Making sense of an independently battery powered home.
The key to becoming your own Power Producer is to understand how a battery power system operates.
Before getting started, it is important the design of any battery power system meets or exceeds the requirements of the (NEC) National Electrical Code, State and local building Codes to ensure a safe building and battery power system.
Employ a professional licensed electrician that has experience with battery powered homes.
Understanding the Power Sources.
Their are two major components to a battery bank system, 1. Battery charging power, 2. 120 VAC power inverter, power inverter converts 12-volt, 24-volt or 48-volt DC battery power to 120 VAC standard household power.
Modified sine wave inverters are not capable of providing the power to operate some motors, electronics or electrical appliances. To overcome this problem, a true sine wave inverter must be used.
Efficiency of inverters and the power loss in wiring, it takes approximately 10 to 12 amps of 12-volt DC power to produce 1 amp of 120 VAC power. Always calculate the highest load with appliances, be sure to add the start surge power of up to five times the current with large inductive starting loads. Always keep batteries at a full state of charge.
Large or small power inverters must have a circuit breaker or a fuse on the positive wire between the battery and the power inverter.
Large power inverter must be grounded and only connected directly to the battery bank. Never operate a large power inverter off building wiring. It is important to use circuit breaker or a fuse rated for the component/appliance on the positive wire before plugging into the receptacle of building.
DANGER: Never use cigarette lighter plugs/cigarette lighter receptacles in any building wiring system. From experience, they are dangerous and can cause fires. Use (NEC) National Electrical Code, approved 20 amp 240 VAC plugs and 240 VAC duplex receptacles they are approved for 12-volt DC or 24-volt DC battery powered homes, cabins or battery power back-up systems and they fit in standard wiring boxes.
Example: Flooded lead acid battery, a 100 amp-hour battery has 1 amp available for 100 hours and only 40% should be used then that would be 40 hours available, if the battery bank is a 1000 amp-hour battery bank it has 1 amp available for 1000 hours and only 40% should be used then that would be 400 hours available. These facts are to be on the safe side when there is a need for extra power. An oversized battery bank is always better then an undersized battery bank.
Keep in mind; just because there are 1000 amp-hours in the battery bank, do not allow batteries to go below a 60% state of charge for flooded lead acid batteries and 70% state of charge for gel cells batteries. In reality, only 40% of amps should be used for flooded lead acid and 30% of amps for gel cell batteries for optimum battery life and performance.
1. Determine the number and amps of energy efficient appliances that are going to be used. 2. Determine how many hours per day the battery bank system will be used. 3. Then, determine the total battery bank amp-hour capacity needed for one to two weeks of power.
Example: A 120 VAC fan uses 5 amps at 120 VAC calculate 5 amps x 120 VAC = 600 watts hour, 600 watt hours in 12-volt DC power this would be 600 watts 120 VAC divided by 12-volt DC = 50 amps of 12-volt DC power per hour consumption. Keep in mind; depending on the power inverter, it takes approximately 10 to 12 amps of 12-volt DC power to produce 1 amp of 120 VAC power.
A battery bank system operating without one large power inverter for the whole house is more efficient than one operating with one large power inverter. Appliances rated for 12-volt or 24-volt DC will give you energy efficient Compact Fluorescent bulbs, 12-volt or 24-volt DC, Refrigerator/Freezer, 24-volt or 48-volt DC Air Conditioner, 12-volt or 24-volt DC Ceiling fans/oscillating fans, Laptops computer, 12-volt DC TV/VCR, 12-volt or 24-volt DC Water pressure pumps and power tools etc.
From experience, power inverters are known to say good buy when you need power. At Impact Renewable Energy, we recommend small power inverters to fit the power requirements of a small 120 VAC appliance. By utilizing a small power, inverters to fit the power requirements of each appliance can save you a lot of money and battery bank power. When adding appliances to the battery bank always look for energy efficient appliances. (Check Voltage and Amperage) It is important to manage all electrical loads, even operate the most energy efficient loads wisely for minimum amount of battery power usage.
Always turn off appliances when not in use and it is important to use a switch to disconnect the circuit. Phantom/ghost loads Will Steal your battery's power!
12 VOLT 2% WIRE LOSS CHART
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This wire loss chart is for the maximum distance one-way in feet of various gauge two conductor copper wire from the battery bank to the load for a 2% voltage drop in a 12-volt DC system. A 4 to 5% loss is acceptable between batteries and lighting circuits in most cases. For a 24-volt DC system, multiply the distances by 2. For a 48-volt DC system, multiply the distances by 4.
|
AMPS
|
#14
|
#12
|
#10
|
#8
|
#6
|
#4
|
#2
|
1/0
|
2/0
|
4/0
|
|
1
|
45
|
70
|
115
|
180
|
290
|
456
|
720
|
-
|
-
|
-
|
|
2
|
22.5
|
35
|
57.5
|
90
|
145
|
228
|
360
|
580
|
720
|
1060
|
|
4
|
10
|
17.5
|
27.5
|
45
|
72.5
|
114
|
180
|
290
|
360
|
580
|
|
6
|
7.5
|
12
|
17.5
|
30
|
47.5
|
75
|
120
|
193
|
243
|
380
|
|
8
|
5.5
|
8.5
|
15
|
22.5
|
35.5
|
57
|
90
|
145
|
180
|
290
|
|
10
|
4.5
|
7
|
12
|
18
|
28.5
|
45.5
|
72.5
|
115
|
145
|
230
|
|
15
|
3
|
4.5
|
7
|
12
|
19
|
30
|
48
|
76.5
|
96
|
150
|
|
20
|
2
|
3.5
|
5.5
|
9
|
14.5
|
22.5
|
36
|
57.5
|
72.5
|
116
|
|
25
|
1.8
|
2.8
|
4.5
|
7
|
11.5
|
18
|
29
|
46
|
58
|
92
|
|
30
|
1.5
|
2.4
|
3.5
|
6
|
9.5
|
15
|
24
|
38.5
|
48.5
|
77
|
|
40
|
-
|
-
|
2.8
|
4.5
|
7
|
11.5
|
18
|
29
|
36
|
56
|
|
50
|
-
|
-
|
2.3
|
3.6
|
5.5
|
9
|
14.5
|
23
|
29
|
46
|
|
100
|
-
|
-
|
-
|
-
|
2.9
|
4.6
|
7.2
|
11.5
|
14.5
|
23
|
|
150
|
-
|
-
|
-
|
-
|
-
|
-
|
4.8
|
7.7
|
9.7
|
15
|
|
200
|
-
|
RJR
|
3/09
|
-
|
-
|
-
|
3.6
|
5.8
|
7.3
|
11
|
Design of a Simple Off-Grid battery powered home system or Emergency battery back-up power system.
Coming Soon.
We are available from 9am to 5pm (CST). Monday - Saturday to answer your questions. (210) 409-4646
Disclaimer: At Impact Renewable Energy, we want you to be safe. It is very important to employ a professional licensed electrician. Always ensure that all of your components/appliances are properly fused and grounded for your safety. At Impact Renewable Energy, we strive to provide information and our opinion on this website in good faith. The information and our opinion provided on this website herein is for informational purpose only. There are no warranties, either expressed or implied, regarding the accuracy or completeness of the information provided on this website.
