What Size Battery Do I Need for a 55 lb Trolling Motor?
55 lb is the top of Minn Kota's one-battery class, and 50 A is the draw used for the worst-case hour example.
Direct answer: Minn Kota lists the 50/55 lb class at 50 A and 12 V, with one 12 V battery because thrust at or under 55 lb does not step up to 24 V (Minn Kota battery chart; Minn Kota power article). The runtime recommendation is still at least 110 Ah per battery for 6–8 hours. Dividing that 110 Ah by the 50 A maximum gives 2.2 hours at full draw, and the chart says to treat maximum amp draw as intermittent, so 2.2 hours is a worst case (Minn Kota battery chart; Minn Kota power article).
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The 2-hour-class worst case is arithmetic on Minn Kota's 110 Ah guide and the 50 A maximum. It is not a claim that a 55 lb motor only runs that long in a normal day.
The chart groups 50 lb and 55 lb together: 50 A at 12 V (Minn Kota battery chart). Use 50 A for this motor, not the 42 A figure that belongs to the 40/45 lb row.
Count is still one battery. The help article steps to two batteries only above 55 lb (Minn Kota power article). A 55 lb motor is the last single-battery case, not the first 24 V case.
Ask for at least 110 Ah even though the worst-case math is short of an 8-hour day. 110 ÷ 50 = 2.2 hours at the maximum. The 6–8 hour sentence and the 2.2 hour floor are both in the sources; they describe different things. 6–8 hours is the general recommendation at a 110 Ah rating. 2.2 hours is what you get if the motor sat on its maximum the whole time, which the chart says it does not (Minn Kota power article; Minn Kota battery chart).
Group 27 Better is listed at 85–110 Ah, so only a group 27 at the 110 Ah end meets the guide. Group 24 Good at 70–85 Ah does not. Group 31 Best at 95–125 Ah is the range that can clear 110 Ah with room (Minn Kota battery chart).
Lithium has to cover 50 A continuously (Minn Kota power article). Fifty amps is half of the 100 A continuous rating, so a 100 Ah lithium battery passes the current test and fails the 110 Ah runtime test (Battle Born 100 Ah manual). Brushed motors on lithium should stay at 85% or speed 8.5 or lower (Minn Kota power article).
Lead-acid usable energy is about half the nameplate. To hold 110 Ah usable you need about 220 Ah of lead-acid nameplate, because 50% depth of discharge doubles the nameplate and a 100 Ah lithium battery is compared with a 200 Ah lead-acid bank (Battle Born chemistry guide). The manual's lithium battery is 100% usable, which is why the 110 Ah figure can be read as usable amp-hours on lithium and as a nameplate only if the chemistry allows it (Battle Born 100 Ah manual).
Parallel is optional runtime, not a voltage change. A second 12 V battery in parallel is how the help article adds hours (Minn Kota power article).
Breakers on the chart are 50 A or 60 A as listed per motor (Minn Kota battery chart). The accessory search on this page is a 60 amp breaker.
What size battery do I need for a 55 lb trolling motor?
One 12-volt battery rated at least 110 Ah. The 50/55 lb class draws a maximum of 50 amps at 12 volts, and thrust at or under 55 lb uses a single 12 V battery (Minn Kota battery chart; Minn Kota power article).
Does a 100 Ah lithium battery meet the 110 Ah guide?
It meets the current test and misses the runtime guide. 50 amps is inside a 100 amp continuous rating, and 100 Ah is below the 110 Ah recommendation for 6–8 hours (Battle Born 100 Ah manual; Minn Kota power article).
How does lead-acid compare at the same usable energy?