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12V 24Ah Lithium Battery Guide: Slim LiFePO4 Power for Kayaks
Short answer: A 12V 24Ah lithium battery like the Pro-Guide PGLM24 is a 12.8V LiFePO4 deep cycle battery that stores 307.2 watt-hours in a slim case just 3 in wide (7.13 x 3 x 6.5 in) and weighs 6.61 lb. It runs a 2A kayak fish finder for about 12 hours, is IP65 rated, and is rated for 3,000 cycles at 100% depth of discharge, which makes it one of the easiest ways to power kayak electronics all day.
In a kayak, space and weight decide everything. A battery has to fit in a hatch, a crate or a bag, and it has to be light enough that you are not fighting it at the launch. This guide explains what a 12V 24Ah LiFePO4 battery can do, how long it runs common kayak loads, how it compares with lead-acid and AGM, how to charge it by the numbers on its label, and how to choose between the PGLM24 and its smaller and larger Pro-Guide siblings.
Key Takeaways
- Slim fit: 3 in wide, 7.13 in long and 6.5 in tall (181 x 76.2 x 165.1 mm), so it slides into narrow kayak hatches and battery bags.
- Light: 6.61 lb (3 kg) for 307.2Wh of energy.
- All-day sonar: about 12 hours on a 2A fish finder, about 24 hours on a 1A load.
- Long life: 3,000 cycles at 100% depth of discharge and 6,000 cycles at 80%.
- Splash-ready: IP65 rated case with built-in protection against over-charge, over-discharge, over-current, over-temperature and short circuit, plus cell balancing.
- Warranty: 3-year free replacement and 5-year pro-rata.
What Is a 12V 24Ah Lithium Battery?
A 12V 24Ah lithium battery is a 12-volt battery that can deliver about 24 amp-hours of current: roughly 1 amp for 24 hours or 2 amps for 12 hours. The PGLM24 is labeled 12.8V nominal, so its stored energy is 12.8V x 24Ah = 307.2 watt-hours.
It uses lithium iron phosphate (LiFePO4) cells, the chemistry Pro-Guide uses across its lithium line. LiFePO4 is valued for a long cycle life, a flat discharge curve and stable, safe behavior. For kayak anglers, the practical benefits are simple: more usable runtime per pound, steady voltage for your electronics, and a battery that lasts for years of trips.
The PGLM24 does not use a standard BCI group-size case. Its tall, narrow shape is the point: at 3 in wide it fits places a Group U1 or Group 24 battery cannot. Always measure your hatch, crate or battery bag before you buy.
Pro-Guide PGLM24 Specifications
| Model / SKU | Pro-Guide PGLM24 |
| Chemistry | Lithium iron phosphate (LiFePO4) |
| Nominal voltage | 12.8V |
| Capacity / energy | 24Ah / 307.2Wh |
| Cycle life | 3,000 cycles at 100% DoD, 6,000 at 80% DoD |
| Discharge current | 4.8A standard, 30A maximum continuous, 190A peak for 100 milliseconds |
| Discharge cut-off | 10V |
| Charge voltage | 14.6V (±0.2V) |
| Charging temperature | 32°F to 131°F (0°C to 55°C) |
| Discharge temperature | -4°F to 140°F (-20°C to 60°C) |
| Self-discharge | Less than 3% per month |
| Protection | IP65 plastic case; over-charge, over-discharge, over-current, over-temperature and short-circuit protection; cell balancing |
| Terminals | Internal thread (M5) |
| Bluetooth | Enabled |
| Dimensions | 7.13 x 3 x 6.5 in (181 x 76.2 x 165.1 mm) |
| Weight | 6.61 lb (3 kg) |
| Warranty | 36-month free replacement, 60-month total pro-rata |
Want the full numbers? Download the PGLM24 data sheet (PDF).
The PGLM24's narrow 3 in case is built for tight kayak hatches and battery bags.
