Trolling Motor Batteries
LiTime 36V 50Ah Review: The 120 Pound Argument for Lithium
Quick answer
The LiTime 36V 50Ah is a single LiFePO4 pack built for motors up to 120 lb of thrust, replacing three 12 volt lead acid batteries and removing roughly 120 lb from the boat, though it only works safely on a charger built with a lithium profile.
The LiTime 36V 50Ah is one of the cheapest ways into a 36 volt lithium bank, and the real case for it has less to do with fishing than with what comes out of the boat. A 36 volt lead acid system means three 12 volt batteries wired in series, each commonly in the 55 to 65 lb range once a battery box and cables are added, so a lead acid bank at this voltage typically runs close to 180 lb before anything else gets counted. This review is built from LiTime's own published specifications and the consensus of verified owner reviews rather than a pack tested in person.
Fifty amp hours sounds modest next to a 100Ah lead acid battery, but LiFePO4 delivers close to its full rating at a trolling motor draw the way lead acid does not, and LiTime rates this pack for motors up to 120 lb of thrust. The number worth sitting with before buying is the charger: this pack, like every lithium battery, needs a charger built with a lithium profile, and getting that wrong is the single most expensive mistake in this category.
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What does LiTime actually publish about the 36V 50Ah?
The LiTime 36V 50Ah TM LiFePO4 battery with low temperature protection ships as a single Group 31 sized case built around automotive grade LiFePO4 cells, with a built in BMS rated for a continuous 50A discharge and a 60A surge for up to 30 minutes. LiTime states the pack suits trolling motors up to 120 lb of thrust, which covers everything up through a 36 volt Terrova 112 without going anywhere near the surge ceiling. LiTime also publishes an energy density of 57.93 Wh per lb, calculated from a 1,920 Wh capacity against a 33.14 lb weight, a figure it states beats a typical 12V 100Ah lithium pack by roughly 11 percent, and states the pack meets the ABYC E-13 standard for lithium marine batteries.
How much does going lithium actually save in weight?
Nobody weighs three lead acid batteries against one lithium pack at the counter, so this is the sum worth doing before spending the money.
Swapping three lead acid batteries for the LiTime 36V 50Ah removes on the order of 120 to 150 lb from the boat.
Rule of thumb Boating and fishing convention rather than a published standard. Taught everywhere, useful, and not a specification. Nothing enforces it and no body publishes it.
| System | Approximate weight | Basis |
|---|---|---|
| Three 12V AGM batteries (Group 27/31, roughly 55 to 65 lb each) | 165 to 195 lb | Convention, brand dependent |
| LiTime 36V 50Ah pack | 33.14 lb | LiTime published |
| Weight removed | roughly 130 to 160 lb | Convention estimate |
Lead acid weight varies by brand and case size, so treat the lead acid figures as a planning range rather than a fixed number. LiTime's own 33.14 lb figure for the pack is the one hard number in this comparison, and the rest is a reasonable estimate rather than a specification.
What do the published Peukert numbers actually mean for this pack?
Peukert's equation is published battery engineering, and the exponent is the one number that explains why a lead acid battery of similar rated capacity cannot keep up with this pack at a real trolling motor draw.
LiFePO4's Peukert exponent of 1.02 is close enough to flat that this pack delivers nearly its full rating under load, unlike flooded or AGM lead acid.
Published figure A published engineering, regulatory or manufacturer figure. It does not change because somebody disagrees with it.
| Chemistry | Peukert exponent | Usable depth of discharge |
|---|---|---|
| Flooded lead acid | 1.25 | 50%, convention |
| AGM lead acid | 1.15 | 50%, convention |
| LiFePO4 (this pack) | 1.02 | 80%, planning figure |
The Peukert exponent is published battery engineering and does not change by brand. The depth of discharge figures alongside it are conventions used to protect cycle life, not hard cutoffs the battery enforces.
Where 50Ah runs out, and what it costs you
Fifty amp hours covers most fishing days on a mid size trolling motor, but it is not enough for everyone, and LiTime's own lineup makes that plain: the LiTime 36V 100Ah exists specifically because 50Ah runs out on long days with a heavier draw. The real limitation on the pack reviewed here is that its 50A continuous rating and 30 minute 60A surge cap the largest motors in this catalog; a motor pulling close to that ceiling at wide open throttle for extended periods leaves less margin than the same motor would have on a lead acid bank sized specifically around it. Price is the other honest cost: at roughly four to five times a single lead acid battery, and closer to double a full three battery lead acid bank, this pack earns its premium back in weight and run time rather than at the register.
