Lithium-ion batteries have a limited lifespan (like all rechargeable batteries). Each WaterMate user pushes their system to different levels, but as a very general rule, a WaterMate battery will last from 12 months (when pumping the maximum of 10 minutes every day) upwards.
If you're only pumping 5 minutes a day, expect 24 months / 2 years, and so on.
Other factors such as heat will affect battery life. An excessively hot environment will significantly reduce lifespan, so keep your control unit cool. Practically, in a greenhouse or polytunnel this means in the shade.
Control units from V9 upwards can measure the health of the battery using the ISR value, which can be seen on the Device Control Panel under "Battery info".
- A new battery will have an ISR around 0.2
- If ISR is below 0.3, the battery is still OK.
- Above 0.3, the battery could do with being replaced.
- Above 0.4 and you definitely need a new battery.
Note that your firmware will need to be 2024050200 or above to monitor the ISR.
See WaterMate firmware updates for more info.