More capacity is usually a good thing if one has the room, and can handle the extra weight.
Still, as far as how long they can power a trolling motor, one needs to know how much amperage draw that motor has, at whatever speeds they are using it at.
These linked 'wattmeters' will record:
While they will say 100 or 130 or 150 amp rating, these are maximum short burst ratings, not continuous
They are good for about 40 amps continuous, but the 12awg silicone insulated leads will get hot.https://www.amazon.com/T-Trees-Mete...mp;psc=1&refRID=72TCXNGSX3K7QHPHWK0Y
There are MANY clones of this same device with differrent prices, the above is just the first example I clicked to link. they only count to 65 amp hours. They are not 100% accurate and are not accurate below 0.5 amps. They are imperfect but a million times better than guessing.
These have a source and a load side. The source is the battery the motor is the load.
When charging the charger is the source and the battery is the load.
If one removed 50 amp hours from a battery it needs no less than 52.5 amp hours returned, and likely much more than that to be returned to full charge. The best AGMs say 105 to 112% returned tin order to reach full charge. Flooded usually have a much lower charge efficiency factor. and this CEF gets worse as the battery ages.
Anyway instead of guessing, you can see exactly how much amperage the motor draws, how much amp hours it is pulling from the battery, how low the voltage falls, how much the absolute highest amperage provided is. If you then reverse this wattmeter on your charging source you can see how much amp hours are returned to the battery.
This is another way to prove that most smart chargers stop well short of true full charge. If the charger does not return ~110% or more of what was removed on a marine flooded battery it is not fully charged.
Collect actual data.
I use 45 amp anderson powerpoles as my connectors on these wattmeters and replace the 12awg with 8awg. They easily handle 40 amps continuous and a pair of them has passed 180+ amps to start my v8 engine.
They do have versions that come with 8awg leads.
One could also hardwire an individual wattmeter into the load, and then one on the charging source wiring, rather than using connectors and just one unit..
So for ~30$ you can collect actual data. Once you realize that your charging sources are mocking you and prematurely killing your batteries, they will pay for themselves, if you restart the chargers over and over until the batteries reach closer to true full charge
Restarting automatic chargers successfully required dropping battery voltage to below 12.7 by applying a large load, then restarting charger, then removing the load that dropped voltage below 12.7v.
If you just unplug and reattach it it will see 13+ volts surface voltage, assume the battery is fully charged and goto float voltage.
Almost no charging occurs at float voltage, so one has to be smarter than their smart charger in order to get it to do its job.
I gave up on smart chargers for this reason and use an adjustable voltage power supply set to 14.7v and bring the battery to then hold it there there until I determine the battery is full, via amperage or with a hydrometer., at which point I lower voltage to float levels, or remove it completely.
One can also use a clamp on DC ammeter to determine how much amperage a motor is consuming under load. These are also wquiteuseful and about 32+$ or so, but they do not record amp hours or watt hours like the linked wattmeters above do. They are handy for other tasks though and good to have. Make sure it can do both AC and DC current. Many will say both but they mean it can read voltage ac or dc, but can only measure AC amperage, not DC.
The amperage the trolling motor draws in open air at a speed is not what it will draw when underwater pushing/pulling a boat so actual measurements in actual use are required. The wattmeters are not waterproof, but do not really get all that hot passing 40 amps continuous and could be put in a ziplock with some rubber bands.