Tripp Lite DC-to-AC Inverter Application Guide, Example, Tools, Appliances, × 1.2 = 270 Amp-Hours

Application Guide

Match Battery Amp-Hour Capacity to Your Application

Select a battery or system of batteries that will provide your Inverter with proper DC voltage and an adequate amp-hour capacity to power your application. Even though Tripp Lite Inverters are highly efficient at DC-to-AC inversion, their rated output capacities are limited by the total amp-hour capacity of connected batteries and the support of your vehicle’s alternator if the engine is kept running.

Example

• STEP 1: Determine Total Wattage Required

Add the wattage ratings of all equipment you will connect to your Inverter. Wattage ratings are usually listed in equipment manuals or on nameplates. If your equipment is rated in amps, multiply that number times AC utility voltage to determine watts. (Example: a ¼ in. drill requires 2½ amps. 2½ amps × 120 volts = 300 watts.)

Note: Your Inverter will operate at higher efficiencies at about 75% - 80% of nameplate rating.

Tools

¼" Drill Orbital Sander Cordless Tool Charger

300W	+	220W	+	20W	=	540W
		Appliances
Blender		Color TV		Laptop Computer
300W	+	140W	+	100W	=	540W

• STEP 2: Determine DC Battery Amps Required

Divide the total wattage required (from step 1, above) by the battery voltage (12) to determine the DC amps required.

•STEP 3: Estimate Battery Amp-Hours Required (for operation unsupported by the alternator)

Multiply the DC amps required (from step 2, above) by the number of hours you estimate you will operate your equipment exclusively from battery power before you have to recharge your batteries. Compensate for inefficiency and wiring losses by multiplying this number by 1.2. This will give you a rough estimate of how many amp-hours of battery power (from one or several batteries) you should connect to your Inverter.

NOTE: Battery amp-hour ratings are usually given for a 20-hour discharge rate. Actual amp-hour capacities are less when batteries are discharged at faster rates. For example, batteries discharged in 55 minutes provide only 50% of their listed amp-hour ratings, while batteries discharged in 9 minutes provide as little as 30% of their amp-hour ratings.

540 watts ÷ 12V = 45 DC Amps

45 DC Amps × 5 Hrs. Runtime

× 1.2 = 270 Amp-Hours

You must allow your batteries to recharge long enough to replace the charge lost during Inverter operation or else you will eventually run down your batteries.

NOTE: For Tripp Lite Inverters over 1000 watts used in mobile applications, Tripp Lite recommends you use at least two batteries, if possible, fed by a heavy-duty alternator anytime the vehicle is running. Tripp Lite Inverters will provide adequate power for ordinary usage within limited times without the assistance of your vehicle’s alternator. However, when operating extremely heavy electrical loads at their peak, you may wish to “assist your batteries” by running your vehicle engine faster than normal idling.

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