Start by identifying your device type and what you need to know: actual capacity, health, or remaining runtime. Match the approach to the task: built in indicators work for quick checks on wearables, handheld testers suit small devices, while professional testers are best for larger systems such as outdoor lighting. Consider battery chemistry (Li-ion is common in wearables), voltage ranges, and the required accuracy. For example, a smartwatch battery around 250mAh may be checked with a simple handheld meter, while a solar street lamp with a larger inbuilt pack may require more robust equipment. If you’re choosing between Tecno wearables or Bolaimei chargers, think about the typical usage and detector compatibility.