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Group 27 Trolling Motor Battery Guide: Pro-Guide 27M180 (180 RC)
Short answer: The Pro-Guide 27M180 is a 12V Group 27 flooded deep cycle trolling motor battery with 180 minutes of reserve capacity at 25 amps, 675 CCA and 825 MCA, in a 12 1/16 x 6 13/16 x 8 7/8 in case weighing 50 lb. It has the most reserve capacity of any Pro-Guide Group 27 lead-acid deep cycle battery, so it is the flooded pick for anglers who want the longest trolling motor run time a Group 27 tray can hold, alone at 12V or wired in series for 24V and 36V motors.
A trolling motor is the hardest job you can give a deep cycle battery: high current, for hours, day after day. This guide explains how to size a Group 27 trolling motor battery, what 180 minutes of reserve capacity means on the water, how to build 24V and 36V banks with the 27M180, how flooded stacks up against AGM and lithium, and how to charge and water it so it keeps pulling all season.
Key Takeaways
- Most reserve capacity of any Pro-Guide Group 27 lead-acid deep cycle battery: 180 minutes at 25 amps, about 75 amp-hours delivered at that rate.
- Built for trolling motors: run one at 12V, two in series for 24V or three in series for 36V.
- Conservative working budget: about 37Ah per trip if you recharge at roughly 50%.
- Serviceable flooded design: top up with distilled water from time to time.
- Charging: 10A standard, 15A maximum per battery, flooded lead-acid profile.
- Warranty: 12 months free replacement and 30 months total pro-rata.
What Makes a Good Group 27 Trolling Motor Battery?
Group 27 is a Battery Council International (BCI) case size. It is about 1 13/16 inches longer than a Group 24, and that extra length usually means more lead and more capacity. For bass boats, multi-species boats and pontoons with Group 27 trays, it is often the sweet spot between capacity, weight and fit.
Beyond size, three things matter most in a trolling motor battery:
- Deep cycle construction. Starting batteries are built for short, high bursts. Trolling motors need a battery designed to be drawn down and recharged again and again.
- Reserve capacity. RC tells you how long a battery can hold a 25-amp load, which is right in the range of a 12V trolling motor at moderate speed. More minutes means more time on the spot-lock or working a bank.
- Matched batteries. In a 24V or 36V system, each battery should be the same model and age so they charge and discharge evenly.
The Pro-Guide 27M180 checks all three: deep cycle flooded lead-acid construction, the highest reserve capacity of Pro-Guide's Group 27 lead-acid deep cycle batteries and a single model you can match across a 24V or 36V bank.
Pro-Guide 27M180 Specifications
| Model / SKU | Pro-Guide 27M180 (PGM27M180) |
| Type | 12V flooded lead-acid deep cycle |
| BCI group size | Group 27 |
| Reserve capacity | 180 minutes at 25 amps |
| Cold cranking amps (CCA) | 675 CCA |
| Marine cranking amps | 825 |
| Charge current | 10A standard / 15A maximum |
| Terminals | 1 SAE post, 1 stud terminal |
| Dimensions | 12 1/16 x 6 13/16 x 8 7/8 in (306.4 x 174.6 x 228.6 mm) |
| Weight | 50 lb (22.7 kg) |
| Warranty | 12 months free replacement, 30 months total pro-rata |
The height listed is the case height; allow extra clearance for the terminals and cable lugs under your deck lid or battery box cover.
The 27M180 uses a standard Group 27 case with a built-in carry handle and both SAE post and stud terminals.
How Long Will the 27M180 Run a Trolling Motor?
Reserve capacity is the number of minutes a fully charged battery can deliver 25 amps before falling to 10.5 volts. At 180 minutes, the 27M180 delivers about 75 amp-hours at that rate (25A x 180 / 60). That is a ballpark, not a rated Ah number: lead-acid batteries typically give a bit more total capacity at light draws and less at heavy draws.
