LiTime’s 12V 100Ah TM is a Group 31 lithium battery built for trolling motors from 30 to 70 pounds of thrust, storing 1,280Wh in a case that weighs about 23 pounds. LiTime’s spec sheet lists a 100A battery management system, surges of 300A for five seconds and 500A for one second, an IP65 rating and low-temperature charging protection. Its user manual adds that two identical batteries in series run 24V motors up to 100 lb thrust, and three run 36V motors up to 120 lb.
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I run LiTime batteries in my own setups, including the 12V 50Ah I reviewed after charging it back from 2.7V. This guide covers the TM’s specs, how long it runs a trolling motor, how to wire it for 12, 24 or 36V, and how to charge it correctly. Runtime figures are estimates.
LiTime 12V 100Ah TM specifications
| Spec | LiTime 12V 100Ah TM |
|---|---|
| Chemistry | LiFePO4 (prismatic cells) |
| Nominal voltage / capacity | 12.8V / 100Ah (1,280Wh) |
| BMS | 100A continuous charge and discharge |
| Surge | 300A for 5 s; 500A for 1 s |
| Thrust rating (12V) | 30–70 lb motors |
| Cycle life | 4,000 at 100% DOD; 6,000 at 80%; 15,000 at 60% |
| Charge voltage | 14.4V ± 0.2V |
| Recommended charge current | 20A (0.2C) |
| Charge temperature | 32–122°F; charging stops below 32°F, resumes at 41°F |
| Discharge temperature | -4–140°F; discharge stops below -4°F |
| Expansion | Up to 4 in parallel and 4 in series (4P4S) |
| Protection | IP65 |
| Size / terminals | 13 × 6.77 × 8.43 in (Group 31), M8 bolts |
| Weight | About 23.4 lb (Bluetooth version listed at 22.2 lb) |
| Warranty | 5 years |
Sources: LiTime TM product pages and the 12.8V 100Ah Trolling Motor Smart Battery user manual.
How long will it run a trolling motor?
Runtime is simply amp-hours divided by the motor’s current draw. LiFePO4 holds a nearly flat voltage until it is almost empty, so you can use close to the full 100Ah, unlike lead-acid, which is usually limited to about half its rating.
| Motor draw | Typical situation | Runtime (estimate) |
|---|---|---|
| 10A | Slow trolling, calm water | ~10 hours |
| 20A | Low-medium speed | ~5 hours |
| 30A | Medium speed | ~3.3 hours |
| 40A | Medium-high, light wind | ~2.5 hours |
| 50A+ | Full throttle on a 55 lb motor | ~2 hours or less |
LiTime’s own guidance is similar: 4–6 hours at 20–30A, 2–3 hours at 40–50A and 1–1.5 hours at full throttle. Wind, current, hull weight and GPS anchor functions all add load. Check your motor’s maximum amp draw in its manual.
Worked example: a morning on the lake (estimate)
Two hours of slow trolling at 15A (30Ah), one hour of spot-lock holding against wind averaging 25A (25Ah), and 30 minutes of running between spots at 45A (22.5Ah) totals about 77.5Ah. One TM battery covers it with roughly 20% to spare.
Wiring for 12V, 24V and 36V motors
LiTime’s manual allows identical TM batteries in series for higher-voltage motors:
- 12V motor (up to 70 lb): one battery.
- 24V motor (up to 100 lb): two identical batteries in series, positive of battery 1 to negative of battery 2.
- 36V motor (up to 120 lb): three identical batteries in series.
Use batteries of the same model, age and state of charge, and fully charge each one individually before connecting them in series. LiTime also permits parallel connections for more runtime at the same voltage, up to four in parallel. Our series vs parallel guide shows both layouts.
Fusing and terminals
- Install a fuse or breaker sized to your motor manufacturer’s recommendation on the positive lead, close to the battery.
- Torque the M8 terminal bolts to LiTime’s figure of 106–124 inch-pounds (12–14 N·m).
- Use marine-grade tinned copper cable of the gauge your motor manual specifies.
Charging the TM correctly
- Use a LiFePO4 charger with a 14.4V charge voltage. LiTime recommends 20A for regular charging.
- First use: LiTime recommends a 10A LiFePO4 charger for initial activation of the Bluetooth version.
- Series banks: charge each battery individually, or use a multi-bank charger with one output per battery.
- Cold weather: the BMS blocks charging below 32°F and resumes at 41°F. Bring the battery somewhere warmer before charging in winter.
