BATTERIES

To achieve 50% cycling you should calculate your Amp-hour consumption between charging cycles and use a battery bank with twice that capacity**. Each AC appliance or tool has a rating plate on it and will be rated in either AC Amps or Watts or AC VA (Volt-Amps) apparent power. To calculate Amp- hour consumption, use one of the formulas to the right to calculate the DC Amp-hour draw for a 12 volt system.

Calculate the Amp-hours for every AC appliance or tool that will be operated on the inverter. This will provide the total number of Amp-hours used between recharges. Size the battery bank using this number as a guideline. A good rule to follow is to size the battery bank a minimum of 2 times larger than the

total Amp-hour load requirement. Plan on recharging when 50% discharged.

AMP-HOUR CONSUMPTION FORMULAS

(AC Amps x 10) x 1.1 x hours of operation = DC Amp-hours

(Watts/ DC Voltage) x 1.1 x hours of operation = DC Amp-hours

(AC VA/ DC Voltage) x 1.1 x hours of operation = DC Amp-hours

DC Voltage is 12, 24 or 32 depending on

your system.

In all formulas, 1.1 is the correction factor for

inverter efficiency.

Typical Power Consumptlon

The chart identifies typical power consumption for common AC loads. Use it as a guide when identifying your power requirements.

**Batteries are typically charged to 85% of full charge when charging with alternators without 3-stage regulators.

Typical Power Consumption

 

Typical

 

 

Appliance Run Times / Amp Hours

 

 

Appliance

 

 

 

 

 

 

 

 

Wattage

 

 

 

 

 

 

 

 

 

5 Min.

15 Min.

30 Min.

1 Hr.

2 Hr.

3 Hr.

8 Hr.

24 Hr.

 

 

 

13" Color TV

50

 

.33

1

2

4

8

12

32

96

 

 

 

 

 

 

 

 

 

 

 

19" Color TV

100

 

.66

2

4

8

16

24

64

192

 

 

 

 

 

 

 

 

 

 

 

VCR

50

 

.33

1

2

4

8

12

32

96

 

 

 

 

 

 

 

 

 

 

 

Lamp

100

 

.66

2

4

8

16

24

64

192

 

 

 

 

 

 

 

 

 

 

 

Blender

300

 

2

6

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Laptop Computer

50

 

.33

1

2

4

8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Curling Iron

50

 

.33

1

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3/8 Power Drill

500

 

3.3

10

20

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Icemaker*

200

 

 

 

2.6

5.2

10.4

15.6

41.6

83.2

 

 

 

 

 

 

 

 

 

 

 

Coffee Maker

1000

 

6.6

20

40

80

160

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3 cu' Refrigerator*

150

 

 

 

2

4

8

12

32

96

 

 

 

 

 

 

 

 

 

 

 

20 cu' Refrigerator*

750

 

 

 

21

42

84

126

336

672

 

 

 

 

 

 

 

 

 

 

 

Compact Microwave

750

 

5

15

30

60

120

180

 

 

 

 

 

 

 

 

 

 

 

 

 

Full Size Microwave

1500

 

10

30

60

120

240

360

 

 

 

 

 

 

 

 

 

 

 

 

 

Vacuum

1100

 

7.3

22

44

88

176

264

 

 

 

 

 

 

 

 

 

 

 

 

 

Number in each box represents the total Amp hours used (@ 12 volt DC) based on various continuous run times.

*Note refrigeration is typically calculated using a 1/3-duty cyle.

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Many electric motors have momentary starting require- ments well above their opera- tional rating. Start up watts are listed where appropriate. Individual styles and brands of appliances may vary.

If using the same battery bank for the inverter and other DC loads, be sure to consider the power consumption of the DC loads when sizing the battery bank.

NOTE Certain laser printers, breadmakers, digital clocks and appliance/tool chargers may not operate on modified sine wave.

Part No. 90-0123-00 Libertycombi.p65 10/26/98

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Thomas & Betts 20D, 15D owner manual AMP-HOUR Consumption Formulas, Typical Power Consumptlon