Battery Discharging....

xpress19

Member
Sometimes when I really lean on my Fortrex 80. I come home and notice the battery closest to the front will be charged and the battery at the back of the boat will be dead. I have a three bank charger.. Any ideas??????
 

djsmarinelectronics

Active member
How are you two trolling motor batteries wired? positive to positive or positive to negative?
 

Skeets

New member
I would suggest you swap the troll batteries position to see if it's just the one battery. This way you can tell if your charger has a bad bank that is not working. If you swap the batteries and then the same one goes dead you know you need to replace it.
 

river rat

New member
If they are both for the trolling motor why is one in the front and one in the back? That could cause it to pull more from one than the other because of the length and size of the wire
 

catch 1

Member
Get a volt meter and check the output to each battery with the charger on. Each bank should be fused did you check the fuses? Are both batteries the same size and age?
 

chillerman69

New member
catch 1 - 11/14/2015 9:03 AM

Get a volt meter and check the output to each battery with the charger on. Each bank should be fused did you check the fuses? Are both batteries the same size and age?

Pretty much agree with catch1 Everyone must have a meter unless they live in a cardboard box. Each + lead going to T/M should have a fuse. Check both. If both aren't fused, drop back and take care of that first. A 24V T/M will run on 12V's but only about half speed, however the Fortrex controls are designed for 24V's and may/should just sit there waiting on another 12V's before operating, never tried it. I also advise against running on 1/2 voltage unless you have no choice.

Smart Chargers are too smart sometimes and see battery death long before it happens. Check the fuses on charger leads. Not sure what kind you have and how it'll act if one is blown

Swapping batteries around could reveal something but are heavy and a meter should be able to find any issue that swapping batteries would show you

Verify all mechanical connections are clean. Re-make any crimped connection if fuses and batteries all test good. You really can't be 100% sure on a crimped connection, just by looking or wiggling it. I solder/shrink tube everything because marine conditions and crimped connections just don't make sense to my pea brain...unless circumstances require it for temporary fix.

Different length leads on the batteries will draw differently as RR stated but shouldn't cause your issue but it does mess with my mind. I'm sure (I hope) lack of room or boat balance made the bow/stern setup necessary.

Good luck and the more details the better, if you still have issues
 

jsb

New member
I had a similar situation just a while back. My voltage looked good and they both seem to be getting a full charge. It turned out that one of the battery wasn't holding the amperage. First I would make sure it's wired correctly and check the connections all are tight and clean like everyone has said. If you don't have it fused then put one on it. My suggestion is don't put a fuse but put a circuit breaker. Much easier if it blows you don't have to find a fuse and ect. Just wait a minute to let it cool off and poke the button and go. If everything looks ok then take to a parts store or somewhere that can do a load test.
 

digitalcb

Member
A battery load tester is a great tool to have.</p>

$22 at Harbor Frt and $22 Amazon Prime
</p>
 

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