ft ordered
#2 6 18" half red [54" c three pre splitter]
#6 50 ft
#8 25ft
#10 check inv
#12 50 ft
Chart: Voltage Drop 2%
Maximum one-way distance, in feet of two conductor copper wire
for 2% voltage loss in 12 volt systems. Wire Size (AWG)
May double distance if 4% loss is ok.
Never exceed 2% drop for wire connecting PV modules and batteries.
Usually 4-5% loss ok for connecting batteries and lighting circuits.
Multiply distances by 2 for 24 volts and by 4 for 48 volts.
| 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 |
11.5 |
22.5 |
35.5 |
57 |
90 |
145 |
180 |
290 |
| 10 |
4.5 |
7 |
11.5 |
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 |
. |
. |
. |
. |
. |
. |
3.6 |
5.8 |
7.3 |
11 |
20ft Cargo calculations:
Max #2 is 1Way dist36" , 3.6 ft, so @100a 2% Max both Dir. 7.2 ft [My#2 Application 4.5ft to 6 ft]
Max #2 is 1Way dist36" , 4.2 ft, so @100a , 4% Max both Dir. 8.5 ft
Max #2 is 1Way dist 7.2.5 ft, so @50a , 2% Max both Dir. 14.5 ft
Max #2 is 1Way dist 8.5ft, so @50a , 4% Max both Dir. 17 ft
Max #2 is 1Way dist 4.5 ft, so @40a , 2% Max both Dir. 9 ft
Max #2 is 1Way dist 10.5ft, so @40a , 4% Max both Dir. 21 ft
Max #6 is 1Way dist 7.25 ft, so @20a , 2% Max both Dir. 14.5 ft
Max #6 is 1Way dist 17 ft, so @20a , 4% Max both Dir. 34 ft
Max #6 is 1Way dist 5.75 ft, so @25a , 2% Max both Dir. 11.5 ft
Max #6 is 1Way dist 13.5 ft, so @25a , 4% Max both Dir. 27 ft
Max #6 is 1Way dist 4.75 ft, so @30a , 2% Max both Dir. 9.5 ft
Max #6 is 1Way dist 11.5 ft, so @30a , 4% Max both Dir. 23 ft
Max #8 is 1Way dist 3.5 ft, so @25a , 2% Max both Dir. 7 ft
Max #8 is 1Way dist 8.5 ft, so @25a , 4% Max both Dir. 17 ft
Max #8 is 1Way dist 6 ft, so @15a , 2% Max both Dir. 12 ft
Max #8 is 1Way dist 14 ft, so @15a , 4% Max both Dir. 28 ft
Max #8 is 1Way dist 11.25 ft, so @8a , 2% Max both Dir. 22.5 ft
Max #8 is 1Way dist 27.5 ft, so @8a , 4% Max both Dir. 53 ft
Max #8 is 1Way dist 15 ft, so @6a , 2% Max both Dir. 30 ft
Max #8 is 1Way dist 35.75 ft, so @6a , 4% Max both Dir. 71 ft
Max #10 is 1Way dist ft, so @50a , 2% Max both Dir. 2.3 ft
Max #10 is 1Way dist ft, so @40a , 2% Max both Dir. 2.8 ft
Max #10 is 1Way dist 1.75 ft, so @30a , 2% Max both Dir. 3.5 ft
Max #10 is 1Way dist 4.5 ft, so @30a , 4% Max both Dir. 9 ft
Max #10 is 1Way dist 2.75 ft, so @20a , 2% Max both Dir. 5.5 ft
Max #10 is 1Way dist 6.5 ft, so @20a , 4% Max both Dir. 13 ft
Max #10 is 1Way dist 5.75 ft, so @10a , 2% Max both Dir. 11.5 ft
Max #10 is 1Way dist 13.5 ft, so @10a , 4% Max both Dir. 27 ft
Max #10 is 1Way dist 5.75 ft, so @8a , 2% Max both Dir. 11.5 ft
Max #10 is 1Way dist 17 ft, so @8a , 4% Max both Dir. 34 ft
Max #10 is 1Way dist 8.75 ft, so @6a , 2% Max both Dir. 17.5 ft
Max #10 is 1Way dist 22.5 ft, so @6a , 4% Max both Dir. 45 ft
Max #12 is 1Way dist 1.75 ft, so @20a , 2% Max both Dir. 3.5 ft
Max #12 is 1Way dist 4 ft, so @20a , 4% Max both Dir. 8 ft
Max #12 is 1Way dist 3.5 ft, so @10a , 2% Max both Dir. 7 ft
Max #12 is 1Way dist 8.5 ft, so @10a , 4% Max both Dir. 17 ft
Max #12 is 1Way dist 4.25 ft, so @8a , 2% Max both Dir. 8.5 ft
Max #12 is 1Way dist 10.5 ft, so @8a , 4% Max both Dir. 21 ft
Max #12 is 1Way dist 6 ft, so @6a , 2% Max both Dir. 12 ft
Max #12 is 1Way dist 14 ft, so @6a , 4% Max both Dir. 28 ft
Max #14 is 1Way dist 1.5 ft, so @15a , 2% Max both Dir. 3 ft
Max #14 is 1Way dist 3.5 ft, so @15a , 4% Max both Dir. 7 ft
Max #14 is 1Way dist 2.25 ft, so @10a , 2% Max both Dir. 4.5 ft
