Solar Powered Trolling Motors And Batteries: The Complete Guide 2025
Last Fourth of July weekend on Lake Buchanan, my trolling motor died 3 miles from the ramp. In 95-degree heat. With no wind. That soul-crushing paddle back taught me two things: always carry a backup paddle (duh), and there had to be a better way to keep my batteries charged on multi-day trips.
Fast forward to today, and I'm running a solar setup that keeps my 24V trolling motor system topped off indefinitely. No more dead battery anxiety, no more cutting trips short, and definitely no more marathon paddling sessions in Texas heat.
Here's the thing about solar powered trolling motor battery systems - they're not as complicated as the forums make them sound, but they're also not as simple as slapping a panel on your kayak and calling it good. After burning through three different setups (and more money than I care to admit), I've figured out what actually works on the water.
Whether you're trying to extend your fishing time, tired of hauling batteries to the charger, or planning that week-long backcountry trip, this guide covers everything from basic solar battery charger for trolling motor setups to complete off-grid systems that'll keep you fishing as long as the fish are biting.
Can You Actually Run a Trolling Motor on Solar Power Alone?
Let me save you some disappointment: No, you can't run a trolling motor directly from solar panels. Trust me, I tried.
Here's why: A typical 55lb thrust trolling motor draws 40-50 amps at full power. Even a massive 300W solar panel only produces about 17 amps in perfect conditions. Do the math, and you're looking at a significant power deficit. Plus, clouds happen, shade happens, and suddenly your "solar-powered" kayak becomes a very expensive paddle boat.
The real magic happens when you use solar panels for trolling motors to charge your batteries while you're fishing, at the dock, or during those long summer days. Think of it as a range extender, not a primary power source.
Understanding Solar Charging for Trolling Motor Batteries
Solar charging isn't rocket science, but getting it right makes the difference between topped-off batteries and a very quiet trolling motor. Here's what actually matters:
How Solar Charging Actually Works?
Your solar panel converts sunlight into DC electricity, which flows through a charge controller (never skip this - I fried a battery learning that lesson) and into your trolling motor battery. The controller prevents overcharging and manages the power flow based on your battery's needs.
On my setup, I see about 5-7 amps of charging current on sunny days - enough to offset several hours of trolling at low speed or completely recharge after a morning of fishing by sunset.
The Reality of Charge Times
Let's talk real numbers. My 100Ah battery needs about 50Ah to recharge from 50% (never discharge below this on lead-acid). With my 100W panel producing 5 amps average:
- Full recharge time: 10 hours of good sunlight
- Daily energy gain: 30-40Ah in summer, 15-20Ah in winter
- Net result: 2-4 extra hours of trolling per sunny day
Not enough to run indefinitely, but plenty to extend multi-day trips significantly. For perspective, check out our guide on charging trolling motor batteries for conventional charging times.
Choosing the Right Solar Panel Size
After testing everything from tiny 20W maintainers to massive 200W panels, here's what actually works:
For Battery Maintenance (Trickle Charging)
10-30W panels: Perfect for keeping a fully charged battery topped off during storage or between weekend trips. I use a 20W panel on my dock that maintains both my trolling batteries year-round.
For Active Charging (Extending Runtime)
50-100W panels: The sweet spot for most kayak setups. My 100W panel fits perfectly across my stern and provides meaningful charging without turning my kayak into a solar barge.
For Serious Off-Grid Use
150W+ panels: If you're planning week-long trips or have a larger boat, go big. My buddy runs a 175W setup on his bass boat that nearly eliminates shore charging during summer.
Panel Type Matters
Monocrystalline panels cost more but deliver 20% better efficiency - crucial when deck space is limited. My Renogy 100W monocrystalline panel outperforms the 120W polycrystalline I started with, despite being smaller.
Battery Types for Solar Charging Systems
Not all batteries play nice with solar. Here's what I've learned the expensive way:
AGM Batteries
My go-to for most setups. They handle the variable charging rates from solar panels well, don't require maintenance, and last 4-5 years with proper care. Currently running Interstate DCM0035 (Group U1) batteries in my kayak.
Lithium (LiFePO4) Batteries
The gold standard if budget allows. They charge faster, weigh half as much, and last 10+ years. My 100Ah LiFePO4 charges completely in 6 hours of good sun versus 10+ for AGM. Just ensure your charge controller has a lithium setting.
Gel Batteries
Good for hot climates but charge slowly - not ideal for solar unless you have massive panels or lots of time.
Flooded Lead-Acid
Cheapest option but requires maintenance and doesn't handle partial charging cycles well. Skip these for solar applications.
For a deep dive on battery options, see our guide on mounting trolling motors on kayaks which covers battery placement and types.
