Trolling Motor running out of battery on windy days

I was out on Pool 4 yesterday. It was very windy and I had to use the bow-mount MinnKota to keep my boat facing into the wind. I run a heavy, 17 ft. Alumacraft Trophy. I got over a nice spot where I knew there were fish and I was catching. The problem was that I had to make constant movements with the trolling motor just to stay vertical. I love the ability to do this, but it always runs my battery out in about 3-4 hours.

I have a 80pound thrust motor with two batteries to run it. The batteries are a couple years old but should be in good shape. I always charge them and, generally, take good care of them.

What I am wondering is: what do guys do to ensure that they always have enough juice for those “bad days” when they need to have the motor going constantly just to stay on fish? Do you carry an extra battery? Upgrade to the 101 pound thrust? Get better batteries?

I thought about throwing out a drift sock but I am sure that would have just led to constant tangles and headaches. Thanks for any thoughts.

I run the same boat with same lb thrust TM. I get way more than 3-4 hours out of it. In fact, I don’t think I’ve ever run out of juice in one day of fishing and I use it to troll quite often.

I’m not sure what your fix is, but this feedback should get you going on testing the battery’s and other components of the system.

ET

I also run the Minnkota 80# Terrova and get much more time than that. However, I will admit, when the boat was new, and had it plugged into a three-bank charger over the three months it was not used, I did not realize it would use up as much distilled water as it did. The tops of the cells were actually exposed. Of course, this weakened the batteries so that they would not hold a very long charge like you are explaining. Since then, the batteries are always conditioned and plugged in all the time with the proper amount of water inside and the batteries will last all day.

Check the liquid level inside and make sure they are conditioned. If not, it sounds like it might be time to replace.

Just as an FYI for all….Costco sells deep cycle batteries. With most companies, if the battery is weak, they will prorate you for a new battery. Costco does NOT. If for any reason the batteries do not seem to hold a proper charge before the warranty is expired, they will replace with a new battery at NO COST. Pretty good deal….just an fyi

I would test the batteries make sure you don’t have a dead cell in one or both batt.? Is it a 24v system? I guess is where I would start. I am looking at upgrading trolling motors and guys I am talking to say you will get the longer run times from a 24v system.

Sounds like it may be the batteries. I will check on them. Thanks.

Just to be clear, I had my finger on that thing and was moving up and down speeds and movement for a good two hours. That has to take a lot of juice. Plus I had the autopilot going just to stay vertical.

I have been in that spot with heavy wind, and current. You may not have the option…. but I will at times run a rear kicker as low as possible. Let the Trolling motor do half the work. Takes a little messing around, but when the TM is running at 7-10 to keep up with conditions, it will take a toll on batteries.

Certainly can get bigger batteries to get more hours.

There are also other things you can do to extend your trip.
Kicker motor is one of them.
Anchoring is another.
Drifting
etc etc

I guess my point is that if you want to rely hevily on your trolling motor for a fishing technique, understand that you can only do that for so long. Bigger batteries will extend that time. Dropping anchor instead of spot lock, back troll, etc. Sometimes you need to alter the fishing technique when you want to extend your time on the water.

3-4 years on a battery you can certainly expect performance loss.
I think i’m on year 3 or 4 on my batteries. Recently moved things around in the boat for more battery space and i’ll be replacing my 4 group 27’s this year (Even though they work good, they’re not year 1 good) with 4 group 31’s. I like my 3+day 24hr fishing trips. That requires a lot of juice. Interstate batteries for me. Never had an issue.

If you have only one weak battery ….get 2 new ones tho NEVER run one old and one new !

Not to sound like a smart arse here but have a dumb question to ask…

You do you have the 24V connected correctly so it pulls off both batteries vs 1 right?
I didn’t have mine connected correctly once and was only pulling from 1 battery and drained it pretty quick

what size batteries are you running….. group 24 compared to group 29 is a huge difference on run time…..

group 24 would be a smaller battery…..(run time)
group 27 would be a min sixed battery
group 29 (or 31) would be a large battery

I had the same issue on my 24v terrova when I had it. Got my batteries tested and I had one with a bad cell. System was basically running on one battery.

