Replace the battery first.

Yes, replace the battery. After six months of daily use, lithium-ion batteries in robot vacuums start losing capacity — especially if you run it until it’s dead every time. That’s normal wear, not a mystery.

But before you order, do a quick sanity check: clean the charging contacts on both the vacuum and the dock, make sure the brush roll isn’t jammed, and check if the filter is clogged. A struggling motor pulls more current and drains the battery faster. If those are fine and the robot still dies early, it’s almost certainly the battery.

Most robot vac batteries are user-replaceable and cost $20–40. That’s cheaper than troubleshooting software, sensor, or main board issues. Try a full discharge + recharge cycle first (sometimes the BMS needs recalibrating), but if that doesn’t help, just swap it.

Start with the battery — it’s the most common culprit and the easiest fix.