Battery Wiring

Wiring batteries in series can up the voltage while a parallel connection can increase the capacity. Battery manufacturers offer a range of voltages and capacity ratings that will meet most requirements. The considerations that are most important in any installation include capacity in amp-hours (Ah), distance from the inverter and voltage. Choosing a battery configuration depends on your required power load and the expected time of operation during blackouts.

There are manufacturers who offer combined battery/inverter packages for a quick calculation with integrated wiring panels. Beacon Power's Smart Power M5 is grid-interactive while Outback Power Systems offers the PS1-GVFX3648 system which caters for outside installation.

When battery bank size increases (giving more power in long blackouts), short wires will make it difficult to reach the inverter. Use graph paper to plan your battery room layout with cutouts for your chosen battery model: you can shuffle the cutouts around to find the best physical layout. Close attention must be paid to cable connections and run lengths. There must also be adequate wiring planned for disconnecting the battery bank and for protection against excess current. 

The physical size and capacity of the battery may be so large that the distance between the battery bank and the inverter exceeds the cable length recommended by the manufacturer for inverter operation. One way to work around this issue is to use the largest size interconnection wires (#4/0), taping both positive and negative leads lengthwise to lessen cable inductance.

Battery Voltage Regulation

A charge controller can regulate battery voltage. It can be connected as a diversion or series regulator. The latter is the simpler arrangement as it just turns the PV input to the batteries on or off, depending on the charge state. With a wind turbine in your system, you will probably need a generator to support the load with a diversion load or shunt arrangement.