Battery Care And Maintenance; Table 6, Battery Charging: Charging Setpoints - Xantrex SW Series Owner's Manual

TECHNICAL INFORMATION

BATTERY CARE AND MAINTENANCE

If you have read the battery charger mode section of this manual, you already have a good idea of the
stages of battery charging that combine to promote fast charging and ensure long battery life. Basically,
there are five charger-related considerations to properly care for your batteries.
Charge Rate - The maximum safe charge rate is related to the size and type of your batteries.
Standard vented lead acid batteries (with battery caps) can be charged at a high rate - equal to their
capacity. Small batteries may require a lower charge rate. Check with the battery manufacturer. Adjust
the MAX CHARGE AMPS AC setting to control the charging rate.
Bulk Voltage - This is the maximum voltage the batteries reach during the normal charging process.
Gel cell batteries are usually set to a lower value, while non-sealed batteries are set to the higher.
Adjust the SET BULK VOLTS DC setting to control the battery voltage during the BULK and
ABSORPTION stages.
Float Voltage - The batteries experience less gassing if they are maintained at a lower voltage than the
voltage at which they are charged. Adjust the FLOAT VOLTS DC setting to control the battery voltage.
Temperature Compensation - Temperature affects the optimum voltage values for the bulk and float
charging stages. The Battery Temperature Sensor (BTS) automatically fine-tunes these voltages for you.
Equalization (Non-Sealed Batteries Only) - Many experts recommend that batteries be "equalized"
(A fancy term for over-charged) every month or two. However, a leading battery manufacturer
recommends equalizing only when low or wide ranging specific gravity (± 0.015) are detected after
fully charging a battery. Since the individual battery cells are not exactly identical, some may still have
sulfate on their plates after a complete charge cycle. On the other hand, if the batteries never received
a full charge, all plates will have sulfate left on them. If the sulfate remains on the plates for an
extended period of time, it will harden and seal off a percentage of the plate area, reducing the
capacity of the battery. By equalizing the batteries, the entire sulfate is removed from the plates.
Additionally, the gassing that result stirs up the electrolyte which tends to stratify. Stratification
concentrates the sulfuric acid in the bottom of the cell while the top becomes watery. This corrodes
the plates. Equalization is accomplished by charging batteries above a voltage of 2.6 VDC per cell.
This is over 15 VDC for a 12 VDC system, 30 for a 24 VDC system and 60 for a 48 VDC system.
Since equalizing is basically overcharging the battery, which can be harmful to battery's life and
performance, it is done only when required.
CAUTION: Equalization should be done only with standard electrolyte batteries. If you
have sealed or gel cell batteries, check first with the battery manufacturer before
equalizing. DC loads should be disconnected before equalization to protect them from damage
by the high battery voltage involved.
TYPICAL BULK AND FLOAT SETPOINTS FOR COMMON BATTERY TYPES
Battery Type
Sealed Gel
Lead Acid battery
A.G.M.
Lead Acid battery
Maintenance-Free RV/Marine
Lead Calcium Battery
Deep-Cycle, Liquid Electrolyte
Lead Antimony Battery
NiCad or NiFe Alkaline Battery*
(using 10 cells in series)
Note: Values shown are for 12-volt systems. For 24-volt systems, multiply the settings shown by
two. For 48-volt systems, multiply the settings shown by four. These settings are guidelines, refer to
your battery manufacturer for specific settings.
2001 Xantrex Technology, Inc.
Page
5916 - 195th Street N. E.
104
Arlington, WA 98223

Table 6, Battery Charging: Charging Setpoints

Bulk Volts Float Volts
14.1 VDC BULK 13.6 VDC FLOAT
14.4 VDC BULK 13.4 VDC FLOAT
14.4 VDC BULK 13.4 VDC FLOAT
14.6 VDC BULK 13.4 VDC FLOAT
16.0 VDC BULK 14.5 VDC FLOAT
Telephone: 360/435-8826
www.traceengineering.com
Equalizing Charge Process
Not Recommended - Consult manufacturer
Charge to 15.5 VDC or as per manufacturer
Not Recommended - Consult manufacturer
Charge to 15.8 VDC or as per manufacturer
Consult manufacturer
Fax: 360/435-2229
SW Series Inverter/Charger
Part No. 2031-5
Rev. C: February 2001