Advantage of New/Bigger Batteries

[Kwasham]

Will newer or bigger batteries increase the power of a trolling motor or just increase the battery life?

[CatFan]

Just battery run time and life. Power is the same.

[Kwasham]

So switching from a Group 27 to a Group 29 or 31 wouldn't have an affect on the output/power of the TM, just the battery life?

[rocket man]

Battery life or Run time. Power the same.

[Kwasham]

Battery life or Run time. Power the same.

Over the course of the battery life, will the power diminish? For example, when the batteries only has 20% charge will the trolling motor set on 10 have the same power as if the batteries had 100% charge?

[bigfishsmallcamera]

Over the course of the battery life, will the power diminish? For example, when the batteries only has 20% charge will the trolling motor set on 10 have the same power as if the batteries had 100% charge?

As the battery runs down, it will not provide as many volts, thusly the motor won't be running as powerful. Have you noticed when the batteries are starting to die, your electronics are not performing as well?

[CatFan]

So switching from a Group 27 to a Group 29 or 31 wouldn't have an affect on the output/power of the TM, just the battery life?

Right. And I think you are confusing the terms battery life and run time. Battery life is how long until you need to replace them. Run time is how long you can fish in a day.

[Lou r Pitcher]

As the battery runs down, it will not provide as many volts, thusly the motor won't be running as powerful. Have you noticed when the batteries are starting to die, your electronics are not performing as well?

Yes, however the discharge voltage curve of a lead acid is very non-linear.....if you are waiting until the TM noticeably slows down ("starting to die"), the battery is being overly discharged.

The power (top speed) of the trolling motor throughout the "safe discharge" of the battery is reasonably constant (the flatter part of the voltage curve) .

[Kwasham]

As the battery runs down, it will not provide as many volts, thusly the motor won't be running as powerful. Have you noticed when the batteries are starting to die, your electronics are not performing as well?

When I first put in in the mornings I can run on 4 or 5 and cover water at a good speed but after running the TM for about 3 hours or so I end up having to crank it up to 7 or 8 to get the same type of speed out of the TM. Batteries are 4 year old Everstarts that stay on the charger when not in use.

[bigfishsmallcamera]

Yes, however the discharge voltage curve of a lead acid is very non-linear.....if you are waiting until the TM noticeably slows down ("starting to die"), the battery is being overly discharged.

The power (top speed) of the trolling motor throughout the "safe discharge" of the battery is reasonably constant (the flatter part of the voltage curve) .

I agree with these statements

[billnorman1]

With a larger capacity battery, you will have more power longer. This is with a typical lead-acid or AGM battery. A Lithium, Nickel-Cadmium, or other specialized cell delivers its voltage, under load, at a constant value until failure. A Lead Acid has a downward slope to its voltage as its reserve is diminished.
A newer battery will be more efficient. If you got the money, buy new and big.

[catdude28]

When I first put in in the mornings I can run on 4 or 5 and cover water at a good speed but after running the TM for about 3 hours or so I end up having to crank it up to 7 or 8 to get the same type of speed out of the TM. Batteries are 4 year old Everstarts that stay on the charger when not in use.

It sounds like your batteries are at the end of their life. Get new ones. 4 years is pretty good for wet batteries.

[Skunked again]

It sounds like your batteries are at the end of their life. Get new ones. 4 years is pretty good for wet batteries.

^^ What he said ^^