Power Inverters FAQ - Answers

Power Inverters FAQ - Answers

How long will the inverter run on batteries?

The inverter will run continuously if: The battery(ies) voltage maintains 11 volts (10.5 volts for GO-AC models) or higher (15.5 volts max 16 volts max for GO-AC models). Sufficient air spacing and ventilation around the inverter Not unusually high air temperatures (90+) Wattage is below continuous rating of inverter To determine how long a typical battery will last we need to find the amp/hour rating of the battery. The cold cranking amps or CCA rating is only a number to compare manufacturer's batteries. Somewhere on the battery labeling there should be a "reserve minutes" specification. Simply times the "reserve minutes" number by .3 to get an amp/hour rating for the battery. For example; What is the amp/hour of a battery with 100 reserve minutes? 100 x .3 = 30 amp/hours How long will a battery last? A 300 watt inverter providing 150 watts connected to a fully charged 100 reserve minutes battery will last approximately 2 hours. To determine the power the inverter needs from the battery click here. 30/15 amps = 2 hours The higher the "reserve minutes" the longer the inverter will work.

Vehicle Electrical System (alternators)

A major consideration when installing large inverters (500 Watts and higher) is the charging system. The charging system must be able to keep ahead of the current drain from the inverter plus the drain of the remaining systems in the vehicle. Normal vehicle alternators range from 65 to 90 amps. For example a 1500 watt inverter supplying power to a 1000 watt appliance requires 100 amps from the battery. With the vehicle's alternator rated at 90 amps, this is a 10 amp drain for the battery. Using the above battery, the car will be dead within 3 hours! Not only will the car be dead but the alternator may burn out because it was trying to recharge the battery at its full output. Alternators do not like to work full out. A larger alternator, at least 20 to 30 amps more than what's needed will be required to keep the battery charged. A 110 or 120 amp alternator would be required in this application. If the 1500 watt was used at its continuous rating a 170 to 180 amp alternator is needed. Choosing The Right RV Batteries - Solar RV Panels Charging, Recharging and Monitoring Your RV Batteries - Solar RV Panels