Why are my boat batteries dying so fast?

[Caiden24]

I do fishing tournaments so my batteries lasting long is important to me, and I have a nationals tournament for high school this Wednesday and my boat batteries are hardly lasting 5 hours. I have 3 12v interstate deep cycle batteries 1 for cranking battery and my fish finders and 2 ran in series to make 24 volts for our 24 volt trolling motor. I just don't know why they aren't lasting long when they are both just for a trolling motor. I have seen professionals and there batteries lasting them all day on the water perfectly fine with no problem. How can I make mine run longer and work for a 24v motor, I have heard of like running them in parallel, but would that work for a 24v trolling motor? Thanks! 

[MN Fisher]

14 minutes ago, Caiden24 said:

How can I make mine run longer and work for a 24v motor, I have heard of like running them in parallel, but would that work for a 24v trolling motor? Thanks! 

1: What's the AH rating on those batteries

2: No - connecting in parallel won't run a 24v TM - you'll get double the AH, but only 12v

3: Are they the exact same model and were they purchased at the same time?

4: How old are they, and have they been maintained properly - charge as soon as you get home, don't wait until a day or two before you're going to use them.

5: How often have you 'drained' them totally - dropping the charge below 50% repeatedly will damage lead-acid batteries.

[Caiden24]

1 minute ago, MN Fisher said:

1: What's the AH rating on those batteries

2: No - connecting in parallel won't run a 24v TM - you'll get double the AH, but only 12v

3: Are they the exact same model and were they purchased at the same time?

4: How old are they, and have they been maintained properly - charge as soon as you get home, don't wait until a day or two before you're going to use them.

5: How often have you 'drained' them totally - dropping the charge below 50% repeatedly will damage lead-acid batteries.

ok, My dad said they are brand new and were purchased 1 month ago and they are the same model. I mean we don't go fishing everyday so no we do wait a couple of days before using the boat, but we do charge them as soon as we get home. We have been on the boat with the new batteries probably 10 times and I think we have dropped them below that every time. The AH rating on the batteries are 81.

I attached a photo that tells about the batteries more, idk that much about batteries. Thanks for the help!

 

[MN Fisher]

6 minutes ago, Caiden24 said:

I attached a photo that tells about the batteries more, idk that much about batteries. Thanks for the help!

What trolling motor are you using with those?

[Choporoz]

Return them?  I have run a 24V trolling motor for four days (without charging) on Interstate batteries. Or, I suppose, you may have an electrical problem...or a charger problem?

https://anchor.travel/why-does-my-trolling-motor-battery-die-so-fast/

[Caiden24]

5 minutes ago, MN Fisher said:

What trolling motor are you using with those?

just a basic motorguide with 70 lbs thrust nothing special

6 minutes ago, Choporoz said:

Return them?  I have run a 24V trolling motor for four days (without charging) on Interstate batteries. Or, I suppose, you may have an electrical problem...or a charger problem?

https://anchor.travel/why-does-my-trolling-motor-battery-die-so-fast/

oh, The problem is, we bought these in washington because that's where I live but I am in Wisconsin right now for my national tournament. Are the batteries you have lithium batteries? Thanks!

[MN Fisher]

How fast you running it on average?

 

This is from the spec-sheet based on 100ah batteries.

• 20 Hours: At slow, trolling speeds that draw 5 amps or less
• 4.8 Hours: Approx. run time with throttle 50% open
• 2.4 Hours: Approx. run time with the motor at full throttle

 

The 70# Motorguide draws 42 amps at max, 24 amps at 50% - with 81ah batteries, you wouldn't get even 2 hours at max, just over 3 hours at 50% throttle.

[Caiden24]

2 minutes ago, MN Fisher said:

How fast you running it on average?

 

This is from the spec-sheet based on 100ah batteries.

• 20 Hours: At slow, trolling speeds that draw 5 amps or less
• 4.8 Hours: Approx. run time with throttle 50% open
• 2.4 Hours: Approx. run time with the motor at full throttle

 

The 70# Motorguide draws 42 amps at max, 24 amps at 50% - with 81ah batteries, you wouldn't get even 2 hours at max, just over 3 hours at 50% throttle.

oh that's where my problem is, I mean I run it at 1 speed in turtle mode, not sure what percent that is. But sometimes to get out of stuff or to fight wind, we will turn it up. 