Max #14 is 1Way dist 6.5 ft, so @10a , 4% Max both Dir. 11 ft
Max #14 is 1Way dist 2.75 ft, so @8a , 2% Max both Dir. 5.5 ft
Max #14 is 1Way dist 6.5 ft, so @8a , 4% Max both Dir. 13 ft
Max #14 is 1Way dist 3.75 ft, so @6a , 2% Max both Dir. 7.5 ft
Max #14 is 1Way dist 9 ft, so @6a , 4% Max both Dir. 18 ft
Max #14 is 1Way dist 5 ft, so @4a , 2% Max both Dir. 10 ft
Max #14 is 1Way dist 13.5 ft, so @4a , 4% Max both Dir. 27 ft
Max #14 is 1Way dist 11.25 ft, so @2a , 2% Max both Dir. 22.5 ft
Max #14 is 1Way dist 26.5 ft, so @2a , 4% Max both Dir. 53 ft
Max #14 is 1Way dist 22.5 ft, so @1a , 2% Max both Dir. 45 ft
Max #14 is 1Way dist 53 ft, so @1a , 4% Max both Dir. 106 ft
100 Watt '12 volt' panel max 8.33 amps. [Actual 5.5a x 6hr/day= Total 33ah/d ]
2% PV to Batt,
max 1 way distance is:
14g=5ft , 12g=8ft or 17ft 2 strands , 10g=11ft ,8g=22ft , 6g=35ft
75 Watt '12 volt' panel max 6.25 amps. [Actual 4.4a x 6hr/day= Total 26.4ah/d ]
2% PV to Batt,
max 1 way distance is:
14g=7ft , 12g=11.5ft , 10g=17ft ,8g=30ft , 6g=47ft
50 Watt '12 volt' panel max 4.16 amps. [Actual 2.75a x 6hr/day= Total 16.5ah/d ]
2% PV to Batt,
max 1 way distance is:
14g=9.5ft , 12g=17ft , 10g=27ft ,8g=44.5ft , 6g=72ft
12 volt Wiring Size Selection can Achieve Acceptable Performance
1. Correct wire size & type improve system performance,reliability and efficiency.
2. Wire size must carry maximum current used with minimium desired or acceptable voltage loss
3. Wire has resistance to current flow , causing a voltage drop from power source to load, decreasing efficiency of power source in low voltage systems.
4. Select Wire type by how and where it will be used to withstand the worst conditions. [sunlight exposure] , [high temperatures] , [direct burial].
5. The goal of wire sizing guides give minimum wire size needed to limit voltage drops to 5% at those distances in a 12V/24V systems.
6. To limit losses to 2% , divide distance by 2.5.
7. For 48V system multiply distance from 24V chart by 2.
Maximum Allowable ampacities of conductors (wires) in conduit, raceway, cable or directly buried, based on ambient temperature of 86° F (30° C).
NEC specifies overcurrent protection device not exceed 30A for 10 AGW wire, 20A for 12 AGW wire and 15A for 14 AWG wire.
NEC allows rounding up cable ampacity to the next size standard fuse or breaker.
Remember, many system designers have a knowledge deficit of the oft serious implications of voltage drop and wire size. AC circuits last infinitely. DC are often very limited. Do your own math!
[120/240VAC] Conventional volts ac circuits , wire is sized to safe amperage carrying capacity (ampacity). Biggest concern is fire hazards.
[12, 24, 48VDC] Offgrid, mobile or backup low voltage systems Biggest concern is power loss.
Avoid Sizing by ampacity as the main criteria, larger give more tolerance to voltage drop. The shorter the run the more tolerance.
Remember 12v vs 120v equals 10 times power loss for a single volt.
|
LiFePO4 State Of Charge, Voltage Chart
Maximum Ampacity
| Wire Size |
Copper |
Aluminum |
| 167° F (75° C) |
194° F (90° C) |
167° F (75° C) |
194° F (90° C) |
| *14 |
20 |
25 |
|
. |
| *12 |
25 |
30 |
20 |
25 |
| *10 |
35 |
40 |
30 |
35 |
| 8 |
50 |
55 |
40 |
45 |
| 6 |
65 |
75 |
50 |
60 |
| 4 |
85 |
95 |
65 |
75 |
| 2 |
115 |
130 |
90 |
100 |
| 1 |
130 |
150 |
100 |
115 |
| 1/0 |
150 |
170 |
120 |
135 |
| 2/0 |
175 |
195 |
135 |
150 |
| 3/0 |
200 |
225 |
155 |
175 |
| 4/0 |
230 |
260 |
180 |
205 |
| |
