Battery:
The Nokia 7610 ships with the BL-5C, which is standard across all current Nokia Series 60 phones. It has a stated capacity of 850mAh and uses Lithium-ion battery technology.
Charging Information:
With thanks to the Battery University
There are three things which should be avoided: total discharge, frequent full discharges, and continuous trickle charging.
The first is where a battery is drained, and is still used. This is dangerous, because lithium-ion batteries can explode if their safety circuits become completely unpowered. However, this will not occur under normal use; simply avoid repeatedly attempting to turn the phone on after it has died due to a lack of battery.
Second, frequent full discharges are frowned upon. To maintain battery condition, it is generally recommended that lithium-ion batteries are charged frequently, even when not near discharge. There is no disadvantage doing this, because lithium-ion batteries do not suffer from memory effect. However, it is necessary to complete a full discharge every 30/50 charge cycles to calibrate the battery.
Third, continuous trickle charging should not in theory hard lithium-ion batteries, but we recommend avoiding this where possible, because of possible residual heat (which reduces battery life) and the fact that storage at 100% charge causes more battery aging that storage at 40% charge.
The aim is to maintain the battery such that capacity loss through internal resistance caused by oxidation is reduced. In any case, it is likely that the battery will die after 2-3 years. There is nothing you can reasonably do to reduce oxidation.
Generally, charge your phone often (e.g. when you get home everyday) and do not allow the battery to go flat, but remove your phone from the charger once it is charged. In addition to this, allow your battery to go flat about once a quarter, to calibrate your battery such that it may hold more charge.
If you are using a new battery:
The general suggestion is to charge for a long period the first time. Frankly, there is no advantage doing this, but there is unlikely to be any concrete harm either. It is also not necessary to let the battery fully discharge and recharge multiple times, although if you feel that your battery life is shorter than it should be doing this once or twice is acceptable. (see the dangers of frequent full discharges above)
Battery Indicator:
The battery indicator is always on the upper right of your phone screen. It is not absolutely linear, but rather works such that after the phone charge has fallen below ~50%, the charge bar begins to move down. Under normal light usage it takes about a day for this to happen, so you will have adequate time to find a charger.
