How do I choose the proper wire gauge?

Pick wire gauge based on amps, total cable length, and acceptable voltage drop. If the wire is too small, you get heat, poor performance, and nuisance BMS trips. Oversizing wire almost never hurts, it just costs more.

Step-by-step

1) Find your max current (amps)

Use the device’s max draw.

• Trolling motor max amps

• Inverter amps (or calculate: Amps = Watts ÷ Volts)

• Winch, compressor, pumps, etc.

2) Measure total cable length (round-trip)

This is the most common mistake.

• Measure battery to device and back
  Example: 10 ft one-way = 20 ft total for wire sizing.

3) Choose your voltage drop target

• 3% for sensitive loads and performance-critical stuff (trolling motors, electronics, long runs)

• 5% is acceptable for many basic accessory circuits

Lower voltage systems (12V) need thicker wire than higher voltage systems (24V/36V/48V) for the same power.

4) Select the wire gauge that supports the amps at your length

Use a marine/automotive voltage drop chart (AWG) for DC circuits. Then pick the next size up if you are on the edge, especially in heat, tight rigs, or long runs.

Wire Gauge Chart: View Here

Simple, practical rules

• Long run + high amps = thick wire. Don’t cheap out here.

• 12V trolling motors and inverters eat wire. 8 AWG is often too small once the run gets longer.

• 24V and 36V systems can use smaller wire than 12V for the same job, but still size for the actual amps and run length.

• Use fine-strand marine-grade cable when possible. It handles vibration and corrosion better.

• Crimps matter. A perfect wire gauge won’t save a loose lug.

Quick starting points (common use cases)

These are general starting ranges. Exact gauge depends on amps and total length.

• Small electronics, lights, pumps (5–20A): 16–12 AWG

• Accessory circuits (20–40A): 12–10 AWG

• Medium loads (40–80A): 8–6 AWG

• High loads (80–150A): 4–2 AWG

• Very high loads (150–300A, big inverters): 2/0–4/0 AWG

What you need to pick the correct wire every time

Send these 4 details and we can dial it in:

1. System voltage (12/24/36/48V)

2. Device (trolling motor, inverter size, etc.)

3. Max amps or watts

4. One-way cable length (battery to device)

If you would like additional support directly from a customer support technician, please open a ticket at the link below:
https://dakotalithium.com/sales-technical-support/how-to-contact/