Robot mower battery life means two different things: minutes of mowing per charge and the years a pack remains useful. You need both figures to plan ownership, but neither tells you how much lawn the mower can maintain by itself.
Reviewed September 28, 2026. This is a documentation-based guide, not a battery endurance test. Manufacturer examples apply to the named model or range; the log and calculations below are tools for your own observations.
How long should the battery last?
Husqvarna gives a typical lifespan of 2–5 years for Automower batteries, with use and care affecting the result. That is a brand’s guidance, not a replacement deadline for every robot mower. Its support article identifies increasingly frequent charging and stopping with an empty battery as possible signs of ageing, and recommends dealer help with replacement. See Husqvarna’s battery lifespan guidance.
For one concrete runtime example, the UK Automower 310 Mark II specification lists 60 minutes of typical mowing and 60 minutes of typical charging. These are separate parts of its operating cycle. A four-hour schedule is not four hours of cutting.
Compare runtime together with charging time
A useful first calculation is:
Approximate mowing share = mowing minutes ÷ (mowing minutes + charging minutes).
| Input | Mower A | Mower B |
|---|---|---|
| Mowing per charge | 50 minutes | 80 minutes |
| Charging | 50 minutes | 40 minutes |
| Mowing share | 50% | About 67% |
| Mowing within a six-hour window, simple estimate | 180 minutes | 240 minutes |
This simplified calculation excludes travel to the dock, waiting, interruptions and the charge available at the beginning and end of the window. It also says nothing about cutting width or how efficiently the mower covers a lawn. Use it to spot a scheduling constraint, then check the manufacturer’s area rating and daily operating restrictions. Our robot mower buying guide covers the wider fit.
Build a useful baseline before buying a replacement
Comparing today’s run with an old memory of “about an hour” can be misleading. Record several ordinary cycles using the same definition of runtime. For example, measure from leaving the dock to beginning the return trip, rather than including the search for the charger on one day but not another.
| Record | Your observation | Why it helps |
|---|---|---|
| Model, battery age and firmware version | Fill in | Keeps comparisons tied to the same equipment. |
| Date, zone and grass conditions | Fill in | Separates a changed workload from a persistent decline. |
| Departure, return-start and docking times | Fill in | Separates mowing from the journey home. |
| Charge duration and reported charge level | Fill in | Shows whether each run begins after a completed charge. |
| Exact stop reason or error message | Fill in | A scheduled stop is different from an empty-battery stop. |
Example: a change from 60 to 45 minutes is a 25% reduction in observed runtime: (60 − 45) ÷ 60 × 100. It is not proof of 25% battery-capacity loss. Different cutting conditions, an interrupted charge or different logging boundaries can produce a similar result.
What should you investigate first?
- The mower reaches its dock but does not complete charging: use the charging troubleshooting instructions for that model. A failed charge does not establish that the pack needs replacing.
- It cuts normally but spends much longer getting home: record that travel time and inspect the route or installation. See the charging-station return guide.
- Shorter runs persist under comparable conditions: send your log, battery age and error history to the manufacturer or dealer. Ask how they assess battery condition and whether the proposed remedy addresses the recorded symptom.
Do not deliberately run the pack flat to “reset” it, or assume that a firmware update requires several deep discharge cycles. Use a calibration procedure only if the manufacturer specifies one for your mower.
Plan care and replacement separately
Husqvarna’s battery guidance recommends a cool or shaded charging location, cleaning the mower and following its winter-storage instructions. Storage charge requirements must come from your model’s manual; a generic lithium-ion tip may conflict with it. See our winter storage checklist.
If the battery is damaged, stop using it and arrange manufacturer guidance; do not open the pack. The 305/310 Mark II/315 Mark II manual, section 1.6, specifically prohibits using a damaged battery or dismantling it.
Before authorizing replacement, obtain the correct part number and a quote covering fitting and any required setup. Put that quote in your ownership-cost worksheet. A useful battery is one that still supports the required mowing schedule safely; age alone does not make that decision.
Update — September 28, 2026: Separated runtime from battery lifespan and replaced unsupported diagnostic thresholds with a measurement log.