Running any lead-acid battery to 10.5V shortens its life, so plan to use about 50% and then recharge. That gives the 27M180 a working budget of roughly 37 amp-hours per trip.
| Average trolling motor draw | Typical use | Rough runtime to ~50% on one 27M180 |
| About 10A | Slow trolling, calm water | About 3.5 to 4 hours of motor-on time |
| About 15A | Steady moderate speed | About 2.5 hours |
| About 25A | Pushing into wind or current | About 90 minutes |
| About 40A+ | Near full throttle | Under 1 hour, and heavy draws reduce real capacity further |
Few anglers run the motor nonstop. If you bump it on and off to hold position, your average current drops a lot, and one battery can cover a much longer day. Check your motor's manual for its current draw at each speed and multiply by the minutes you actually run it. Wind, current, boat weight and cold water all cut real runtime.
12V, 24V and 36V Setups with the 27M180
Trolling motors are sold in 12V, 24V and 36V versions. You build the higher voltages by wiring identical 12V batteries in series, positive of one to negative of the next. Series wiring adds voltage while the amp-hour rating of the bank stays the same as one battery.
| Motor voltage | 27M180 batteries | Wiring | Approx. bank weight |
| 12V | 1 | Single battery | 50 lb |
| 24V | 2 | 2 in series | 100 lb |
| 36V | 3 | 3 in series | 150 lb |
A higher-voltage motor draws less current for the same thrust, so the same batteries usually last longer in a 24V or 36V system. Always use matched batteries of the same model and age, and charge each battery in the bank with its own charger bank. For wiring diagrams and the pros and cons of each layout, read One Pack or Three? Choosing the Right Trolling Motor Battery Setup.
Flooded vs. AGM vs. Lithium for Trolling Motors
| Factor | 27M180 (flooded) | Group 27 AGM | 12V 100Ah lithium (24M100) |
| Reserve capacity | 180 min at 25A | 175 min at 25A | Not rated by RC; 100Ah |
| Usable capacity | About 50% for long life | About 50% for long life | Nearly all of 100Ah |
| Weight per battery | 50 lb | 50 lb | 23.8 lb |
| 36V bank weight | About 150 lb | About 150 lb | About 71 lb |
| Voltage under load | Sags as it discharges | Sags as it discharges | Stays flat until nearly empty |
| Maintenance | Water checks | Sealed, no watering | None |
| Upfront cost | Lowest | Middle | Highest |
Flooded batteries are the budget-friendly way to power a trolling motor, and the 27M180 gives you the most flooded runtime that fits a Group 27 tray. AGM keeps the weight about the same but removes watering. Lithium cuts a 36V bank's weight roughly in half, holds steady voltage so the motor doesn't slow down late in the day, and is rated for thousands of cycles, at a higher upfront price. See all deep cycle lithium batteries if weight is your top concern.
What Is the 27M180 Best For?
- Trolling motors on bass, multi-species and pontoon boats: single 12V motors or matched 24V and 36V banks. Browse all trolling motor batteries.
- Electronics and house loads: a dedicated battery for graphs, sonar, livewells and lights. Read Should You Run a Separate Battery for Your Boat Electronics?
- RV and camper house power: the extra reserve capacity helps on longer dry-camping stretches. See RV and van life batteries.
- Solar and off-grid storage: an affordable flooded battery for cabins and small solar systems.
The label shows the 27M180's ratings at a glance: 825 MCA, 675 CCA and 180 minutes of reserve capacity.
How to Charge a Flooded Trolling Motor Battery
Each 27M180 is rated for a 10A standard and 15A maximum charge current. A rough charge-time estimate is amp-hours used divided by charger amps, plus about 20% for the final absorption stage. From about 50% (roughly 37Ah used), a 10A charger bank needs about 4.5 hours per battery.
- Give every battery its own charger bank. Pro-Guide on-board chargers have one bank per battery, and each bank can run a lead-acid profile (14.1 to 14.3V). Use the 12V 10A 1-Bank for a single 12V battery, the 12V 10A 2-Bank for a 24V bank and the 12V 10A 3-Bank for a 36V bank. Add a bank if you also charge a cranking battery.
- Stay at or under 15A per battery. Too much current overheats flooded batteries and boils off water.
- Plug in after every trip. Lead-acid batteries that sit partly discharged sulfate and lose capacity.