Complete Solar Charging System Setup
Here's exactly how I wire my solar charging system - this setup has worked flawlessly for three seasons:
Basic System Components:
- Solar Panel: 100W monocrystalline (Renogy)
- Charge Controller: 20A MPPT with lithium settings
- Battery: 100Ah LiFePO4
- Wiring: 10AWG marine-grade with MC4 connectors
- Fuses: 15A inline between panel and controller, 30A at battery
Wiring Diagram for 12V System:
Solar Panel (+) → Fuse → Charge Controller Solar (+)
Solar Panel (-) → Charge Controller Solar (-)
Charge Controller Battery (+) → Fuse → Battery (+)
Charge Controller Battery (-) → Battery (-)
Battery (+) → Circuit Breaker → Trolling Motor (+)
Battery (-) → Trolling Motor (-)
Installation Steps:
- Mount the charge controller close to the battery (under 3 feet) in a dry, ventilated spot
- Connect battery to controller FIRST - this initializes the controller properly
- Wire solar panel to controller - use proper MC4 connectors, not wire nuts
- Install inline fuses on positive connections
- Test voltage at each connection point
- Secure all wiring with marine-grade zip ties or conduit
Solar Panels for Different Trolling Motor Voltages
Your trolling motor voltage determines your solar setup complexity:
12V Systems (Most Kayaks)
Simplest setup - one panel, one controller, one battery. My first system used a single 50W panel that extended my fishing time by 3-4 hours per day.
24V Systems (Larger Boats)
Two options:
- Two 12V panels in series: Cheaper but requires matching panels
- Single 24V panel: Cleaner installation but limited options
I run two 100W 12V panels in series for my 24V bass boat setup. Pro tip: use identical panels or power output drops to the lowest panel's level.
36V Systems
Requires three 12V panels in series or specialized equipment. Honestly, at this point, consider a dedicated charging station at the dock - solar panels for trolling boats get unwieldy at 36V.
Real-World Solar Charging Performance
Let me share actual data from my setup over different conditions:
Summer Performance (June-August)
- Sunny days: 40-50Ah daily production
- Partly cloudy: 25-35Ah daily production
- Overcast: 10-15Ah daily production
- Runtime extension: 3-5 hours at medium throttle
Winter Performance (December-February)
- Sunny days: 20-25Ah daily production
- Partly cloudy: 10-15Ah daily production
- Overcast: 3-5Ah daily production
- Runtime extension: 1-2 hours at medium throttle
Factors That Kill Performance:
- Shade: Even partial shade drops output 50-75%
- Panel angle: Flat mounting loses 20-30% versus angled
- Dirty panels: Clean weekly or lose 10-20% output
- Heat: Panels lose efficiency above 77°F (ironic, right?)
Advanced Trolling Motor Battery Charging Setups
For those ready to go beyond basic charging:
Dual Battery with Solar Switching
My current setup uses a battery selector switch:
- Position 1: Trolling motor runs on Battery 1 while Battery 2 charges
- Position 2: Switch when Battery 1 depletes
- Both: Emergency power when needed
This effectively doubles your range while one battery always charges. See our article on kayak modifications for switch mounting ideas.
MPPT vs PWM Controllers
Spent the extra $40 on MPPT - here's why:
- 30% more efficient in real-world conditions
- Better in cloudy weather (extracts power from low light)
- Works with mismatched panel/battery voltages
- Actually cheaper per watt when you factor in efficiency
Smart Monitoring Systems
Installed a Victron BMV-712 battery monitor with Bluetooth. Now I track:
- Real-time solar input
- Battery state of charge
- Time remaining at current draw
- Historical data for optimizing usage
Game-changer for understanding your system's actual performance.
Common Solar Charging Mistakes to Avoid
Learn from my expensive education:
Mistake 1: No Charge Controller
"It's just a small panel, what could go wrong?" Famous last words before cooking a $200 battery. Even 10W panels need controllers.
Mistake 2: Undersized Wiring
10% voltage drop means 10% less charging. Use proper gauge wiring:
- Under 10 feet: 12AWG minimum
- 10-20 feet: 10AWG
- Over 20 feet: 8AWG
Mistake 3: Wrong Battery Type
Tried using a starting battery once. Died in three months. Deep cycle or marine dual-purpose only.
Mistake 4: Permanent Shadow
Mounted my first panel behind my seat. Guess what cast a shadow all day? Check sun angles before drilling holes.
Mistake 5: Forgetting About Winter
Solar output drops 50-70% in winter. Plan accordingly or you'll be paddling home in December asking yourself why you didn't read this section.
Maintenance and Troubleshooting
Keep your solar system running with minimal effort:
Weekly Maintenance
- Clean panels with water and soft cloth (morning is best)
- Check connections for corrosion (green = bad)
- Monitor charge rates to catch issues early
Monthly Maintenance
- Test battery voltage at rest (should be 12.7V+ for lead-acid)
- Inspect wiring for chafing or damage
- Clean battery terminals with baking soda solution
Common Issues and Fixes:
No charging current:
- Check fuses first (90% of my issues)
- Test panel voltage in sunlight (should be 18-20V for "12V" panel)
- Verify controller lights/display
Slow charging:
- Clean panels thoroughly
- Check for partial shading
- Test each connection for voltage drop
Battery won't hold charge:
- Time for replacement (average 3-5 years for AGM)
- Consider upgrading to lithium
Best Products for Solar Trolling Motor Systems
After testing dozens of components, here's what I actually recommend:
Solar Panels:
Renogy 100W Monocrystalline - Bulletproof reliability, great efficiency, fair price. Running two on my bass boat.
