Page
11/55
The charge process is fundamentally different to that required for Ni-Cd or Ni-MH batteries, and is
termed a constant current / constant voltage method. The charge current required varies according to
the battery capacity, and is set automatically by the charger. Lithium batteries are usually charged at
the 1C rate (1C charge rate = half capacity as charge current. Example: battery capacity 1500 mAh:
1C charge current = 1500 mA = 1.5 A).
Because some types can be charged with up to 2C or 4C charging current, the charging current and
the capacity of the battery must be set separately. When the battery on charge reaches the specific
final voltage which is appropriate to the battery type, the charger automatically reduces the charge
current in order to prevent the battery exceeding the final permissible voltage. If the battery
manufacturer states a charge current lower than the 1C rate, then the capacity (charge current) must
be reduced accordingly.
We recommend the use of the balancer connector, which ensures that your Lithium batteries
are charged optimally, and therefore increases safety and their useful life.
Problems caused by mistreating batteries:
It is very dangerous to overcharge Lithium-Ion batteries, as they tend to react by gassing, overheating
and even exploding. If the final charge voltage of 3.6 V / cell (LiFePO4), 4.1 V / cell (Lithium-Ion) or 4.2
V / cell (Lithium-Polymer and Lithium-Manganese) is exceeded by more than 1%, the lithium ions in
the cell start to change into metallic lithium. This material reacts very violently with the water in the
electrolyte, and this can result in the cell exploding. On the other hand it is also important to avoid
terminating the charge process before the final charge voltage is reached, since this reduces the
effective capacity of the Lithium-Ion cell markedly. Stopping the charge at just 0.1 V under the
threshold means a capacity loss of around 7%. Lithium batteries must not be deep-discharged, as this
leads to a rapid loss of capacity. This effect is irreversible; it is absolutely vital to avoid discharging the
batteries to below 2.5 V / cell.
Caution: the cell type, cell capacity and cell count set on the charger must always be correct
for the battery to be charged; if you make a mistake, the battery could explode and burn! Never
connect a Lithium-based battery to the charger if it features an integral charge circuit! Always
place your Lithium batteries on a non-flammable surface for charging.
The fundamental rule is that Lithium-based batteries may ONLY be
charged using special chargers, and the charge program must be
set up correctly in terms of final charge voltage and capacity for the
battery type in use.
Charging Time
Voltage
current
Содержание 6478
Страница 13: ...Page 13 55 ...
