A 24V trolling motor battery setup is usually either two 12V batteries wired in series or one 24V battery. To choose the right one, confirm your motor’s 24V requirement, pick a battery type (flooded, AGM, or lithium LiFePO4), then size amp-hours based on how long you run and how hard your motor works. Most “24V problems” come from wiring mistakes, voltage drop from undersized cables, or mismatched batteries in the series pair.
24V Selection Table
Use this table as a quick starting point. Your exact needs depend on your motor’s max amps, cable length, boat load, wind/current, and how often you run at high thrust.
| Boat and fishing style | Recommended 24V setup | Target capacity | Why it works | Common mistakes |
|---|---|---|---|---|
| Small boat, calm water, half-day trips | 2×12V deep-cycle AGM or 24V LiFePO4 | 50–100Ah | Enough energy without overbuying | Mixing different 12V batteries; using too thin wire |
| Medium boat, mixed conditions, most days | 2×12V AGM or 24V LiFePO4 | 100Ah | Good balance of runtime and weight | Assuming “100Ah always lasts all day” |
| Heavier boat, windy water, long runs | 24V LiFePO4 preferred | 100–150Ah | Higher usable energy, steadier voltage | Charger mismatch; ignoring low-temp charging limits |
| Weed-heavy flats, high thrust demand | 24V LiFePO4 with strong BMS | 100–200Ah | Handles sustained current better | BMS continuous amps too low; hot connectors |
| Budget build for occasional use | 2×12V flooded deep-cycle | 85–110Ah each | Low upfront cost | Deep discharging flooded batteries repeatedly |
24V Trolling Motor Battery Wiring Mini Diagram
A 24V trolling motor requires a series connection. A parallel connection keeps the voltage the same and only increases capacity.
Correct: 2×12V in series = 24V
To build a 24V system using two 12V batteries, wire it like this:
- Use a short jumper cable to connect Battery A negative (–) to Battery B positive (+).
This jumper is your SERIES LINK. - Connect Motor + to Battery A positive (+).
- Connect Motor – to Battery B negative (–).
✅ This gives you a 24V battery bank.
Wrong for 24V: parallel wiring = still 12V
If you connect positive to positive and negative to negative, that’s a parallel connection.
The bank stays at 12V (you only increase capacity), so it won’t properly power a 24V trolling motor.
Tip: Label the batteries “A” and “B,” and label the jumper cable SERIES LINK so it’s harder to reconnect incorrectly after storage.
What Is a 24V Trolling Motor Battery System
Do you need two 12V batteries for a 24V trolling motor
In most boats, yes. A 24V trolling motor typically runs on a 24V battery bank, which is most commonly made by wiring two 12V batteries in series. Series wiring adds voltage: 12V + 12V = 24V.
Some setups use a single 24V battery instead (often lithium LiFePO4). That can simplify wiring and reduce mismatch issues, but it’s not the only “right” way.
2×12V vs one 24V battery which setup is better
Both can be excellent. Choose based on your priorities:
2×12V series is great when:
- You want more brand choices and easier local replacement.
- You already have two matching 12V batteries.
- You’re using lead-acid (AGM or flooded), where 24V “single batteries” are less common.
One 24V battery is great when:
- You want simpler installation and fewer points of failure.
- You’re going lithium and want built-in balancing/management at the 24V level.
- You want easier charging with a dedicated 24V lithium charger and fewer wiring mistakes.
If you go 2×12V, the two batteries should be the same type, same capacity, same age, and ideally the same model. In a series bank, the weaker battery becomes the bottleneck.
24V Trolling Motor Battery Wiring Series vs Parallel
How to wire two 12V batteries in series for 24V
Series wiring is simple but must be done correctly:
- Connect Battery A negative to Battery B positive with a heavy jumper cable (this is the “series link”).
- Your trolling motor positive goes to the open positive terminal (Battery A positive).
- Your trolling motor negative goes to the open negative terminal (Battery B negative).
That’s it. Don’t connect the motor across the series link. Don’t put the motor leads on the same battery.
Common wiring mistakes that cause low power or shutdowns
These show up constantly in real installs:
- Accidental parallel wiring: the motor “runs” but feels weak because it’s actually on 12V.
- Motor leads on one battery: one battery gets abused, the other barely works.
