In short
- A cycle figure is given for specific conditions: depth of discharge, temperature and current.
- Heat is the main enemy of battery life in hot climates; a few degrees less makes a real difference.
- Following the state of health over months shows the actual wear instead of guessing.
Felicity Solar LiFePO4 batteries are sold with a cycle figure in the thousands, at a stated depth of discharge. That figure describes a laboratory test until the capacity falls to a set percentage, often 80 % of the original. The battery does not stop working at that point; it simply holds less.
From cycles to years
One full cycle per day is roughly 365 cycles a year. A household that uses half the battery each night does about half a cycle a day. In those conditions the cycle figure alone points to well over ten years, but calendar ageing and heat also play a part, so real life is usually shorter than the simple maths.
Heat
A battery that lives at 35 °C ages much faster than one at 20 °C. In hot regions this matters more than anything else. Shade, ventilation and a cool room are the cheapest life extension you can buy.
Depth of discharge
Using 100 % every night wears a battery faster than using 70 %. LiFePO4 tolerates deep cycles better than older chemistries, but keeping a reserve at the bottom still helps, and it also protects you during an outage.
Currents
Charging and discharging at high current, close to the battery limit, adds heat and stress. A battery that is sized generously for the inverter works more gently.
Measure, do not guess
The BMS keeps its own estimate of the state of health and counts cycles. Felicity Monitor reads these values through the RS485 port and keeps them in the free Cloud, so you can see the health curve over seasons and compare summer with winter, instead of waiting for the battery to feel weak.
Common questions
Does a Felicity battery stop at the end of its rated cycles?
No. The rating marks the point where capacity has dropped to a set level, often 80 %. The battery keeps working with less capacity.
Is the state of health shown by the BMS exact?
It is an estimate. It is most useful as a trend over months rather than as a single number.
Can Felicity Monitor make my battery last longer?
Not by itself. It shows temperature, cycles and health so you can see what wears the battery and act on it.