DOKIO 100W Foldable - For kayakers needing portable options. Folds to briefcase size but still delivers serious power.
Charge Controllers:
Victron SmartSolar MPPT 75/15 - Bluetooth monitoring, bulletproof reliability, works with all battery types.
Renogy Wanderer 10A PWM - Budget option that actually works. No bells and whistles but dependable.
Complete Kits:
Renogy 100W Premium Kit - Everything needed for basic setup. Good starting point for beginners.
BougeRV 130W Portable Kit - My go-to recommendation for kayakers. Includes foldable panel and smart controller.
Battery Monitors:
Victron BMV-712 - See exactly what your system is doing via Bluetooth. Worth every penny.
Trolling Motor Battery Charge Time Calculations
Let's get specific about charging math:
The Formula:
Charge Time (hours) = Battery Capacity (Ah) × Depth of Discharge ÷ Solar Panel Current (A) ÷ Efficiency (0.85)
Real Example:
- 100Ah battery at 50% discharge = 50Ah needed
- 100W panel producing 5.5A average
- Charge time = 50 ÷ 5.5 ÷ 0.85 = 10.7 hours
Factors That Affect Trolling Motor Battery Charging Time:
- Temperature: Charging slows below 50°F
- Battery age: Old batteries charge slower
- Cable length: Long runs = voltage drop = slower charging
- Charge controller quality: MPPT charges 30% faster than PWM
Safety and Legal Considerations
Don't skip this part - learned some of these the hard way:
Electrical Safety:
- Always fuse positive connections (panel and battery)
- Use marine-grade components (freshwater corrodes everything)
- Insulate connections properly (heat shrink + liquid electrical tape)
- Ground your system to prevent electrolysis
On-Water Safety:
- Secure panels for rough water (lost one to boat wake)
- Plan for panel failure (always carry backup charging method)
- Consider panel placement for weight distribution
Legal Requirements:
Some states require vessel registration when you add a motor - solar doesn't change this. Check our kayak registration guide for state-specific requirements.
Solar Charging FAQ
Can I charge while using the trolling motor?
Yes, but don't expect miracles. My 100W panel provides about 5A while my motor draws 20-40A. It extends runtime but won't maintain battery level while motoring.
What size solar panel for 24V trolling motor?
Minimum 100W for meaningful charging, ideally 150-200W. I run 200W total (two 100W panels) on my 24V system and can fish all weekend without shore power in summer.
Do I need a special charge controller for lithium batteries?
Yes - lithium requires different charging voltages. Most modern MPPT controllers have lithium settings. Set it wrong and you'll damage expensive batteries.
Can I leave panels connected all the time?
With a proper charge controller, absolutely. My dock setup has been connected 24/7 for three years. The controller prevents overcharging automatically.
Will solar panels drain my battery at night?
Not with a charge controller - they have blocking diodes. Without a controller, panels can drain 1-2Ah overnight (another expensive lesson).
How do I know if my solar setup is working?
Measure battery voltage before and after sunny days. Should gain 0.1-0.3V daily when not using the motor. Better yet, install a battery monitor for real-time data.
My Complete Solar Setup Diagram
Here's exactly how my 24V kayak system is wired:
[100W Panel 1] ←→ [100W Panel 2] (Series Connection)
↓
[30A Fuse Box]
↓
[Victron 100/20 MPPT Controller]
↓
[Battery Switch]
↙ ↘
[100Ah AGM 1] [100Ah AGM 2] (Series for 24V)
↘ ↙
[60A Breaker]
↓
[24V Trolling Motor]
This setup gives me 8-10 hours of fishing time with unlimited range on sunny days. The battery switch lets me isolate batteries for charging or maintenance.
Future of Solar-Powered Trolling
The technology keeps improving. New developments I'm watching:
Flexible Solar Panels
Conforming to kayak curves means more panel area. Testing a 150W flexible panel that covers my entire rear deck.
Integrated Solar Kayaks
Manufacturers are starting to build solar into hull designs. Hobie's prototype has 200W integrated into the deck - game changer for long-distance kayak fishing.
Better Batteries
Solid-state batteries promise 3x capacity at half the weight. When prices drop, solar-powered trolling becomes truly practical for all-day use.
Final Thoughts
After three years of refining my solar setup, I can honestly say it's transformed how I fish. No more range anxiety, no more hauling batteries to the garage, and definitely no more paddling marathons when the battery dies.
Is it perfect? No. Will you run your trolling motor indefinitely on solar alone? Also no. But will a properly designed solar powered trolling motor battery system double or triple your time on the water? Absolutely.
Start simple with a basic maintenance charger, learn your system, then expand as needed. My first 20W panel taught me more than all the forum posts combined. And remember - the best solar setup is the one that keeps you fishing while everyone else heads back to charge.
Got questions about setting up your own solar system? Drop them in the comments below. I check in regularly and love helping folks avoid the mistakes I made. After all, we're all just trying to spend more time on the water, and solar power makes that possible.
See you on the water - I'll be the guy fishing all day without a care about battery levels!