1. Size the motor first
Motor current × hours of use = Ah for the session. A 24V motor drawing 40A for 4 hours needs about 160Ah; a 24V 200Ah covers it with reserve for electronics.
Marine loads are bursty: a trolling motor pulls hard for hours, a bilge pump kicks in without warning, and everything lives in a damp, vibrating space.
For a 12V trolling motor, a single 100Ah pack is the lightest option. For a 24V motor, use a native 24V pack or two 12V packs in series — but never put 24V packs in series. IP65 protects against spray, not immersion.
Sizing rule: daily Wh first, then autonomy, then the model.
The arithmetic is simple; the mistakes come from using running watts instead of surge, or Ah without the voltage.
Motor current × hours of use = Ah for the session. A 24V motor drawing 40A for 4 hours needs about 160Ah; a 24V 200Ah covers it with reserve for electronics.
Add the fish finder, lights and radio for the day, then keep 20–30% in reserve so you are not running the pack to cutoff offshore.
The 24V 100Ah and 200Ah packs are rated 100A continuous. A 24V trolling motor typically draws well under that; a bow thruster may not. Check the surge and duty cycle before using the pack for thrusters.
Example: 24V trolling motor at 40A for 4 hours = 160Ah; plus 20Ah for electronics = 180Ah. One 24V 200Ah (200Ah, 5,120Wh) covers the day with reserve. Two 24V 100Ah in parallel is the other option.
Assumes 80% depth of discharge and 85% inverter efficiency. Cold weather, ageing and higher inverter losses need extra margin.
Start with the smallest pack that covers the load, then check the bay and the inverter surge.
The everyday 12V pack. Light enough to swap by hand, with 100 A continuous output and 4S4P expansion.
Best for: Weekend RVs, camper vans, 12V fridges, small boat electronics.
Bank limit: 4S4P
A native 25.6 V pack: half the current of a 12V pack at the same power, fewer inter-battery links.
Best for: Native 24V boats, trolling motors and small off-grid systems.
Bank limit: 1S4P
The largest pack we list today: 5.1 kWh in one 24V case, parallel up to 1S4P.
Best for: Home backup, larger 24V house banks, multi-day off-grid loads.
Bank limit: 1S4P
Not sure? Use the sizing calculator, or send us the load list and we will check it.
Include the application, daily runtime, inverter size and destination market. We will reply with a model recommendation and the matching datasheet.