8R
Battery Selection
540 watts ÷ 12V =
45 DC Amps
270 Amp-Hours ÷ 55 Amps
Inverter/Charger Rating =
5 Hours Recharge
Select Auxiliary Battery Type
(if any)
Select “Deep Cycle” batteries to receive optimum performance from your Inverter/Charger. Do not use ordinary car or starting batteries or batteries
rated in Cold Cranking Amps (CCA). If the batteries you connect to the Inverter/Charger are not true Deep Cycle batteries, their operational life-
times may be significantly shortened. If you are using the same battery bank to power the Inverter/Charger as well as DC loads, your battery bank
will need to be appropriately sized (larger loads will require a battery bank with a larger amp-hour capacity) or the operational lifetimes of the bat-
teries may be significantly shortened.
Batteries of either Wet-Cell (vented) or Gel-Cell /Absorbed Glass Mat (sealed) construction are ideal. 6-volt “golf cart”, Marine Deep-Cycle
or 8D Deep-Cycle batteries are also acceptable. You must set the Inverter/Charger’s Battery Type DIP Switch (see Configuration section
on page 6 for more information) to match the type of batteries you connect or your batteries may be degraded or damaged over an extend-
ed period of time. In many cases, the vehicle battery may be the only one installed. Auxiliary batteries must be identical to the vehicle bat-
teries if they are connected to each other.
Match Battery Amp-Hour Capacity to Your Application
Select a battery or system of batteries that will provide your Inverter/Charger with proper DC voltage and an adequate amp-hour capacity to
power your application. Even though Tripp Lite Inverter/Chargers 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.
• STEP 1: Determine Total Wattage Required
Add the wattage ratings of all equipment you will connect to your Inverter/Charger.
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/Charger will operate at higher efficiencies at about 75% - 80% of nameplate rating.
• 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 with utility- or generator-supplied
AC power. Compensate for inefficiency 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/Charger.
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.
• STEP 4: Estimate Battery Recharge Required, Given Your Application
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.
To estimate the minimum amount of time you need to recharge your batteries
given your application, divide your required battery amp-hours (from step 3,
above) by your Inverter/Charger’s rated charging amps (see Specifications section).
NOTE! For Tripp Lite Inverter/Chargers providing 1000 watts or less of continuous AC power, a full-size battery
will normally allow sufficient power for many applications before recharging is necessary. For mobile applications,
if a single battery is continuously fed by an alternator at high idle or faster, then recharging from utility or generator
power may not be necessary. For Tripp Lite Inverter/Chargers 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 Inverter/Chargers will provide adequate power for ordinary usage within limited times without the
assistance of utility or generator power. However, when operating extremely heavy electrical loads at their peak
in the absence of utility power, you may wish to “assist your batteries” by running an auxiliary generator or vehicle
engine, and doing so at faster than normal idling.
Example
Tools
300W + 220W + 20W =
540W
¼" Drill
Orbital Sander
Cordless Tool Charger
Appliances
300W + 140W + 100W =
540W
Blender
Color TV
Laptop Computer
45 DC Amps × 5 Hrs. Runtime
× 1.2 Inefficiency Rating =
270 Amp-Hours
