Odd trolling batt issues

[JOEALLY]

My new to me boat has a 24V MG 80# troller with 2 batteries in the front center box in front of the cooler.

I have the stealth charger and an optima cranking battery.

Odd issue today which is the first time I've fished in it for over an hour.

I'm wondering if anyone has encountered it - thinking maybe it's something simple.

Last Saturday, I plugged in my on board stealth charger and a few hours later the lights turned green so I unplugged it.

The boat sat all week in my garage with the master switch off.

This morning, my son & I launched below a lock & dam that was sending water downstream pretty good. We ran 5 miles to the lock and fished about 3 hours. I had the troller on 7-8 most of the time & on high (9) some of the time. The stealth gauge at the bow show 24.4 volts and motor ran strong.

I made about a 10 mile run down river, dropped the troller, it showed 24.4 but within a minute it started dropping to 18.7 and stayed there.

I made several more runs and each time when I dropped the troller, it would show 24+ but within a minute drop to 17.8-19 volts. It never actually quit & never dropped lower than 17.8, I used it like that for a couple of hours but it was definitely running on lower power.

Both trolling batteries have the indicator "green" is good - both show green.

I'll admit I've been out of the loop using a trolling motor the last few years but I just found it odd that it would drop immediately then not drop anymore.

The trolling motor plus was plugged in all week, any chance it drained the batteries enough that 3 hours pulled the batteries down this morning from 24V?

But, wouldn't a 10 minute run on the engine charge the batteries some? It appeared to as each time I shut down it showed 24+ volts.

Any ideas? Battery going bad, issue with stealth, weak resistor, etc????

I will also add that at idle, my smartcraft showed 12.8-12.9 volts and once on plane it would fluctuate between 13.2-13.8 but normally stayed about 13.5 running about 4000 rpms.

[NOTGSXR]

Maybe Johnny Maxwell sold you a lemon!

[JOEALLY]

Maybe Johnny Maxwell sold you a lemon!

Ha! I'm thinking I've got a weak trolling battery but I'll investigate.

I did run it 82.8 mph today with me and my son, full gas, full livewell and our tournament load (medium). I think I was about 5700-5800 rpms, still getting the feel of it as it's been about 5 years since I've driven an Allison. I bumped the trim a couple more times but it didn't pick up speed. I think my propshaft was set about 1/4" below the pad if I remember correctly.

[CatFan]

24.4V would indicate a serious battery issue. 13.1V per battery or 26.2 for the pair is full variety.

[JOEALLY]

24.4V would indicate a serious battery issue. 13.1V per battery or 26.2 for the pair is full variety.

You are absolutely correct. I really didn't even think about that until you posted.

I did notice after one of the 10 -15 minute runs with the big engine the stealth gauge showed 26.2 when I dropped the trolling motor but it dropped within a minute.

Hopefully, I just have a bad battery - that's the easiest fix!

[fishnfireman]

Sounds like one of the batteries is bad.
The stealth would get it back as best it could while you were moving .. but soon as you drew some power it went flat.
Have seen many times the charger will show them to be OK when there not. have them load tested by someone who you trust.

[JOEALLY]

Sounds like one of the batteries is bad.
The stealth would get it back as best it could while you were moving .. but soon as you drew some power it went flat.
Have seen many times the charger will show them to be OK when there not. have them load tested by someone who you trust.

Thanks, this is what I plan to do.

The charger (Stealth) has been plugged in for about 4 hours this afternoon, the lights are still red.

[CatFan]

Thanks, this is what I plan to do.

The charger (Stealth) has been plugged in for about 4 hours this afternoon, the lights are still red.

Load testing isn't going to be helpful. At least one battery isn't reaching full charge. Measure the voltage on each battery when the charger indicates charging is complete.

[JOEALLY]

I do plan to check the voltage after they are charged.

The batteries are AC Delco Voyagers. There is a M 123R code which I'm guessing may mean December 2013.

[CatFan]

I do plan to check the voltage after they are charged.

The batteries are AC Delco Voyagers. There is a M 123R code which I'm guessing may mean December 2013.

