Xantrex Technology SW Series owner manual Series - Parallel Connection, Page 108, 12V INVERTER

TECHNICAL INFORMATION

PARALLEL CONNECTION

Batteries are connected in parallel when all the positive terminals of a group of batteries are connected and then, separately, all the negative terminals are connected. In a parallel configuration, the battery bank have the same voltage as a single battery, but an amp/hour rating equal to the sum of the individual batteries. This is usually only done with 12-volt battery-inverter systems.

12V

12V 12V 12V

FUSED

DISCONNECT

12V INVERTER

(Total Battery Capacity

= 200 Amp Hours)

Each individual 12-volt battery capacity = 50 amp hours

Figure 33, Parallel Configuration: 12-Volt Battery Wiring

SERIES - PARALLEL CONNECTION

As the name implies, both the series and parallel techniques are used in combination. The result is an increase in both the voltage and the capacity of the total battery bank. This is done very often to make a larger, higher voltage battery bank out of several smaller, lower voltage batteries. This is common with all battery-inverter system voltages. The smaller, lower voltage batteries are first connected in series to obtain the needed voltage, then these ‘batteries, connected in series’ sets are connected in parallel to increase the battery bank capacity.

The best arrangement when using a series-parallel configuration is to connect all the smaller, lower voltage batteries in parallel, then connect all these ‘batteries in parallel’ into series sets to obtain the needed voltage. This configuration is often called “cross-tying”. This is less convenient and requires additional cables but reduces imbalances in the battery, can improve the overall performance and in a “shorted cell” scenario, would cause only the battery(s) that are actually in parallel with the “shorted” battery to discharge. This would allow you to re-configure your battery bank with the other batteries that are in parallel with the shorted/discharged battery(s) and still be operational only at a lower capacity.

The more efficient “cross-tying” method is shown in Figure 34 and Figure 35 as “dash” (- - -) lines. If “cross-tying” is not desired, the dash lines shown may be ignored.

Page

108

 2001 Xantrex Technology, Inc.	Telephone: 360/435-8826	SW Series Inverter/Charger
5916 - 195th Street N. E.	Fax: 360/435-2229	Part No. 2031-5
Arlington, WA 98223	www.traceengineering.com	Rev. C: February 2001