How Long Will a 12V 24Ah Lithium Battery Last in a Kayak?
Divide 24Ah by the total current your electronics draw. Add up every device on the battery: a fish finder, a GPS, navigation lights and a bilge or livewell pump all count. Your device manuals list the draw in amps or watts (divide watts by 12 to get amps).
| Kayak load | Draw | Estimated runtime on the PGLM24 |
| Compact fish finder | About 1A | About 24 hours |
| Mid-size fish finder | About 2A | About 12 hours |
| Fish finder plus lights and a small pump | About 4.8A | About 5 hours |
| Larger electronics load | About 10A | About 2.4 hours |
These are rough estimates. Real runtime depends on the load, temperature and how far you discharge the battery. Because the PGLM24 can use nearly all of its rated capacity and holds steady voltage as it drains, these numbers are closer to real life than the same math on a lead-acid battery.
The PGLM24 is rated for up to 30A continuous discharge, with a 190A peak for 100 milliseconds. That gives headroom for multiple devices at once, but if you plan to run a kayak trolling motor, compare its rated draw against those limits and against your runtime needs. Most anglers who want to push a kayak motor for hours step up to a larger battery such as the PGLM50.
24Ah Lithium vs. AGM and Lead-Acid for Kayaks
Here is how a 24Ah LiFePO4 battery typically compares with lead-acid and AGM options for kayak use.
| Factor | Pro-Guide PGLM24 (LiFePO4) | Typical AGM / lead-acid |
| Usable capacity | Nearly all of 24Ah | About 50% of rated capacity to protect battery life |
| Weight | 6.61 lb | Typically much heavier for the same usable energy |
| Cycle life | 3,000 at 100% DoD | Typically a few hundred cycles |
| Voltage under load | Stays flat until nearly empty | Sags steadily as it discharges |
| Self-discharge | Less than 3% per month | Usually higher, needs regular top-ups in storage |
| Water resistance | IP65 case | Varies by model |
For a kayak angler, the usable-capacity difference is the big one. To get 24Ah of practical runtime from lead-acid, you would typically need a battery rated near 50Ah, and you would carry its weight down to the water every trip. The PGLM24 gives you that runtime at 6.61 lb.
What Is the PGLM24 Best For?
- Kayak fish finders: a full day of sonar on a typical 2A unit, in a case narrow enough for most hatches and crates.
- Canoes, float tubes and small boats: anywhere you carry your power in and out.
- A dedicated electronics battery: isolating your graph from the motor battery gives cleaner sonar. Read Should You Run a Separate Battery for Your Boat Electronics?
- Light RV, camping and solar storage: 307.2Wh for lights, fans and device charging, with a cycle life that suits regular use.
The PGLM24 is a deep cycle battery. It is not designed to start an engine.
The PGLM24's top label lists its charging limits and a quick voltage guide: 13.8V at 100% and 13.1V at 20%.
How to Charge the PGLM24
The label on top of the PGLM24 gives clear charging rules. Follow them and the battery will reach its full rated life:
- Use a lithium-specific charger. Set the charge voltage between 14V and 15V; Pro-Guide specifies 14.6V (±0.2V). Never exceed 15V.
- Charge at a gentle current. The label lists a standard charge current of 4.8A and a maximum of 12A, and advises always charging below the maximum. At 4.8A, a full charge from empty takes about 5 hours.
- Turn off desulfation. Do not use a charger with an automatic "desulfation mode."
- Charge between 32°F and 131°F. The PGLM24 can power electronics down to -4°F, but bring it inside to warm up before charging after a cold morning.
- Never let it drop below 8V. The label warns that discharging below 8.0V damages the battery and voids the warranty. The built-in protection has a 10V discharge cut-off, so recharge promptly after it shuts off.
- Check voltage after resting. Wait 1 to 2 hours after charging. The label lists about 13.8V at 100% and 13.1V at 20%; if it reads below 12.8V, it needs more charging.