[MN Fisher]

8 minutes ago, Caiden24 said:

1 speed in turtle mode,

That's 'slow' - 5amp draw, 16 hours on your batteries if you never went faster...8 hours if you don't go below 50% charge.

[Bird]

Yeah something ain't right.

I have (2) group 27  interstate batteries on a 24v 70lb motorguide.

Wife and I fished 5-6 hrs per day for 7 days without a recharge........ only because we were in a remote location and had no way of recharging.

This was a rare occasion but we had trolling motor the entire time.

 

 

 

[Caiden24]

15 minutes ago, MN Fisher said:

That's 'slow' - 5amp draw, 16 hours on your batteries if you never went faster...8 hours if you don't go below 50% charge.

yeah, We go faster with different water conditions but with 2 batteries hooked together, It should be going longer.

6 minutes ago, Bird said:

Yeah something ain't right.

I have (2) group 27  interstate batteries on a 24v 70lb motorguide.

Wife and I fished 5-6 hrs per day for 7 days without a recharge........ only because we were in a remote location and had no way of recharging.

This was a rare occasion but we had trolling motor the entire time.

 

 

 

I have group 24 so idk how much of a difference that makes, Our motors are the same though. This doesn't make sense, I mean we have a 21 foot boat idk if that would change it a lot.

[Tennessee Boy]

Somethings definitely ain’t right.  I’ve measured the current draw on my 80lb Ultrex.  The current draw goes up exponentially as you increase the speed.   I draw 41 amps on 10,  8 amps on 5,  and 1/2 an amp on 1.  You should be able to go for days on a charge under normal fishing conditions.  
 

If the problem started with the new batteries then I would return them.  If you’ve never gotten good performance then it could be something wrong with the TM or possibly even the wiring.   Could also be your charger is not fully charging the batteries.  

[gim]

23 minutes ago, Caiden24 said:

I have group 24 so idk how much of a difference that makes, Our motors are the same though. This doesn't make sense, I mean we have a 21 foot boat idk if that would change it a lot.

I assume your boat is a 21 foot fiberglass bass boat. That is an under powered thrust for such a heavy boat, plus the smallest size batteries. Even so, there’s something wrong. You should get more than a few hours out of them if they are fully charged.

 

I would upgrade those batteries to at least a size 27 or 31 if they’ll fit, and consider going with a more powerful bow mount.

[Caiden24]

27 minutes ago, Tennessee Boy said:

Somethings definitely ain’t right.  I’ve measured the current draw on my 80lb Ultrex.  The current draw goes up exponentially as you increase the speed.   I draw 41 amps on 10,  8 amps on 5,  and 1/2 an amp on 1.  You should be able to go for days on a charge under normal fishing conditions.  
 

If the problem started with the new batteries then I would return them.  If you’ve never gotten good performance then it could be something wrong with the TM or possibly even the wiring.   Could also be your charger is not fully charging the batteries.  

yeah, I think it could be our batteries. We haven't tried using different ones because we got these when my dad bought this boat. So it could be them.

11 minutes ago, gimruis said:

I assume your boat is a 21 foot fiberglass bass boat. That is an under powered thrust for such a heavy boat, plus the smallest size batteries. Even so, there’s something wrong. You should get more than a few hours out of them if they are fully charged.

 

I would upgrade those batteries to at least a size 27 or 31 if they’ll fit, and consider going with a more powerful bow mount.

Alright, The funny thing is. We had a big trolling motor but my dad sold it because it was "To big". And yeah it is 21 foot fiberglass. I will have to just suffer until we get back I guess. Unless there is something I can do while I am here. Maybe if there is a frayed wire. I can try looking tomorrow for fraying. 

[MN Fisher]

8 minutes ago, Caiden24 said:

Maybe if there is a frayed wire. I can try looking tomorrow for fraying. 

