Page 127 - TBIS_15194-2019_(EN)_3nd

TBIS 15194:2019

Annex A
(informative)
Example of recommendation for battery charging

Safety and quality of battery charging can be greatly improved by sensing the battery
temperature during charging.

Most battery charger manufacturers set their chargers to have an optimal ambient
temperature of 20 °C to 25 °C. Lower temperatures result in under charge, higher
temperatures result in over charge.

While it is normal when building battery packs from Ni-Cad, Ni-Mh and Li-ion battery
cells, to include temperature sensing, this is not always the case with valve regulated

lead acid (VRLA) batteries.

The main reason for including temperature sensing in VRLA batteries is to protect
against one or more cells within the battery pack becoming short circuited. This
lowers the terminal voltage and can allow the charger to supply more power than is
required, which can lead to a dangerous thermal situation.

Temperature sensors should be fitted to each battery within the pack and this
information fed back to the battery charger.

It is recommended that positive temperature coefficient (PTC) thermistors are used.
All thermistors should be connected in series between the charger temperature pin
(T) and the battery pack negative pin (-). Should any battery or cells within the pack

reach the temperature given by the battery manufacturer (e.g. 60 °C, 70 °C…) the
charger thermal detection circuitry should be adjusted to detect this condition and
take suitable measures to stop any further increase in temperature.

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