Battery Wire Size per Voltage, Amperage Load and Length
Chart below shows Minimum cable size to use (AWG wire)
Fine Stranded Stereo wire makes great battery cable giving the best gage wire for proper battery charge. The fine stranded wire will pass more amperage than course stranded wire that has a lower "strand count". When building your battery wiring harness be sure to use top quality battery terminals. Following your diagram wiring for the battery alternator relationship. Your alternator works with your battery so the alternator wiring to the battery is very important to maintain top alternator amp wire load, this is important with 12v battery setups as well as 24v battery systems. All systems are a failure without proper grounding through the ground wire, Proper grounding of your vehicle is important to all electrical equipment in the vehicle.
System
Voltage
Amps < 5 Ft 5-10 Ft 10-15 Ft 15-20 Ft 20-25 Ft 25-30 Ft
12 Volt 0-60 8 AWG wire 4 AWGwire 2 AWG wire 2 AWG wire 1 AWG wire 2/0 AWG wire
12 Volt 60-100 6 AWG 4 AWG 1 AWG 0 AWG 0 AWG 2/0 AWG
12 Volt 100-150 4 AWG 2 AWG 0 AWG 2/0 AWG 2/0 AWG 3/0 AWG
12 Volt 150-190 4 AWG 1 AWG 2/0 AWG 3/0 AWG 4/0 AWG 4/0 AWG
12 Volt 190-250 2 AWG 0 AWG 2/0 AWG 4/0 AWG 4/0 AWG 4/0 AWG
12 Volt 250-300 0 AWG 2/0 AWG 3/0 AWG 4/0 AWG 4/0 AWG 4/0 AWG
24 Volt 0-30 14 AWG wire 14 AWG wire 10 AWG wire 8 AWG wire 8 AWG wire 6 AWG wire
24 Volt 30-50 12 AWG 10 AWG 8 AWG 6 AWG 6 AWG 4 AWG
24 Volt 50-75 10 AWG 8 AWG 6 AWG 4 AWG 4 AWG 2 AWG
24 Volt 75-100 6 AWG 6 AWG 4 AWG 4 AWG 2 AWG 1 AWG
24 Volt 100-125 4 AWG 4 AWG 4 AWG 2 AWG 2 AWG 1 AWG
24 Volt 125-150 2 AWG 2 AWG 1 AWG 1 AWG 0 AWG 0 AWG