SEALED ENERGY SYSTEMS
®
19
User Manual
3.3.10. Pack Calibration cycle
The fuel-gauge uses the Impedance Track Technology to measure
and calculate the available charge in battery cells. The achievable
accuracy is better than 1% error over the lifetime of the battery. Max
Error increases by 1% in 20 cycles, e.g., only occasionally is a full
charge/discharge learning cycle required to maintain high accuracy.
3.4.
Protection Electronics
3.4.1. Overview of Operations
Electronic circuitry is permanently connected within the battery pack
to prevent damage if either the charger or host device fails to
function correctly. The circuitry also protects the battery if an illegal
current source is placed across the battery terminals, or an illegal load
is connected. Redundant levels of protection have been implemented
(the primary protection levels are auto-resettable and the secondary
are non-resettable).
3.4.2. Charge Protection
Over-Voltage:
The primary protection circuit will prevent the battery from
charging if any cell voltage >= 4300mV. Then, once all cell
voltages are <= 4150mV, it will allow charging again.
The secondary protection circuit will prevent the battery from
charging if any cell voltage >= 4.35V +/-0.05V by blowing a
power path logic fuse. The fuse is non-re-settable rendering
the battery pack non-functional.
Over-temp:
The primary protection circuit also provides over-temperature
protection and will prevent the battery from charging at
temperatures =>54ºC (see paragraph 3.1.5 for Charge
Current() request). Then, once the battery temperature has
cooled to <=45ºC, it will again allow charging.
Over-Current:
The primary protection circuit also provides continuous over-
current protection and will prevent the battery from charging
at Current() =>2.9A*. Then, once the Average Current() <=
200mA for 70sec, the battery will re-test the over-current
condition, and again allow charging.
*Note: Current values vary time to time. Check SDS with SES®
