Xantrex Technology PROwatt 1000 Charging System Requirements, Charging With an Engine Alternator

Alternators and Charging Systems

Charging System Requirements

Your charging system should be capable of delivering a charging current equal to 25% of the amp-hour capacity of your battery. For example, if you have a 200 Ah battery, the charging system should be able to deliver 50 amps. The charging system must also be able to charge each 12 volt battery up to approximately 14.4 V and then drop back to a “float” voltage of 13.5–14 V (or shut off).

CAUTION

Never operate the PROwatt 1000 directly from an alternator. To work properly, the inverter must be connected to a battery or a well-regulated, high-current DC power supply.

Charging With an Engine Alternator

Read the following information to determine whether your vehicle’s standard alternator will be adequate by itself, whether you should install an alternator controller, or whether you need a high-output alternator.

Using a Standard Vehicle Alternator

A typical engine alternator (12 volts) may not be able to meet the requirements outlined above if your system uses large capacity batteries. Alternators are typically rated for the current they can deliver when they are cold. In use, alternators heat up, and their output current capability drops by as much as 25%. Therefore, standard alternators with ratings of 40–105 amps only deliver a maximum of 30–80 amps in actual use and deliver even less as battery voltage rises. Many alternators cannot produce more than 13.6 volts when they are hot. As a result, a standard alternator may not be able to charge a large battery quickly and completely.

Two solutions are to install an alternator controller or to install a high- output alternator.

C–2