Talktime
Talktime is usually measured in hours for any rechargeable communications device (mobile phone or cordless phone).
This is the maximum expected duration a fully charged battery is expected to last under perfect conditions (ambient temperature has a major impact on battery life).
Talk time is the officially quoted longest time that a single battery charge will last when you are constantly talking on the phone. The talk time is highly dependent on the cellular network environment such as the distance to the closest GSM cell tower. Moving fast while talking (as in a vehicle) also negatively affects battery life.
Manufacturers measure talk time in controlled conditions and the quoted numbers are rarely reached in real-life scenarios. These numbers are best used as reference when comparing phones from the same manufacturer because battery life measurement methodology will probably vary from manufacturer to manufacturer.
A safe rule of thumb is to use the following guide to expected talktimes as your phone battery ages (the last column has a specific example of 12 hours talktime):
| Age | fraction of max | percentage est. | talktime |
|---|---|---|---|
| under 1 year | 3/4 | 75–85% | 9–10 hours |
| 1–2 years | 2/3 | 66–75% | 8–9 hours |
| 2–3 years | 1/2 | 50–66% | 6–8 hour |
| 3–4 years | 1/3 | 33–50% | 4–6 hours |
| over 4 years | 1/4 | 25–33% | 3–4 hours |
Most phone batteries don't last more than 4–5 years and have to be replaced by then.
Talktime is different from the standby time of the device, which is always much longer.