Step up, or save money on lead acid instead
Step up to the LiTime 36V 100Ah when the motor draw or the length of the day regularly pushes past what 50Ah can deliver; it doubles the capacity, and while the weight savings shrink relative to lead acid at that capacity, it still removes well over 100 lb versus three lead acid batteries sized to match. The LiTime 36V 50Ah Bluetooth version bundles a charger that already carries the correct lithium profile, which removes the single most common mistake buyers make with this pack. A genuine budget pick exists too: three VMAX MR137-120 AGM batteries wired in series cost meaningfully less up front, at the price of roughly 150 lb more weight on the boat and a real ceiling on how much of that rated capacity is actually usable at a trolling motor draw.
Sources
- LiTime published specifications for the 36V 50Ah TM LiFePO4 trolling motor battery
- LiTime published specifications for the 36V 100Ah lithium battery
- Recurring themes in verified owner reviews of the LiTime 36V lineup
Frequently asked questions
Does the LiTime 36V 50Ah need a special charger?
Yes. This pack needs a charger built with a lithium profile, not a lead acid profile. A lead acid charge curve either never reaches the bulk voltage a LiFePO4 pack needs to actually finish charging, or it holds the pack afterward at a float voltage lithium cells should not sit at for long periods. Chargers like the NOCO GENPRO10X3 or the Minn Kota MK-345PCL publish a selectable lithium mode on every bank, which is the specification to check before buying either the battery or the charger.
How much thrust can the LiTime 36V 50Ah actually run?
LiTime states the pack suits trolling motors up to 120 lb of thrust, backed by a published continuous discharge rating of 50A and a 60A surge for up to 30 minutes. That covers every mainstream 36 volt motor on the market, including 112 lb thrust bow motors, without pushing the pack anywhere near its surge ceiling during normal operation at full throttle.
How much weight does this pack actually save over lead acid?
LiTime publishes the pack's own weight at 33.14 lb. A typical 36 volt lead acid bank of three Group 27 or 31 batteries commonly runs somewhere between 165 and 195 lb depending on brand, so swapping to this pack removes roughly 130 to 160 lb from the boat. Treat that range as a convention rather than a precise figure, since lead acid weight varies meaningfully between manufacturers and case sizes.
Is 50Ah enough for a full day of fishing?
For most trolling motor use, yes, especially given LiFePO4's low Peukert exponent of 1.02 and a planning depth of discharge around 80 percent, both of which let this pack deliver close to its full rating rather than the fraction a lead acid battery of similar rating would return at the same draw. Anyone regularly running heavy continuous draw across long days should look at the 100Ah version instead of stretching the 50Ah pack past a comfortable margin.
Does the LiTime 36V 50Ah meet a marine lithium safety standard?
LiTime states the pack meets the ABYC E-13 standard, which is the American Boat and Yacht Council's standard covering the safety protections expected of a marine lithium battery, including overcharge, over-discharge and short circuit protection built into the BMS. That is a real published standard rather than marketing language, and it is worth confirming on any lithium pack before it goes anywhere near a boat.
What is the cheaper lead acid alternative, and what does it cost in weight?
Three VMAX MR137-120 Group 31 AGM batteries wired in series build a comparable 36 volt bank at meaningfully less upfront cost than this lithium pack. The tradeoff is roughly 150 lb more weight on the boat, a real ceiling on how much of the rated 120Ah is usable at a trolling motor draw under the 50 percent depth of discharge convention, and a shorter cycle life than LiFePO4 delivers over several seasons of use.
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Researched, not professional advice. This page is compiled from published engineering and regulatory figures, manufacturer specifications and owner-review consensus, not hands-on testing. Figures described as a rule of thumb are boating convention rather than published standards, and they are labelled that way wherever they appear. Marine electrical work is not house wiring. Use tinned, finely stranded marine cable, size it for voltage drop and for the ABYC E-11 ampacity table rather than one or the other, and put overcurrent protection within seven inches of the battery positive terminal, because everything between the post and the fuse is unprotected. A lithium battery needs a charger with a lithium profile. Never load a boat past its capacity plate, and remember that canoes and kayaks carry no federal capacity plate at all, so their stated capacity is the manufacturer own figure. Wear the life jacket, and treat early season water as the hazard it is: cold water immersion takes your breath and then your hands long before it takes your core.