- Loose lugs or corroded posts: creates resistance, heat, and voltage drop.
- Undersized jumper cable: the series link carries the same current as the main cable; it must be equally robust.
- Mixing battery types or ages: one battery sags first, limiting the whole system.
A quick sanity check: with the bank connected in series and resting, you should measure roughly 25–26V on a full lead-acid bank (surface charge varies) and around 26–27V on a rested 24V LiFePO4 depending on state of charge. Always follow your battery maker’s voltage chart.
How Many Amp Hours Do You Need for a 24V Trolling Motor
Is a 24V 100Ah battery enough for a full day
Sometimes yes, often “it depends,” and that’s why people argue about it online.
A 24V 100Ah battery has about:
- 24V × 100Ah = 2400 watt-hours of energy on paper.
But usable energy depends heavily on chemistry:
- LiFePO4 is commonly used at 80–90% usable for long life → about 1900–2160 Wh usable
- Lead-acid is commonly used at ~50% usable if you want decent cycle life → about 1200 Wh usable
Now compare to real motor draw. Many 24V trolling motors draw single-digit amps at low speeds, but 40–56A (or more) at high thrust depending on model. Average draw across a fishing day is usually far below “max amps,” but wind, current, weeds, and boat weight can push you higher for longer.
A practical, real-world way to think about it:
- If your average draw is around 20–25A, a 24V 100Ah bank can often cover a solid day on lithium and a shorter day on lead-acid.
- If you’re frequently pushing 35–45A average (heavy boat, wind, weeds), 100Ah may feel short, especially with lead-acid.
A simple amp-hour sizing method for 24V setups
You don’t need a perfect calculator to get close.
- Find your motor’s max current (manual/spec plate).
- Estimate your average current based on use:
- Light positioning: 5–15A
- Mixed use: 15–30A
- Hard use (wind/weed/heavy): 25–45A
- Estimate hours of run time you actually need at those loads.
Then use watt-hours:
Usable Wh = Voltage × Ah × Usable %
Runtime hours ≈ Usable Wh ÷ (Voltage × Average amps)
Example using 24V 100Ah:
- LiFePO4 usable: 24 × 100 × 0.85 ≈ 2040 Wh
- Lead-acid usable: 24 × 100 × 0.50 ≈ 1200 Wh
If average draw = 25A:
- LiFePO4 runtime ≈ 2040 ÷ (24 × 25) = 2040 ÷ 600 ≈ 3.4 hours at 25A average
- Lead-acid runtime ≈ 1200 ÷ 600 = 2.0 hours at 25A average
That sounds “short” until you remember: many anglers are not averaging 25A continuously for the entire day. A trolling motor often cycles—short bursts, repositioning, idle drifting, then bursts again. If your true average across the day is closer to 10–15A, those hours increase dramatically.
The takeaway: 100Ah can be enough, but you need to be honest about your conditions and boat load.
Best 24V Trolling Motor Battery Type Flooded AGM or Lithium
AGM vs flooded lead acid for 24V trolling motors
Both are lead-acid deep-cycle, but the ownership experience differs.
Flooded deep-cycle
- Lower upfront cost
- Needs ventilation and basic maintenance habits
- More sensitive to repeated deep discharges and neglect
- Usually heavier for the same usable energy
AGM deep-cycle
- Spill-resistant, lower maintenance
- Better for vibration and enclosed compartments
- Usually better performance under load than flooded
- Still not ideal to deep-discharge regularly if you want long life
If you’re going lead-acid for 24V, AGM is usually the “easy” upgrade if budget allows.
Lithium 24V trolling motor battery what to check before you buy
This is where many buyers get burned: lithium is not just “Ah.” For trolling motors, the key checks are:
- BMS continuous discharge amps: must support your motor’s real-world load.
- Peak/discharge headroom: short spikes during hard acceleration or heavy weeds happen.
- Low-temperature charging rules: most LiFePO4 batteries should not be charged below freezing unless heated.
- Charger compatibility: you need the right voltage profile (more on that later).
- Waterproofing and terminals: marine installs punish weak hardware.
If your lithium battery’s BMS is undersized, you’ll feel it as random cut-outs at higher speed or when the prop loads up.
