# Starting Battery Issues



## Meerkat (Aug 10, 2008)

I am having problems with my starting battery going flat and am looking for ideas. My first thought was the battery was bad but I have had the battery load tested and it is fine (least that is what Autozone tells me).

I have an onboard charger connected to the battery. Charge it up overnight and it shows fully charged. Put the boat in the water, run out to where I am going to fish. Shut down the main motor & switch to the Minn Kota (totally separate batteries and circuit) & gas kicker. Starter battery is running the radio, an hds 5, an Elite 7 & the livewell pump. After 5 or 6 hours trolling try to start the main motor & the starter battery is flat. Jump it from the trolling batteries and we are back in business but the dash voltmeter is showing only 10 volts. After a while it crawls back up to about 14 volts.

So I am figuring maybe a short or stray current so I hooked up an ammeter in the circuit and turned on everything that the battery powers and it draws 2 amps. The battery has a reserve capacity of 150 hours (1 amp for 150 hours = 150 hours reserve capacity) so at a 2 amp draw the battery should run for 75 hours!

So here is what I am planning. I have the boat in the garage now with a fully charged battery (via the onboard charger). I have shut off the charger and master switch (so there is no load on the battery) & will see if it discharges by itself. Then I will try it with everything on that the battery normally powers and see how long it takes for the battery to run down. Then I will repeat the process with a different charger to see if the onboard charger is not charging properly.

I will also run the main motor on muffs and check the charging circuit but I don't think that is the problem as the battery showed fully charged when I went out yesterday & I only ran for 15 minutes before I shut it off and started fishing so even if the charging circuit on the motor was not working the battery should still have had plenty of juice left?

Any additional ideas? Your input would be most welcome as I am baffled. I have had the boat 5 years and never had this problem before...


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## G.lock (Apr 1, 2014)

I ran all electronics off my trolling batteries. The cranking battery was just that a fast discharge high output cranking battery, it didn't like the long slow discharge that hours of use as a power source would put on it.


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## fishdealer04 (Aug 27, 2006)

Is it possible that the electronics are draining the battery too much for it to crank the main engine? I have a Mercury OptiMax Pro XS and its supposed to have 1000CCA to start the engine. From a lot of forums that I have read people were having trouble with their Opti's not starting after fishing for awhile due to the electronics being hooked up to the same starting battery and it did not have enough CCA to start the main engine. Since you have had your boat for 5 years and never experienced this before it seems weird unless the battery is finally starting to die?


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## meats52 (Jul 23, 2014)

Did you check your starter. I had a car years ago that had a short in the starter and it would drain the battery when the engine wasn't running. If you have been using this setup for five years and the battery tested good then I wouldn't think your electronics are draining the battery. Your next trip out when you shutoff the motor disconnect the positive cable from the starter until you are ready to start the motor then hook it back up and see if the motor starts.


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## bountyhunter (Apr 28, 2004)

my moneis on your battery, its got a weak cell. they don,t like to exchange batteries, charge the battery and have it load tested some other shop.


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## Meerkat (Aug 10, 2008)

Thanks for the ideas guys! 

Fishdealer & Bountyhunter - I have had the boat for 5 years but the battery was replaced 2 years ago. But even though it tested good I am inclined to suspect the battery. I am thinking I have a new battery in my truck so I may put that in the boat, hook it up, switch on all the electronics and see if it drains the truck battery too.

Meats52 - I put a multimeter in the circuit to check for parasitic currents (like a shorted starter) & there was nothing except a very small 0.012 amp draw with everything switched off. So I am going to try to track that down by disconnecting everything in sequence. 

But when I checked for stray current, the boat is not in the water, it is on the trailer in my garage & I am thinking maybe I need to ground the boat and then try it again.

G.lock - did you have any interference problems running your electronics off the trolling motor batteries? Like the radio & the fishfinders/chartplotters? I have heard that can be a problem so I only have my trolling motor on the trolling motor batteries and everything else is on my starter battery (dual purpose). Maybe I need to change that?

Also I am going to put the motor on muffs and run it to check that it is charging the battery. Even though last time out I started with a fully charged battery and hardly ran the main motor.

And I have a mess of wires for each instrument, pump, etc. all hooked directly to the battery terminals. It was that way when I got the boat. Anyone know of a decent buss bar system for small boats so I can organize the wires while I am fixing this issue?