Cheap multimeter that measures Ohms (resistance)

Length of known good wire (buy fresh?)

Disconnect batteries.

 

Connect wire length between far end of run and positive on meter. Connect near end of run to negative. Should read 0 (zero) or close to it. If it reads high, there's an issue with that run.

[Caiden24]

3 minutes ago, MN Fisher said:

Cheap multimeter that measures Ohms (resistance)

Length of known good wire (buy fresh?)

Disconnect batteries.

 

Connect wire length between far end of run and positive on meter. Connect near end of run to negative. Should read 0 (zero) or close to it. If it reads high, there's an issue with that run.

alright, I can definitely test that. I don't think that would be a to long of a fix. and my dad does construction so I am sure he knows how to test that, There is a Ace hardware near our place we are staying so I can see if they have one. So I need to disconnect them out of their series to do that right? Thanks!

[MN Fisher]

11 minutes ago, Caiden24 said:

So I need to disconnect them out of their series to do that right? Thanks!

Just disconnect the main cables from the pair to the TM - remove the batteries out of the circuit...don't have to separate the batteries themselves.

[Caiden24]

3 minutes ago, MN Fisher said:

Just disconnect the main cables from the pair to the TM - remove the batteries out of the circuit...don't have to separate the batteries themselves.

alright, its late here so I will have to check that tomorrow. This seems like best case scenario because it seems like an easy fix.

[MN Fisher]

3 minutes ago, Caiden24 said:

seems like an easy fix.

It's not a 'fix' - it's just diagnostics to make sure your wiring is okay.

[Chris Catignani]

What kind of charge are you putting on the battery? (amps per battery).

Also...check you fluid level.

[Jig Man]

It looks like you have a corroded terminal.  Besides that you don’t have near enough battery.  You need way more rc than 140.

[WIGuide]

The pro's you're seeing running all day on their batteries are using bigger batteries. Group 24 series are about the smallest used for a trolling motor and you'd see those on something like a jon boat. The group size is the physical size of the battery and most bass boats would be running a minimum of 27 series and many run group 31's. I would think they'd run a little longer, but maybe not. Since you're in La Crosse, go to Team Marine. The guy that owns it is a good guy and will get you back on the water where you can actually fish a full day. If it's a battery issue, Interstate batteries are sold all over here and they should be able to warranty them if needed. You might have to buy a couple batteries, but it would really be terrible to come all this way and not even be able to put a full day on the water in the National Championship. 

[Caiden24]

3 hours ago, WIGuide said:

The pro's you're seeing running all day on their batteries are using bigger batteries. Group 24 series are about the smallest used for a trolling motor and you'd see those on something like a jon boat. The group size is the physical size of the battery and most bass boats would be running a minimum of 27 series and many run group 31's. I would think they'd run a little longer, but maybe not. Since you're in La Crosse, go to Team Marine. The guy that owns it is a good guy and will get you back on the water where you can actually fish a full day. If it's a battery issue, Interstate batteries are sold all over here and they should be able to warranty them if needed. You might have to buy a couple batteries, but it would really be terrible to come all this way and not even be able to put a full day on the water in the National Championship. 

Alright, thanks for the help. I will try and go check them out. 

[@reelChris]

Those don't look like new batteries.  And, they are definitely the wrong size for the application.  Old, undersized batteries are not going to last very long on a trolling motor pulling a heavy boat.

 

 

[Capt Ed]

Congratulations to you for fishing in high school tournaments and kudos to your dad for supporting your passion.

 

As you've pointed out, your fishing success is directly related to the reliability and performance of your equipment.  Whether it's your rod and reels, tow vehicle, boat and engine, electronics, or your trolling motor and batteries, etc., selection and maintenance of your gear is critical to enable you to do your best when competing.  

 

Lots of good suggestions have already been made and after you solve the current problem, I suggest an internet search for;  1.  Selecting the best tm batteries size and type that meet your needs, 2.  Marine battery maintenance, for long life and peak performance  and 3.  How to select and use the right charger for optimal results.  

 

Best of luck in your fishing tournament!