Worked example: charge time (estimate)
Refilling 77.5Ah with a 20A charger takes roughly 4 hours (77.5 ÷ 20), plus a short absorption stage at the end. A 10A charger takes about 8 hours.
I use the LiTime 12V 20A lithium charger, which I reviewed separately.
Storage between seasons
LiTime lists a storage range of 14–122°F. Before putting the boat away for winter, charge the battery to a partial or full state, disconnect it from the motor and any electronics so nothing slowly drains it, and store it somewhere dry inside that range. Check the charge every few months, using the Bluetooth app on the smart version or a voltmeter on the standard one, and top it up if it has dropped. A LiFePO4 battery’s low self-discharge means it usually needs little attention over a winter.
Why lithium for a trolling motor
- Weight: LiTime says the TM is about one-fifth the weight of a 12V 200Ah lead-acid battery with similar usable energy.
- Steady speed: flat voltage means the motor keeps its speed until the battery is nearly empty.
- Cycle life: 4,000 full cycles versus a few hundred for typical lead-acid deep-cycle batteries.
Note that LiTime marks the TM as not for engine starting. Keep a separate starting battery for an outboard.
Matching the TM to your boat
A common rule of thumb from trolling motor makers is at least 2 lb of thrust for every 100 lb of fully loaded boat weight (hull, motor, fuel, gear and people), with more if you fish in wind or current. Here’s how that lines up with the TM’s ratings:
| Loaded boat weight | Thrust by rule of thumb | Typical motor choice | LiTime TM setup |
|---|---|---|---|
| ~1,500 lb (jon boat, small aluminum) | 30+ lb | 30–45 lb, 12V | 1 battery |
| ~2,500 lb (16–17 ft fishing boat) | 50+ lb | 55 lb, 12V | 1 battery, or 2 in parallel for longer days |
| ~3,500 lb (18–19 ft bass or bay boat) | 70+ lb | 70–80 lb, 24V | 2 in series |
| ~5,000 lb (larger bay or walleye boat) | 100+ lb | 100–112 lb, 36V | 3 in series |
These are rules of thumb, not maker requirements. Always follow the voltage your motor is built for, and stay within the thrust ranges LiTime lists for 12V, 24V and 36V setups.
Find your real amp draw
The runtime table above depends on how much current your motor actually pulls. There are three easy ways to find out:
- Bluetooth app: on the Bluetooth version, the LiTime app shows live current. Run the motor at each speed setting for a minute and write the numbers down.
- Clamp meter: a DC clamp meter around the positive lead gives the same reading on the standard version.
- Motor manual: most manuals list the maximum amp draw. Treat that as the worst case at full throttle.
Worked example: two batteries in parallel (estimate)
If a 55 lb motor averages 25A over a full day of fishing, one TM lasts about four hours (100 ÷ 25). Two in parallel give 200Ah, or about eight hours, at the same 12V. Charge both fully and connect them with equal-length cables so they share the load evenly.
Where to buy
LiTime sells the 12V 100Ah TM in standard and Bluetooth versions. You can also find the LiTime 12V 100Ah trolling motor battery on Amazon.
Related reading
- LiTime 12V 50Ah review: charging from 2.7V to 100%
- LiTime 12V 20A charger review
- How long will a 100Ah battery last?
FAQ
What size trolling motor can the LiTime 100Ah TM run?
One battery suits 12V motors from 30 to 70 lb thrust. Two in series run 24V motors up to 100 lb, and three run 36V motors up to 120 lb, per LiTime.
How long does a 100Ah lithium battery last on a trolling motor?
About 3.3 hours at a steady 30A and around 10 hours at 10A (estimate).
Can I charge it with my old lead-acid charger?
Use a charger with a LiFePO4 profile and a 14.4V charge voltage, as LiTime specifies.
Can it be charged in freezing weather?
No. The BMS stops charging below 32°F and resumes above 41°F.
Is it waterproof?
It is rated IP65, meaning dust-tight and protected against water jets.
Can I run my fish finder from the same battery?
You can, but many anglers keep electronics on a separate small battery. That keeps the motor’s heavy, changing draw away from the sonar and saves trolling runtime.
Do I need two batteries for a 24V motor?
Yes. A 24V motor needs two identical TM batteries in series, each fully charged on its own before you connect them, per LiTime’s manual.
Is the Bluetooth version worth it?
If you want to see live current, voltage and state of charge on your phone, yes. It makes it easy to measure your motor’s real draw and plan runtime. If you only need a battery that works, the standard version stores the same 1,280Wh.