Problem with a boat is it is not like a car where you can tinker with it in your driveway & then drive it round the block to see if it is fixed! 

Thanks again!


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## Shortdrift (Apr 5, 2004)

Meerkat said:


> I am having problems with my starting battery going flat and am looking for ideas. My first thought was the battery was bad but I have had the battery load tested and it is fine (least that is what Autozone tells me).
> 
> I have an onboard charger connected to the battery. Charge it up overnight and it shows fully charged. Put the boat in the water, run out to where I am going to fish. Shut down the main motor & switch to the Minn Kota (totally separate batteries and circuit) & gas kicker. Starter battery is running the radio, an hds 5, an Elite 7 & the livewell pump. After 5 or 6 hours trolling try to start the main motor & the starter battery is flat. Jump it from the trolling batteries and we are back in business but the dash voltmeter is showing only 10 volts. After a while it crawls back up to about 14 volts.
> 
> ...


I had the same problem two years ago. Cells checked out and the load test was fine. Installed a different battery and no more problem. Considering the age of your battery, I wouldn't hesitate in purchasing a new one.


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## JOHN DETWILER (Apr 25, 2012)

fishdealer04 said:


> Is it possible that the electronics are draining the battery too much for it to crank the main engine? I have a Mercury OptiMax Pro XS and its supposed to have 1000CCA to start the engine. From a lot of forums that I have read people were having trouble with their Opti's not starting after fishing for awhile due to the electronics being hooked up to the same starting battery and it did not have enough CCA to start the main engine. Since you have had your boat for 5 years and never experienced this before it seems weird unless the battery is finally starting to die?


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## JOHN DETWILER (Apr 25, 2012)

I would make sure all the ground connections are cleaned completely with sandpaper and make sure they are all flat for more surface area.


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## RJohnson442 (May 14, 2013)

Check all your connections first. Once things start to heat up the voltage drop will become greater and maybe why it only doe it once it's warmed up. Most high end battery testers will be able to tell you if you have a dead cell. With everything OFF check for draw from the main battery to see if something is stealing voltage. You could also open the batter up and test each cell.


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## G.lock (Apr 1, 2014)

I never had a interference problem, but I have a very basic 12/24 volt trolling system.
The comment on checking grounds also sounds good.
A separate buss for electronics also makes sense.


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## sherman51 (Apr 12, 2011)

G.lock said:


> I never had a interference problem, but I have a very basic 12/24 volt trolling system.
> The comment on checking grounds also sounds good.
> A separate buss for electronics also makes sense.


is it a lead acid battery?? I have had batteries do this when the acid/water got below the tops of the plates in my battery. they would charge up and test good but the acid/ water level was so low they would drain in a hurry. I would check the acid/water level in the battery. chances are you need a new battery. starting batteries wasn't designed to be slowly discharged and charged over long peroids of time.


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## bountyhunter (Apr 28, 2004)

Meerkat said:


> Thanks for the ideas guys!
> 
> Fishdealer & Bountyhunter - I have had the boat for 5 years but the battery was replaced 2 years ago. But even though it tested good I am inclined to suspect the battery. I am thinking I have a new battery in my truck so I may put that in the boat, hook it up, switch on all the electronics and see if it drains the truck battery too.
> 
> ...


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## bountyhunter (Apr 28, 2004)

go to radio shack and buy a strip to run all these wires to , then the only thing on the battery is your motor wires and two wires going to the strip, FUSE EACH piece of equipt you got on that strip. neat easy to work with and safer.


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## Meerkat (Aug 10, 2008)

I charged the battery, then switched on the equipt I normally run while trolling. I checked the amp draw (2amps). Then I left it on and checked the voltage every 15 mins or so. Started at 12.6 volts but within 3 hrs it was 10.5 volts. I have a new battery in my truck so I switched them out & did the same thing. After 3 hrs the truck battery was still 12.4 volts. So looks like the battery tested good but is bad.

Sherman - It is a lead/acid so am going to check the fluid level but I suspect that if it is down, then I have left it too late and will need a new battery.
Bountyhunter - I think I am going to do as you suggest and take the opportunity to put in a fuse block.

Thanks for the help guys - I will let you know how I make out.


