Dead Batteries

[Dubed]

Hi Guy,
I went out fishing Saturday. I steamed out about an hour to my fishing hole, set up for a drift, turned off motor and drifted about 20 minutes. Rinse and repeat a couple times. On my 3rd or 4th drift, motor would not start (battery dead).
I have a starting battery and a house battery wired to a 1/2/both/off switch. Both batteries were fully charged to start.
Switch was in the #1 position (starting battery). Electronics (two Helix 7s, and puck for trolling motor) are wired to the house battery with a seperate on/off switch controling them.
When boat wouldnt start, I figured no problem, I'll just switch over to the house battery or both position and start. Both batteries were dead.
Boat is wired like the picture shows. My question is, if one battery was bad could it drain the 2nd battery through the negative cable that is connected to both? I was surprised this happened and could really figure out how. I will pull both batteries today and have charged and load tested.
Any ideas?

 

[dingbat]

My question is, if one battery was bad could it drain the 2nd battery through the negative cable that is connected to both? I was surprised this happened and could really figure out how. I will pull both batteries today and have charged and load tested.
Any ideas?

No, they don't drain through the ground cable.
That is a butt load of power to use that quickly!!!!

Where and how is the second switch wired in to the system?

 

[Dubed]

No, they don't drain through the ground cable.
That is a butt load of power to use that quickly!!!!

Where and how is the second switch wired in to the system?

Thanks for your reply
I was thinking maybe if one had a bad cell or dead short, that connecting ground wire would transfer an issue.

The 2nd switch is just an on/off switch from my house battery to my electronics. Its a seperate wire from the pos terminal to the switch, from the switch to a accesory fuse panel, to my humminbirds. Ground from Neg post to bar, to humminbirds

 

[Scott Danforth]

how old are the batteries? have you had them load tested?

 

[Dubed]

I pulled a battery from my trolling motor and replaced my starting battery with it. I had zero issues the rest of the day

 

[Dubed]

how old are the batteries? have you had them load tested?

They are about 4 years old. They are being tested today. My original thought was a bad battery. But when they were both dead.....?

 

[Scott Danforth]

They are about 4 years old. They are being tested today. My original thought was a bad battery. But when they were both dead.....?

not uncommon for batteries to die about the same time.

 

[Dubed]

I will report back after they are load tested. I was just trying to understand if something could have caused it. When I charged them the night before (after sitting all week) the charger said they were at 95% when charge started

 

[airshot]

While I have had many batteries go well beyond 4 years, when it comes up to 3 plus years on a battery, I watch them carefully, any sign of a problem, time to replace them. While batteries are not cheap, being stuck miles out with no power isn't a good day in my book!! My own batteries are starting their 5th year with the exception of my house battery which I replaced last season. Trolling motor batteries and start batteries are on the clock but as of now stilll working well....knock on wood !!

 

[dingbat]

When I charged them the night before (after sitting all week) the charger said they were at 95% when charge started

Charger is looking at the rate of charge to determine capacity.

A dead battery, pulling very little charge, will register 95% full :

 

[Scott Danforth]

the battery in my truck load tested fine a month ago before a trip. a week ago, it was toast with an internal short. it was 47 months old.

 

[cyclops222]

I was ready to change a battery as it ran way down repeatedly.
I left the MANUAL Bilge Pump switch on for several days.
Oh well Can not fix stu.

 

[cyclops222]

I should not be surprised that it only lasted 5 ? years. At being not charged every day like a car battery is. Left unused every year from October To June 1 Is the fastest and best way to ruin a excellent battery.

 

[airshot]

I should not be surprised that it only lasted 5 ? years. At being not charged every day like a car battery is. Left unused every year from October To June 1 Is the fastest and best way to ruin a excellent battery.

That is why I keep mine on a maintainer over the off season...

 

[Dubed]

Update;
Both batteries are good and load tested fine.
Not sure what else could have caused the no start issue.
One thought is my charger is no good. Its says charged 100%, maybe its not? I would think that the alternator would have charged it after running for over an hour at cruising speed if that was the case. It did start right up at the dock on my way out. Also with selecting a, b, or both, I should have gotten something.
Only thing I changed this season was adding the on/off switch for my electronics, and installed a new slave solenoid for the starter. And like every Spring, I go through all connections and grounds and clean them up so their shiny.
Any other ideas?

 

[Dubed]

I'll also mention that Interstate said the cranking battery was still strong enough that it should have started the motor.
When trying to start, the engine would struggle to turn over slowly for a second, then click, click, click like a dead battery.
I swapped out for one of my new trolling motor batteries, and it fired right up.

 

[dingbat]

Update;
Both batteries are good and load tested fine.
Not sure what else could have caused the no start issue.

Any other ideas?

Typically the first symptom of a starter or solenoid failure

 

[Dubed]

Typically the first symptom of a starter or solenoid failure

Solenoid is new. I have a new starter on the shelf. Why would throwing another battery in fix the issue for the remainder of the day?

 

[dingbat]

Solenoid is new. I have a new starter on the shelf. Why would throwing another battery in fix the issue for the remainder of the day?

The first time the starter went out in the truck it started at the shopping center, no problem. Drove it home 15 minutes and it wouldn't start, battery at 12.4 volts.

Put the battery charger on it for 10 minutes and it started.
40 minutes later, no start again.

4 yro battery. Drove up to the parts store and had a new installed. Started right up. Next morning, no start again. 12.35V this time

I suspect it had something to do with bad spot in the commutator or brushes issues. Just needed a little extra oomph to get over the hump.

 

[airshot]

12.6 volts minimum is a full charge ! 12.4 is low but should start the engine, I would check the connections again and why would a new battery just installed, only have 12.35 volts after one start ?? What was battery voltage when installed ? Sounds like a battery with an internal short or a starter with the same.