If they are Johnson Controls batteries (angled corner vent caps) they'd have a code that started with a number. If Exide, code would be 6 digits.

[Tim Powell]

With the troller on 7-8 it would not take long to drain the batteries, especially if they are smaller than a group 31. You might have a bad battery but I'd bet you could have drained them as well.


With that same troller I have drained 2 optima's in 2-3 hours running on 6 to hold steady in current and 7-8 to slowly move forward.

[fishnfireman]

Load testing isn't going to be helpful. At least one battery isn't reaching full charge. Measure the voltage on each battery when the charger indicates charging is complete.

When done correctly load testing is the way to go..
Have seen more than once after (charging was complete) that voltage would show to be good. A better voltage test would be to test soon after putting a load on the batteries--At this point the bad battery will show to be a lot lower than the good one..
If they were my batteries, I would replace both--Odds are if you replace one the second wont be far behind.
I use mine hard and 2 years is about the end for me.

[JOEALLY]

If they are Johnson Controls batteries (angled corner vent caps) they'd have a code that started with a number. If Exide, code would be 6 digits.

I'll pull them out today so I can get better information, kind of hard to see in the boat.

It looks like angled vent caps.

I can see the model number is M27MF and beside it is 1981044. There also a 5 digit number 56707 if I remember right close to the tag that has M 123R. So basically I have no idea

[av]

I would recommend replacing the in line breakers on the Stealth they start to have to much resistance over time from moisture , I always kept two spares on hand ... also not sure if it is an issue but I always kept the Stealth plugged in till time to pull it out of the garage.

[JOEALLY]

With the troller on 7-8 it would not take long to drain the batteries, especially if they are smaller than a group 31. You might have a bad battery but I'd bet you could have drained them as well.


With that same troller I have drained 2 optima's in 2-3 hours running on 6 to hold steady in current and 7-8 to slowly move forward.

I guess this is possible for sure. The stealth charged all night before giving two green lights. I was showing 27v on the stealth gauge after I unplugged it this morning. I'm going to let them settle today and check individual voltage this afternoon.

We were fishing behind the end of a lock wall so some of the time we were in the hard current and some it would wash us back around into the eddy so I can't say it was on constant like it is when fishing behind a discharge but it was a pretty steady use.

They are group 27s. (M27MF)

The reason I didn't think it was simply drained from useage is even after a few 10-15 min runs, the voltage would show 24 & quickly drop to 18. Maybe that's not long enough for the engine to really charge them. With the stealth AC is has to top off the crank battery before dumping to the trolling batteries correct? I was running the livewell and the 2 little lowrance 5s on the crank battery the whole time as well so maybe the crank battery needed juice.

[JOEALLY]

I ran the trolling motor for a few minutes to put a little load on the batteries this afternoon after charging all night.

The batteries show 12.7 & 12.8 V with a meter.

[shuddyssoup]

If you call Danny at Stealth One he will walk you through any issues. He's helped me more than once and is a patient man. I am on my second stealth ( first one was fine but not hot enough for AGM's so Danny gave me a trade in allowance and sent me a new D.C. charger ) and will be taking the charger out of my Allison and installing it in my Nitro. I fish river current a lot and used to eat batteries in a few short hours. Not anymore. Good luck with your issue.

[CatFan]

I ran the trolling motor for a few minutes to put a little load on the batteries this afternoon after charging all night.

The batteries show 12.7 & 12.8 V with a meter.

Give them some time to set. Still showing some surface charge, but a tenth of a volt difference is probably a sign of a problem.

[fishnfireman]

Load test Surface charge still showing.
If nothing else carefully run the trolling motor for a spell in your garage then check the batteries individually. odds are if there is a bad battery it will soon show itself..

[JOEALLY]

So, after sitting all night (without charger plugged in), the batts now show 13.10 & 13.11 with a meter.

I've let the trolling motor run a few minutes, will it hurt it to turn it on "constant on" and let it run for an hour or so? I'm assuming the motor is cooled by the housing being underwater so I didn't know if it would build too much heat running dry.

I do plan to load test when I can get to it just to see what it shows.