will run to reach optimum spray pressure, then rest until the trigger button on the gun is depressed. Battery consumption during auto-off rest is minimal. However, always turn the battery off between jobs to preserve battery life. The battery is designed for a slow charge process (8–10 hours for full charge). An extended, uninterrupted, complete charge extends battery life. 

Battery must be in the ON position when charging. Do NOT use the compressor AC adapter to charge the battery. Damage to the battery will occur. 
There are 5 LED battery-strength indicators. 1 or 2 green lights: Do not run the compressor. Recharge battery prior to use or product application will be compromised. 3,4, or 5 green lights: Sufficient charge to run compressor.