Configuring The Bat Tery Bank - Wagan Tech 2294 Manual De Usuario

Slim Line Power Inverters by Wagan Tech
™
Do not exceed the surge rating of this inverter. This can cause immediate
overload shut down.
At maximum continuous output, this inverter requires a DC power supply (battery
bank) that can continuously supply required amps at 12V DC for the duration of
the run time.
CONFIGURING THE BAT TERY BANK
To determine the minimum battery ampere-hour rating that you will need to
operate appliances from the inverter, and any DC appliances powered by the
battery bank, follow these steps:
1. List the maximum continuous wattage that the inverter has to supply.
2. Estimate the number of hours the appliances will be in use between
battery recharges. This will vary depending on appliances.
For example, a typical home-use coffee maker draws 500 watts during its
brew time of 5 minutes, but it only requires 100 watts thereafter to maintain
the temperature of the pot. Similarly, a typical use of a microwave oven is
only for a few minutes. Some longer operating time appliances are lamps,
TV's, computers, and refrigerator/freezers.
3. Determine the total watt-hours of energy needed. This is done by
multiplying average power consumption in watts by hours of run time. For
example: 1,000 watts for 10 hours = 10,000 watt hours.
To get an estimate of the maximum current (in amps) that a battery bank must be
capable of delivering to the inverter, divide the load watts by 10. For example a
1,000 watt appliance load will need 100 amps at 12 Volts DC.
Using the 1,000 watts (or 150 Amps) for 10 hours example as above, then 100
amps is needed for 10 hours. This provides us with the basic amp-hours (AH) of
battery that is required. Ten hours at 100 amps equals 1,000 Amp Hours (AH).
This answer is just a beginning of configuring the battery bank because there
are additional factors that determine actual run time. These include:
• AC appliance load and time in use (basic AH)
• Cable gage and length (cable losses)
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• Charge level of the batteries (between use, chargers have to be able to
fully charge the batteries)
• Temperature of the batteries (colder batteries provide fewer amps)
• Age and condition of the batteries (older batteries lose AH capacity)
• Compliance with turning off unnecessary AC loads
• Use of DC appliances and compliance with turning off unnecessary DC
loads
• If the inverter is installed in a vehicle and the alternator output in Amps
cannot supply enough current for the inverter, additional batteries are
required to supply the required current.
DERATING THE BAT TERY BANK
Most lead-acid batteries have a rating expressed in amp-hours (AH). The
most common rating of AH is at the "20-hour rate".
NOTE: Despite several Internet explanations, here is no relationship
between Cold Cranking Amps (CCA) and Ampere Hours (AH).
For example, if a 20Ah battery is discharged at an 1 amp rate, is will take 20
hours to discharge that battery. The terms "charged" and "discharged" relate to
actual battery voltage. This means that the output voltage of a nominal 12 volt
battery starts at 13.2 volts (fully charged) then drops to 10.6 volts (discharged).
If the load on the battery causes the battery to discharge faster than the 20 hour
rate, the capacity (AH) of the battery is measurably reduced (derated). Derating
is a major run time factor. Some benchmarks are as follows:
• If an 100 Ah Battery is discharged at 100 Amps, the battery capacity acts
like a 56 Ah battery.
• If an 100 Ah Battery is discharged at 200 Amps, the battery capacity acts
like a 32 Ah battery.
Again, both high discharge rates are faster than the 20-hour rate so battery
capacity seems lower.
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