CAIRE SAROS 3000, Service Manual

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Service Manual
14 | MN260 B
RECHARGEABLE BATTERY
The Battery allows operating the SAROS away from AC or DC power. The Battery used with
the SAROS contains Lithium Ion battery cells, similar to those used in laptop computers and
cell phones. The SAROS Battery is approximately 87.6 W-hours in capacity and provides
an output voltage of 12V to 16.6V. The Battery connects to the bottom of the SAROS and is
secured by a mechanical latching mechanism. The Battery can be recharged when the SAROS
is connected to the AC Power Adapter or the 24 VDC Cable. The Battery Gauge indicator on
the SAROS LCD will have a “waterfall” effect when the Battery is charging. The fastest way
to recharge the Battery is using the AC Power Adapter.
The Battery has an integral safety circuit that prevents over charge, over discharge or damage due to an external short circuit
of the pack. An Integral fuel gauge communicates battery voltage, current, charge state, and temperature. Based on the voltage
supplied by the Battery, the system is configured to optimize battery charging by regulating the charging voltage and current as
follows:
Battery Pack Output Voltage (VDC) Charging Voltage (VDC) Charging Current (A)
< 10.0 FAULT FAULT
10.0 – 11.9 16.6 0.55 to 0.70
> 12.0 16.6 5.60
Table 1-1. Battery Pack
When the SAROS is operating on Battery power, the LCD displays an estimate of the amount of time the unit can operate at the
current settings, /- 5 minutes. When the SAROS is operating on Battery and the time on battery falls below 15 minutes,
the LCD time on battery characters will flash to indicate a low battery condition.
The capacity of the SAROS Battery is determined by electronics and software. While the SAROS Battery allows the concentra-
tor to operate at its full range of capabilities, the primary purpose of the Battery is to allow an autonomous system while moving
between AC or DC power sources. The SAROS’s Battery, like all lithium ion batteries, is susceptible to permanent damage from
excessive heat. Exposure to excessive heat may shorten the Battery’s service life. Other than excessive heat, other factors
influence Battery life, such as the number of Charges/Discharges that the battery has been undergone. CAIRE Inc. advises that a
typical service life of a battery is 80% Nominal Capacity after 200 Charge/Discharge cycles.
The Battery contains multiple temperature sensors to monitor battery cell temperature. The amount of heat the Battery can safely
endure varies depending on how the Battery is being used. During discharge, the SAROS software will shut the system down if
internal battery cell temperature exceeds 59°C. While the Battery is charging, software will interrupt charger operation when the
internal battery temperature exceeds 40°C or temperature is less than 5°C. In both of these cases, when internal battery cell tem-
perature returns within these limits, the SAROS will resume normal operation. Operation near these temperature limits will not
damage the Battery, but are in place to ensure that the service life of the Battery is preserved.
Heat in the Battery is generated during discharge, and can also be the result of operating the SAROS in high ambient tempera-
tures. The amount of internally generated heat varies with the flow setting – higher flows induce greater Battery heating. While
high ambient temperatures are typically the result of operation on a hot day, running the SAROS with inadequate ventilation can
also cause additional heat. Always ensure that the SAROS is operated in a well-ventilated space, the Air Inlet Filter is clean, and
intake and exhaust vents are unobstructed.
CHARGING ALGORITHM
The charging algorithm is performed by the Power Board software and involves three basic decisions:
1. When to start charging
2. How fast to charge
3. When to stop charging
Charging begins when Battery voltage falls below 90% relative capacity. The charging current is limited by the charger capabil-
ity and the rated capacity of the Battery. Under certain conditions, the SAROS may not have enough external power available to
charge the batteries at the full rate. In this case, the charging rate will be limited to the available power. As the Battery accumu-
lates charge, the charging current required will eventually fall. Battery charging will cease when the Battery voltage is greater
than 16V, charge current is less than 0.66A, and relative charge is greater than 93%.