Lithium 24V Trolling Motor Battery BMS Amps and Voltage Drop
What continuous discharge amps you really need for a 24V trolling motor
Start with your trolling motor’s spec sheet. Many 24V motors in the 70–80 lb thrust range list max currents around 40–56A (model-dependent). Some can be higher in real-world conditions.
A safe selection rule:
- Choose a lithium battery (or 24V bank) whose BMS continuous discharge is at least the motor’s max amps, and ideally 20–50% higher if you fish heavy weeds, strong current, or routinely run high power.
Why the headroom matters:
- Current spikes happen when the prop loads up
- Voltage drop rises under heavy current
- Some BMS units protect aggressively, cutting output quickly
If you’re using two 12V lithium batteries in series, confirm the manufacturer explicitly supports series operation and that both batteries have compatible BMS behavior. A single integrated 24V lithium battery can reduce “two BMS” complexity.
Why voltage drop can feel like a battery problem
Plenty of “battery isn’t strong enough” complaints are actually cable and connection losses.
Signs of voltage drop:
- Motor feels strong at first, then weak under load
- Speed changes more than expected with throttle
- Connectors or lugs get warm or hot
- Breaker trips or electronics reset during high thrust
Practical voltage drop target:
- Aim to keep voltage drop under about 3% on the trolling motor circuit when possible.
- On a 24V system, 3% is roughly 0.7V. That’s not much. Poor cables can eat that quickly.
The fix is usually boring but effective:
- Shorten cable runs where possible
- Use heavier gauge wire for long runs
- Clean and tighten terminals
- Use quality lugs and proper crimping
- Don’t forget the series jumper cable quality
24V Trolling Motor Battery Charger and Charging Rules
What charger do you need for a 24V trolling motor battery
Match the charger to the battery chemistry and to the bank voltage.
For 24V lead-acid (flooded/AGM):
- Use a 24V charger with the correct lead-acid profile
- Temperature compensation is often useful for lead-acid
- Many onboard marine chargers are designed for lead-acid banks
For 24V LiFePO4:
- Use a lithium-compatible 24V charger or a charger with a LiFePO4 mode
- Typical 24V LiFePO4 charge voltage is often in the high-28V range (varies by manufacturer)
- Lithium usually does not need long float charging; some setups prefer a low or disabled float
If you use two 12V batteries in series, the cleanest charging method is usually a dedicated 24V charger for the full 24V bank, assuming the batteries are meant to be series-charged. Some people use two separate 12V chargers (one per battery), but that adds complexity and more failure points.
Can you use a lead acid charger on a 24V lithium battery
Sometimes it “charges,” but it’s risky and not recommended as a default plan.
Why it can go wrong:
- Lead-acid chargers may use a different voltage profile
- Some lead-acid chargers go into desulfation or equalization modes that lithium does not want
- Float behavior may not match what your lithium manufacturer recommends
The safest approach:
- Use a LiFePO4-compatible charger set to the battery maker’s recommended profile.
- If you are forced to use an existing charger temporarily, confirm it has a lithium mode or a programmable profile that meets your battery specifications.
Cold Weather Tips for a 24V Trolling Motor Battery
Low temperature charging limits for lithium
Most LiFePO4 batteries should not be charged at or below freezing unless the battery has a heating function or the cells are warmed above the safe threshold. Discharging in cold is usually allowed, but capacity and voltage performance can drop.
Winter storage state of charge
For off-season storage, lithium and lead-acid have different “happy zones.” Lead-acid generally hates sitting partially discharged. Lithium is more tolerant, but still should be stored in a reasonable state of charge and protected from extreme temperatures.
When self-heating is worth it
If you regularly fish in cold weather and charge on the boat (or in an unheated space), self-heating or a warming strategy can prevent “won’t charge” surprises and protect cycle life.