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## ohiojmj (Apr 16, 2004)

y guess would be the battery, needing replacement after 5 years anyway. I'm going to Erie tomorrow. Let me know where you are launching if you're going tomorrow. I'll be glad to help if you get in trouble. I'll pm my phone cell number if Ican figure out this new format


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## large6er (Sep 1, 2013)

Meerkat get one of these spade bus bars and make life easier on your self. This will really clean up your wiring and ensure good clean connections.
http://www.overtons.com/modperl/pro...Block-6-Circuits-w/Cover-Negative-Bus&i=71230


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## Meerkat (Aug 10, 2008)

I replaced the battery yesterday. Still have the same problem. I intend to go to the spade bus bar - looks great but first I have to track down what is causing the battery to discharge so quickly. 

I am baffled so i posted a request for recommendations for a good electrical guy. If any of you know someone please let me know. 

Thanks for all the help!


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## tomb (Oct 9, 2004)

Meerkat said:


> I charged the battery, then switched on the equipt I normally run while trolling. I checked the amp draw (2amps). Then I left it on and checked the voltage every 15 mins or so. Started at 12.6 volts but within 3 hrs it was 10.5 volts. I have a new battery in my truck so I switched them out & did the same thing. After 3 hrs the truck battery was still 12.4 volts. So looks like the battery tested good but


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## tomb (Oct 9, 2004)

Entirely possible you keep getting junk batteries off the shelf.


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## Misdirection (Jul 16, 2012)

How is my your on board charger mounted? It can't be touching the aluminum (nor its mounting screws). I'm assuming an aluminum boat here...the easy way to test is charge up the battery and disconnect from the battery and repeat the test...but I think you have a short somewhere that is grounding out and killing the battery.


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## tomb (Oct 9, 2004)

Most responding are missing the sentences stating the truck battery maintained 12.4 volts for three hours with all equipment running.


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## Meerkat (Aug 10, 2008)

Yesterday I went through the boat. Traced and labeled every circuit. Checked and cleaned every terminal. Replaced any terminals that looked suspect. Tested each circuit for continuity/grounding issues. I did not find anything obvious but who knows...

Also brought up the voltage indicator on the Lowrance displays so I can monitor the voltage. I fully charged the new battery & switched on the electronics. I did not want to run the livewell pump continuously when it was dry so instead I connected the navigation lights that draw about the same as the livewell pump.

I am monitoring the battery. If it holds up, next step will be to run the same test on the water, this time with the livewell pump running.

Thanks again guys for all the ideas & I will report back on what I find.


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## steelneyes2 (Jul 19, 2011)

Meerkat said:


> Yesterday I went through the boat. Traced and labeled every circuit. Checked and cleaned every terminal. Replaced any terminals that looked suspect. Tested each circuit for continuity/grounding issues. I did not find anything obvious but who knows...
> 
> Also brought up the voltage indicator on the Lowrance displays so I can monitor the voltage. I fully charged the new battery & switched on the electronics. I did not want to run the livewell pump continuously when it was dry so instead I connected the navigation lights that draw about the same as the livewell pump.
> 
> ...


Everyone seems to be missing another obvious concern. What is the voltage at your battery terminals with the big motor running? It should be around 14 volts or your stator or voltage regulator has gone out. You can't get many starts out of a battery that isn't recharging when the big motor is running, and it can actually discharge a battery fast. The old battery needs to be replaced since the truck battery held up fine, as it should. Then you need to check terminals with motor running. What is year and model of big motor? 
Went through the same thing with mine last year, although I had nothing running on the cranking battery but the main motor. Cranker was only 2 years old but bad regulator/rectifier killed it in 3 trips. Replaced battery, same problem. Checked battery voltage when running, 12.6 replaced regulator/rectifier, recheck, 13.8V at idle, problem solved/


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## steelneyes2 (Jul 19, 2011)

BTW .012 amp draw would be typical of a fuel injected motor, computer draws tiny bit of voltage whenever battery is hooked up, just like a car. It would drain a good battery over the course of a month or two, but is not your problem.


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## Meerkat (Aug 10, 2008)

Okay - so started the day with a fully charged NEW battery. Charged via onboard charger. Supply voltage on Lowrance showing 12.6 v. Fire up the main motor & supply voltage goes to 14 volts. Run out to fishing spot, shut down & troll for 8 hrs. At the end of 8 hrs supply voltage showing 11.9 volts. Go to start main motor, turns over and starts up just fine. Running back in the supply volts is showing 14 volts.