- Vent the compartment. Flooded batteries typically release hydrogen near the end of a charge. Keep sparks away from the battery area.
For a 12V motor, the 12 Volt Trolling Motor Kit with On-Board Charging Connection Kit makes the wiring and charger hookup simple.
Watering and Maintenance Tips for the 27M180
Top up with distilled water
The 27M180 is a serviceable flooded battery. Check the electrolyte level every few weeks of heavy use. With the battery cool and upright, make sure the plates are covered, and top up with distilled water only, typically after charging. Trolling motor batteries work hard and usually need water more often than house batteries.
Check each battery in the bank
In a 24V or 36V bank, test resting voltage on each battery separately. On flooded batteries a hydrometer also reads specific gravity cell by cell. One battery that reads lower than the others is a sign of a weak cell or a charger bank problem.
Equalize carefully, if at all
Pro-Guide does not publish an equalization procedure for the 27M180. If your charger offers equalization for flooded batteries, follow its instructions exactly and call our team with questions first.
Mount it upright and tight
Flooded batteries must stay upright. Strap each one down in a Group 27 box or tray such as the NOCO Group 27 Snap-Top Battery Box or the NOCO Group 27 Battery Tray, and protect the terminals with battery corrosion preventative spray.
Winterize charged
Fully charge the bank before storage and keep it on a maintainer or check it monthly. See Marine Battery Maintenance: 7 Tips to Keep Your Batteries Ready for more.
27M180 vs. 27M800: Deep Cycle or Dual Purpose?
| Spec | Pro-Guide 27M180 (deep cycle) | Pro-Guide 27M800 (dual purpose) | Pro-Guide 27M160 (deep cycle) |
| Reserve capacity | 180 min | 182 min | 160 min |
| CCA | 675 | 800 | 600 |
| Weight | 50 lb | 49 lb | 47 lb |
| Main job | Trolling motor and house loads | Engine starting plus accessories | Lighter-duty house and trolling loads |
Pick the 27M180 for batteries that only power a trolling motor or house loads, where deep cycling is the whole job. Pick the 27M800 if one battery has to crank your outboard and also run accessories. Pick the 27M160 if you want the same Group 27 case for lighter use at a lower price.
Frequently Asked Questions
What is the best Group 27 flooded battery for a trolling motor?
In the Pro-Guide line, the 27M180 has the most reserve capacity of any Group 27 lead-acid deep cycle battery: 180 minutes at 25 amps. That makes it the longest-running Pro-Guide flooded deep cycle option for a Group 27 trolling motor tray.
How many amp-hours is the Pro-Guide 27M180?
Pro-Guide rates the 27M180 by reserve capacity, 180 minutes at 25A, which works out to roughly 75Ah delivered at that rate. Plan to use about 37Ah per trip for long battery life.
How many 27M180 batteries do I need for a 36V trolling motor?
Three. Wire three matched 27M180 batteries in series for 36V, or two in series for a 24V motor.
How long will a 27M180 run my trolling motor?
At a steady 25A draw, expect about 90 minutes of motor-on time before reaching roughly 50% charge. At 10A, expect about 3.5 to 4 hours. Real runtime depends on speed, wind and current.
What charger do I need for a 27M180 bank?
Use an on-board charger with one bank per battery and a flooded lead-acid profile, at 15A or less per battery. A Pro-Guide 12V 10A 3-Bank charger fits a 36V bank of three.
Do I need to add water to the 27M180?
Yes. Check the electrolyte level regularly and top up with distilled water only, ideally after charging.
What warranty comes with the 27M180?
The 27M180 has a 12-month free replacement warranty and 30 months of total pro-rata coverage. Register your battery online to activate coverage.
Get More Time on the Water
If your boat has Group 27 trays and you want the most flooded trolling motor runtime that fits, the Pro-Guide 27M180 is the one to choose, whether you run one battery at 12V or a matched bank at 24V or 36V. It is sold through our dealer network, so call us and we will point you to the closest dealer and help you match batteries and chargers.
Need help planning a 24V or 36V bank? Call our team at 1-800-827-3232 or browse all trolling motor batteries and battery chargers.
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