24V Trolling Motor Battery Setup Recommendations by Use Case
Small boat calm water weekend fishing
- Goal: reliable positioning, modest current draw
- Typical fit: 2×12V AGM or 24V LiFePO4
- Capacity: 50–100Ah (based on how long you run continuously)
Heavier boat windy water long runs
- Goal: sustained thrust, stability under load
- Typical fit: 24V LiFePO4 preferred to reduce weight and increase usable energy
- Capacity: 100–150Ah (or more if you truly run high draw for long periods)
Weed-heavy flats high thrust demand
- Goal: survive prop load and high current spikes
- Typical fit: lithium with strong BMS continuous amps and solid wiring
- Capacity: often 100–200Ah depending on how long you stay in weeds
Budget lead-acid setup vs premium lithium setup
- Budget lead-acid: works, but you’ll get the best life by avoiding deep discharge and charging promptly
- Premium lithium: higher upfront cost, usually more usable energy, lighter weight, steadier voltage, but requires proper BMS and charging compatibility
Troubleshooting a 24V Trolling Motor Battery Bank
Why one battery drains faster in a 24V bank
Most common causes:
- Batteries are mismatched (age, capacity, type, brand, health)
- One battery has a weaker cell or higher internal resistance
- A bad connection forces one battery to work harder
- Charging is uneven or incomplete
- In lithium series setups, one BMS may be behaving differently
Fast checks:
- Measure each battery voltage separately after rest
- Inspect and torque terminals
- Look for heat at connections during operation
- If lead-acid, load test each battery independently
Why the trolling motor cuts out at higher speed
Top causes:
- BMS overcurrent protection or low-voltage protection tripping
- Voltage drop from undersized cables or bad lugs
- Breaker too small or weak breaker overheating
- Prop load in weeds causing sustained high current
Fast checks:
- Feel cables/lugs/breaker for heat
- Inspect series jumper cable gauge and quality
- Confirm motor max amps and compare to BMS continuous rating
- Confirm breaker size matches the motor manufacturer recommendation
24V Trolling Motor Battery Checklist Before You Buy
- Confirm your motor is 24V and verify max current
- Choose your setup: 2×12V series or single 24V
- Pick battery type: flooded, AGM, or LiFePO4
- Set a realistic capacity target: Ah based on conditions, not marketing promises
- Plan wiring: correct series link, short runs, proper gauge, quality lugs
- Add protection: breaker or fuse placed close to the battery bank
- Match charging: correct charger profile for your chemistry
- Plan for cold weather if you fish or charge in winter conditions
If you want a matched 24V LiFePO4 trolling motor battery pack (with the right BMS output, wiring guidance, and charger compatibility), this is where it helps to talk to a supplier who builds for marine loads instead of repurposing generic packs.
FAQ
How many hours will a 24V trolling motor run on a 100Ah battery
A 24V 100Ah battery is about 2400Wh on paper. Usable energy depends on chemistry: many anglers treat lead-acid as ~50% usable for decent life, while LiFePO4 is often used at ~80–90% usable. If your average draw is 10–20A, you can often fish for many hours. If your average draw is 25–45A (heavy wind, weeds, heavy boat), runtime drops fast. The most accurate way is to estimate your average current based on how you fish, then convert to watt-hours as shown in the sizing section.
Is it OK to mix old and new batteries in a 24V trolling motor setup
It’s not a good idea. In a series bank, the weaker battery hits voltage limits first and drags the whole system down. That shows up as shorter runtime, inconsistent thrust, and higher stress on the newer battery. For best results, use two matching batteries (same type, capacity, model, and age) and replace lead-acid batteries as a set.
Do you need a breaker or fuse for a 24V trolling motor battery
Yes, in most installations you should have overcurrent protection. The correct rating depends on your motor’s current draw and manufacturer guidance, but the general best practice is to place a breaker or fuse close to the battery bank to protect the wiring. If you’re unsure, follow the trolling motor manufacturer’s recommended breaker size and use marine-rated components.
Should you choose 24V or 36V for a trolling motor
If your boat is heavier, you fish in wind/current often, or you want stronger performance with less current per watt of power, 36V can be a meaningful upgrade. Higher voltage typically means lower current for the same power, which reduces voltage drop and stress on wiring. But 24V can be more than enough for many boats and is usually cheaper and simpler.
Do you need low-temperature cutoff or self-heating for lithium trolling motor batteries
If you fish or charge in cold environments, low-temperature features matter. Many LiFePO4 batteries restrict charging at or below freezing to protect the cells. A battery with low-temp charge protection prevents damage, and self-heating can be worth it if you regularly need to charge in cold garages, sheds, or on the boat during cold-season trips.
