Which Battery Is Best For Trolling Motor Use?

Lithium-ion batteries, particularly LiFePO4 (lithium iron phosphate), are optimal for trolling motors due to their high energy density (100–150 Wh/kg), lightweight design (50% lighter than lead-acid), and 2,000–5,000 cycle lifespans. A 24V or 36V system with 50–100Ah capacity balances runtime and thrust for freshwater/saltwater use. Key factors include waterproof casing, marine-grade terminals, and compatibility with PWM controllers. AGM batteries remain a budget option but require frequent charging to avoid sulfation.

RG72105P Product

Why choose deep-cycle over starting batteries for trolling motors?

Deep-cycle batteries provide sustained low-current discharge (20–50A), essential for trolling motors running 4–8 hours. Starting batteries, designed for short high-current bursts, degrade rapidly if cycled below 50% depth of discharge (DoD). Pro Tip: Look for “marine deep-cycle” labels with reserve capacity (RC) ≥120 minutes for stable performance.

Deep-cycle batteries use thicker lead plates (2.5–3mm vs. 1.5mm in starters) to endure 50–80% DoD daily. For example, a 24V 100Ah LiFePO4 pack delivers 2.4kWh, powering a 55 lb-thrust motor for ~6 hours at medium speed. However, pairing mismatched batteries in series can cause imbalance—always use identical units. Transitionally, while AGM batteries tolerate vibrations better, lithium models excel in weight-sensitive applications like kayaks. Did you know a 30Ah lithium battery often outlasts a 50Ah AGM due to higher usable capacity?

What voltage (12V, 24V, 36V) suits different trolling motor thrusts?

Higher voltage systems reduce current draw, minimizing heat and voltage drop. 12V motors (30–55 lbs thrust) work for small boats, while 24V (55–80 lbs) and 36V (80+ lbs) handle larger vessels. Pro Tip: Never mix 12V/24V batteries in series—cell mismatch risks overheating.

A 36V 112Ah lithium battery (4.03kWh) can run an 80 lb-thrust motor at 50% load for ~8 hours. Practically speaking, voltage selection depends on boat size and runtime needs. For instance, saltwater anglers targeting 10+ hours often opt for 36V systems. Transitionally, higher voltage requires compatible chargers—check if your onboard charger supports multi-bank charging. But what happens if you use 12V for a 24V motor? Expect 50% speed loss and potential controller damage.

Lithium vs. lead-acid: Which chemistry dominates trolling applications?

Lithium batteries outperform lead-acid in energy density, weight, and lifespan. A 36V 60Ah LiFePO4 (7.2kg) replaces a 36V 100Ah AGM (30kg), saving 76% weight. However, lithium costs 2–3x upfront but lasts 5x longer. Pro Tip: Use lithium in temperatures above -10°C to prevent BMS shutdowns.

Lead-acid remains viable for cold climates (down to -20°C) and budget builds. For example, a 12V 100Ah AGM ($200) suits occasional users, while a 24V 50Ah LiFePO4 ($600) better serves daily anglers. Transitionally, lithium’s flat discharge curve maintains motor speed until 10% capacity, whereas AGM voltage sags reduce thrust by 30% at 50% DoD. Did you know lithium batteries charge 3x faster, minimizing downtime between trips?

How to calculate trolling motor runtime accurately?

Runtime (hours) = (Battery Ah × Voltage × 0.85) / Motor Wattage. For a 36V 100Ah battery powering a 1,500W motor: (100 × 36 × 0.85)/1500 ≈ 2 hours. Pro Tip: Derate capacity by 15% to account for inefficiencies.

Actual runtime varies with propeller load, wind, and current. For example, a 55 lb-thrust motor drawing 42A at 12V consumes 504W (12V×42A). A 100Ah AGM provides 50Ah usable (50/42≈1.2 hours). Transitionally, lithium’s 90% usable capacity extends this to 90Ah (90/42≈2.1 hours). But how does battery age affect this? After 300 cycles, AGM capacity drops to 70%, reducing runtime to 0.8 hours—lithium retains 80% after 2,000 cycles.

Fasta Power Expert Insight

FAQs

RG72180 Product