Now I may have cleaned up some issues like suspect/dirty terminals but for me it seems the bottom line is a bad battery that was testing good. Right? Is there something else I am missing here? Is it normal that after 8 hrs of running 2 fishfinder/chartplotters, a vhf radio & the livewell (abt 2 amps total) that the voltage would go from 12.6 fully charged to 11.0?

Thanks again for the input & hopefully your answers to my dumb questions will help someone else...


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## RJohnson442 (May 14, 2013)

Id suggest running all your electronics on the deep cycle. And only use the other battery for the motors. Thats too much of a drain on a regular battery. Add in the heat of the summer and it will be even worse. Does the kicker have an alternator on it? You can also get an asr( automatic switch relay) it will automatically charge the weaker battery and cut off one if it dips below a certain voltage.


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## steelneyes2 (Jul 19, 2011)

Meerkat said:


> Okay - so started the day with a fully charged NEW battery. Charged via onboard charger. Supply voltage on Lowrance showing 12.6 v. Fire up the main motor & supply voltage goes to 14 volts. Run out to fishing spot, shut down & troll for 8 hrs. At the end of 8 hrs supply voltage showing 11.9 volts. Go to start main motor, turns over and starts up just fine. Running back in the supply volts is showing 14 volts.
> 
> Now I may have cleaned up some issues like suspect/dirty terminals but for me it seems the bottom line is a bad battery that was testing good. Right? Is there something else I am missing here? Is it normal that after 8 hrs of running 2 fishfinder/chartplotters, a vhf radio & the livewell (abt 2 amps total) that the voltage would go from 12.6 fully charged to 11.0?
> 
> Thanks again for the input & hopefully your answers to my dumb questions will help someone else...


Yes that's about normal, especially if you are transmitting on the marine radio. Glad you got it all sorted out. As others have mentioned, it is best just to have a dedicated cranking battery. If you were to run your trolling motor batteries down to the point they wouldn't jump the cranker, and the cranker is run down too, you could be stuck in a bad way. At least consider a combo, starter/ deep cycle that will tolerate slow discharge better than a starting only battery. The difference is in the design, starting battery is able to deliver intense amps and fast discharge without overheating to start a motor. Deep cycle meant to discharge 35 -40 % and recharge many times without damaging plates inside.


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## tomb (Oct 9, 2004)

Sounds normal, if kicker isn't electric start. Are you using a dual purpose or standard cranking battery?


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## Meerkat (Aug 10, 2008)

Starting battery is dual purpose. 

I thought of putting the livewell on the trolling batteries but it is a 24 volt system. 

Like the idea of alternator on kicker. Doubt if my old 2 stroke johnson can handle it but maybe i can persuade my honey i need a new kicker ;-)


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## RJohnson442 (May 14, 2013)

You can still hook the livewell up on the trolling battery just connect to one for 12 volts


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## Meerkat (Aug 10, 2008)

RJohnson442 said:


> You can still hook the livewell up on the trolling battery just connect to one for 12 volts


Correct me if I am wrong but I think that once I have the trolling motor running, the system is 24 volt. I need to plug in the motor & check the voltage on off just one battery.


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## RJohnson442 (May 14, 2013)

the 24 volts will feed through both batteries (wires to trolling motor). If you connect the hot and ground to one battery you will isolate 12 volts from it (wires to livewell). YOU MUST USE the battery that has the NEGATIVE side of it going to the trolling motor though to protect the 12v circuits you run on it. You can use the other battery but you run the risk of if you ever get a short your 12v becomes a 24v system.


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## Meerkat (Aug 10, 2008)

RJohnson442 said:


> the 24 volts will feed through both batteries (wires to trolling motor). If you connect the hot and ground to one battery you will isolate 12 volts from it (wires to livewell). YOU MUST USE the battery that has the NEGATIVE side of it going to the trolling motor though to protect the 12v circuits you run on it. You can use the other battery but you run the risk of if you ever get a short your 12v becomes a 24v system.


Thanks! I think I will do that. It is not difficult & it is a short run from the livewell switch to the trolling batteries.


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## viper1 (Apr 13, 2004)

Two batteries in all mine. Starter on Battery 1 and every thing else on battery 2. Except I have 2 bilge pumps, 1 on each battery. If its going to die I want it at the dock. Other wise I much prefer my starter battery stays full and drain the 2nd battery.


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