Replace your batteries!!!! The best available are odyssey but are about 300 a piece. Worth every penny 3 year warranty. Also buy the biggest you can fit in your boat. I can run my 101 all day and still have a day or two worth of battery.

on a 24 volt system you need to run a jumper cable across pos to neg to get 24volts look up a diagram online to reference this. If they are tied together you might be running 12 volt in parallel.

Are you using an on-board charger?I ran a 24 volt system without an on-board charger for a few months when I upgraded to a 24v and had the same problems. Once I got the on-board charger installed the runtime more than trippled. Having the batteries charged to the same level made a big difference for me.

I just hook up a smart charger to each 12v battery, which are hooked up in series to make 24v.
Charges each battery to 14v

I don’t see where you explicitly state what model TM you are running.
The newer models have smarter circuitry to extend battery life.
how old is it?

I was having a similar problem and thought I needed a new battery. It wasn’t the battery but rather a bad connection. From constantly disconnecting the cable from the battery half the wires had frayed on the end and I didn’t notice it soon enough. Cut it back and redid it and I now have all day power again with the same battery I was going replace a year ago.

Besides checking the batteries and cleaning the connections I would also check the wire size in your boat to make sure it has sufficient current-carrying ability. Your 80# thrust TM draws about 60 amps at max speed. You have about a 40′ long circuit if the batteries are in the back of the boat. The Ancor Marine catalog says #6 AWG wire would give a 10% voltage drop and a size #1 AWG wire would be required for to reduce the drop to only 3%. So check that you have at least size #6 AWG wiring (larger AWG # means smaller diameter and more resistance) in the boat. I just upgraded to a new TM with more thrust and had to pull new #4 AWG wire to handle the larger current as my boat only had size #8 AWG wire when built. The wire AWG size should be marked every few feet on the wires in your boat.

Sorry, looked at the wrong chart. You need at least a size #8 AWG wiring for a 10% voltage drop with a 24 volt system. A #4 AWG system would give you a 3% drop. So at least a size #8 AWG.

Are the batteries for the trolling motor only? It does not work to use starting battery as one of the batteries. You must dedicate 2 batteries to a 24volt system nothing else hooked to them. You must recharge every time they are used even if it only for an hour. Check fluid 2 or 3 times a season only use distilled water to top off. Bringing an extra battery and exchanging one of the batteries will only ruin the new battery. If a cell goes bad on one battery which can cause issue like you are having it degrade both batteries and you must replace both. I had a 18 ft princraft with 115hp and windshield and a Minnkota 80 Terrova and could pull bottom bouncers into a heavy wind for a full 8 hour day or longer. If using the anchor lock or intermittently controlling the speed it would last longer. I usual got 4 full season out of Interstate 29 series deep cycle and changed them the 5th year whether they needed to or not. I will not waste a day due to bad batteries..
Let us know what you find out

Mwal

80 pound Terrova and 2 size 30 AGM batteries dedicated to only that electric motor…run all day and more in the river.

I believe this approximation may help clarify things on trolling motor loads vs. battery capacity.
Use this for example: A given size 31, Marine Deep Cycle 12 Vdc Battery is used to Power a trolling motor that draws 55 amps at max trust. The battery is rated at 108 amp hours (a standard battery parameter). The motor can then run for (108 ah / 55 Amps = time) → 1.96 Hours. Before the battery drops below ~ 10.5 Vdc.

PJMulvihill wrote:

Sorry, looked at the wrong chart. You need at least a size #8 AWG wiring for a 10% voltage drop with a 24 volt system. A #4 AWG system would give you a 3% drop. So at least a size #8 AWG.

Beat me to it. Additionally to the batteries, check that the appropriate wire size was used.

If you run the main engine between fishing holes check out the Trollbridge24, it charges the 24 volt battery from your 12 volt alternator.

if your big motor puts out enough amps, i belive the main battery has to reach full charge to start charging the other 2 bat.so if you’re not running far enough it doesn’t do much good.
Stan