deep cycle battery life?

[newpike]

I have a 30lb Minnkota trolling motor on a 12ft jonboat. Fleet farm battery. All items about 2 to 2 1/2 years old. All bought new. Battery started to go last fall. Now using the 40lb Minnkota Maxx motor. Battery on lasts about an hour or two. How long do these batteries last?. I go about 6 days a season. Three to six hours a time. Thanks.

[katoguy]

What group battery and amp hour rating?

I recommend a group 27, which will probably be rated at least with 105 amp hour rating.

105 amps times .85 (usuable amps) = 89 usable amps / 30 (max amp draw of Endura 30) = 3 hour running time at high speed

(if battery is in good shape - fully charged by a good charger)

[Northlander]

3-4 years is about norm on a trolling motor battery if taken care of.

You should get about 3-10 hours of actual trolling time depending on how high you are having to run your motor and the quality of your battery and how well you charge it.

[katoguy]

newpike, I see you edited to a Max40T. This motor draws 42 amps on high speed.

[newpike]

Talked to an electrical engineer and he did not buy the Digital Maximizer thing. I still hope its more efficient. As far as amp draw I don't get it. I now draw a little more, but have 10 lbs more thrust. ?? Use more energy but get farther faster. I think the battery is toast. I think I will try a similar battery and see how it goes for a season or two. What I know is the motor is similar to my old one in many aspects but much more efficient. A fresh battery will tell. Now need to find a deal on a battery. Sears,Walmart,Fleet ? Thanks.

[RainyEye]

my last deep cycle was from Wal mart, but mine is now dying and it's 4 yrs.old. I thought I would get a little more life out of it.

[Nick Kuhn]

<---- is an electrical engineer...

With batteries every time you charge them they hold less and less total charge. A few things that help the overall life:

1. Don't charge the battery until it's nearly dead (this may not always be an option).

2. Take the charger off as soon as the battery is full. Good chargers can help here but you are still heating the battery some. Heat greatly accelerates aging, so you want to minimize it when possible.

3. Run the motor as slowly as possible. First you won't draw nearly as much current and second you will avoid heating the battery again. DC electric motors tend to be least efficient at their highest speeds.

I can get upwards of 30 hours of lake time out of my trolling motor battery, just being smart about boat control and how the trolling motor is used.