The Pro-Guide 12V 10A 1-Bank Battery Charger has a 12V lithium profile and an activation mode, and its 10A output stays under the PGLM24's 12A maximum, for about a 2.5-hour charge from empty.
Kayak Installation Tips
Measure the hatch, not just the battery
The PGLM24 is 6.5 in tall. Measure your hatch opening, the depth below it, and the clearance for the terminal bolts and cable lugs, not just the floor space.
Use the right terminal hardware
The PGLM24 has internal-thread M5 terminals. Use M5 bolts of the correct length and ring terminals sized for your wire, and tighten firmly without forcing the threads.
Fuse the positive lead
Put an inline fuse close to the battery on the positive cable, sized to your electronics manufacturer's recommendation. It protects your wiring and your kayak.
Keep it dry and secured
IP65 means dust-tight and protected against low-pressure water jets; it is not rated for immersion. Keep the battery in a bag, box or mount out of standing water, and strap it down so it cannot shift.
Don't wire it in series
The label says do not connect the PGLM24 in series, and do not connect more than 4 in parallel. For more 12V runtime, parallel identical batteries or move up to a single larger battery.
Check state of charge from your phone
Bluetooth is listed as enabled on the PGLM24, and the product page links to the Pro-Guide Power iOS app, so you can check charge before you load the kayak.
PGLM24 vs. PGLM10 and PGLM50: Which Size Do You Need?
| Spec | PGLM10 | PGLM24 | PGLM50 |
| Capacity / energy | 10Ah / 128Wh | 24Ah / 307.2Wh | 50Ah / 640Wh |
| 2A fish finder runtime | About 5 hours | About 12 hours | About 25 hours |
| Width | 2.5 in | 3 in | 6.5 in |
| Weight | 2.65 lb | 6.61 lb | 14 lb |
Choose the PGLM10 for short trips and the lightest possible kit. Choose the PGLM24 for a full day of kayak sonar in a slim case. Choose the PGLM50 if you run multiple graphs, forward-facing sonar or a kayak trolling motor and have room for a wider box.
Frequently Asked Questions
How long will a 12V 24Ah lithium battery run a fish finder?
Divide 24Ah by the draw. The Pro-Guide PGLM24 runs a 2A fish finder for about 12 hours and a 1A unit for about 24 hours. Actual runtime depends on load and temperature.
How big is the PGLM24?
The PGLM24 measures 7.13 x 3 x 6.5 in (181 x 76.2 x 165.1 mm) and weighs 6.61 lb. It is not a standard group size, so measure your hatch or bag first.
Is the PGLM24 waterproof?
It is IP65 rated: dust-tight and protected against low-pressure water jets. It is not rated for immersion, so keep it out of standing water.
How fast can I charge the PGLM24?
The battery label lists a 4.8A standard and 12A maximum charge current at 14V to 15V. At 4.8A, a full charge from empty takes about 5 hours.
Can I charge the PGLM24 in cold weather?
Charge it between 32°F and 131°F (0°C to 55°C). It can discharge down to -4°F, so it can run electronics in colder weather than it should be charged in.
Can I use the PGLM24 for a kayak trolling motor?
The PGLM24 supports up to 30A continuous, but its 24Ah capacity limits motor runtime. Anglers who rely on a kayak trolling motor usually choose a larger battery like the Pro-Guide PGLM50.
How many cycles does the PGLM24 last?
The PGLM24 is rated for 3,000 cycles at 100% depth of discharge and 6,000 cycles at 80% depth of discharge.
Power Your Kayak with the PGLM24
If you want a full day of fish finder power in a battery that slips into a narrow hatch and weighs 6.61 lb, the Pro-Guide PGLM24 is built for it: 307.2Wh of LiFePO4 energy, an IP65 case, 3,000 cycles at 100% depth of discharge and a 5-year warranty.
Questions about your kayak setup? Call our team at 1-800-827-3232 or browse all deep cycle lithium batteries and battery chargers.
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