Batteries Completly Dead?

[dmac14]

So I tow my boat to the launch today, luckily the a very close bay, and go to trim the motor down and nothing. Confusing yes so I change out that battery to one of the spare deep cycle batteries I have and it works so I launch the boat and come back to try starting and nothing..Fish finder won't even turn on motor does not trim back up. This is the second battery and I throughly checked the connections on both batteries and still nada. Now recently I began using the actual onboard charger, before I was simply plugging each battery into a portable charger. Could this have anything to do with it? Could the charger actually drain down the batteries? I had the charger plugged in all last night and unplugged it prior to leaving this morning. Both of the batteries are less than a year old.

I am very confused at this issue, fishfinders don't draw that many amps so Idk why it wouldnt turn on, the batteries cannot be that dead, or could they be?

arrggh darn boats. Ruined a perfectly good day off.

[Long Mike]

Your on-board charger will not drain your batteries. It would be nice to know what the voltage is on the batteries now that you have the boat back in the drive. I suspect you have a short to ground in the cranking battery circuitry. Way2Slow should be able to shed some light on this.

[Jig Man]

Go to an auto parts place and buy you a cheap hydrometer. Check to see what it shows. Then charge them and see if they take a charge.

[Way2slow]

Wy me?

Personnaly, I think you waited to long to get an onboard charger. I would have to guess you ruined the batteries before that, but before jumping to that conclussion, you will need to check the batteries. Start by charging them to a full charge, or as full as they will get, hopefully they will charge up enough for the charger will cut off. Either use your on board or a sererate charger. Using a DVM, after it has charger some, take a reading across the battery and make sure the charger is charging, minimum of 13.8 VDC but should be closer to 14.6 VDC.

Once the battery is fully charged let it sit at least a few hours, better overnight, then using a DVM, check and see if it has 12.6 - 12.8 volts. Install the battery as the cranking battery, if not already with the DVM connected across it. Pull the Emergency Kill Cord so the motor won't start. Now, using the key switch, crank the motor over for about 15 seconds while watching the DVM, and see how much voltage drop it has. It should not go below 10.7 VDC, if it does, the battetry is no good. It's only marginal if it drops to 10.7.

You don't need it on the hose to do these checks because the motor should not be able to start with the kill cord pulled.

If they are still under warrenty, then take them back if they fail this load test.

Oh, the reason I said you probably ruined them before connecting the onboard. The batteries should be charged every six weeks or so while not in use. They also should be charged within 12 hours after use, and not just wait to the day before you get ready to go to the lake.

[Sfritr]

Wy me?

Personnaly, I think you waited to long to get an onboard charger. I would have to guess you ruined the batteries before that, but before jumping to that conclussion, you will need to check the batteries. Start by charging them to a full charge, or as full as they will get, hopefully they will charge up enough for the charger will cut off. Either use your on board or a sererate charger. Using a DVM, after it has charger some, take a reading across the battery and make sure the charger is charging, minimum of 13.8 VDC but should be closer to 14.6 VDC.

Once the battery is fully charged let it sit at least a few hours, better overnight, then using a DVM, check and see if it has 12.6 - 12.8 volts. Install the battery as the cranking battery, if not already with the DVM connected across it. Pull the Emergency Kill Cord so the motor won't start. Now, using the key switch, crank the motor over for about 15 seconds while watching the DVM, and see how much voltage drop it has. It should not go below 10.7 VDC, if it does, the battetry is no good. It's only marginal if it drops to 10.7.

You don't need it on the hose to do these checks because the motor should not be able to start with the kill cord pulled.

If they are still under warrenty, then take them back if they fail this load test.

Oh, the reason I said you probably ruined them before connecting the onboard. The batteries should be charged every six weeks or so while not in use. They also should be charged within 12 hours after use, and not just wait to the day before you get ready to go to the lake.

Because you ROCK......

[dmac14]

Alright, hooked up the voltmeter, at each of the three charger outputs, one was at 14.2v and the other two were at like 13.5v. Put it on the charger today and I will let them sit tonight and test it tomorrow morning.

Quick question though, when charging are you supposed to crack open those top plates? The acid inside seems to be boiling over and around the caps is wet.

[Way2slow]

No DO NOT open the the caps, that only causes excess water loss and gets corrosive acid inside your battery compartment.

A battery is suppose to be making gas bubbles when charging, that's required to properly charge the battery. Excessive gas, rapid boil means that cell is overcharging for some reason, too high of a charge rate or a bad cell. 8 - 15 amps is a normal charge rate and will not cause the cells to gas excessively unless the cell is bad.

What causes a bad cell to boil over is they no longer have the capacity they were suppose to. For instance, a 105 Ah battery, each cell is a 105 Ah, but because of sulphation or other reason, it may only be a 10 Ah cell. A 105 Ah cell charges at 8 - 15 amps with no problem, but a 10 Ah cell can only handle about two amps max, so when your charger is hitting it at it's normal rate, it's boiling the crap out of it.

[TimJ]

way2slow...I have almost 14.6VDC at the battery while charging and 12.9VDC on the battery after sitting about 4 hrs.

I will wait until tomorrow morning to re-measure if better.

My chargers never go lower than maybe 3A, even after charging overnight. (12VDC, 10A charger)

The batteries start out strong but do not last into the day.

If you recall, I was the person corrected here for giving some bad info on treatment of DC batteries. As it turns out, my original advise from yrs ago was wrong. I have taken the advise of those here who know.

I use 2-type 31, both are in their 4th season...and they have been mistreated, ie, I ran them down severely before charging.

I am thinking that I may have 1 or more reduced capacity cells in each battery due to my miscare.

My thought is to go purchase 2 new batteries and start again, knowing what I know now.

Any input will help.

Thanks

Tim J

(edit...chastised was a bit harsh, sorry)

[TimJ]

ok, I let the batteries sit overnight and still have 12.8+VDC on both. after re-reading the post about the boiling, I recalled that when they are charging, there is at least a bit of "boiling" or leakage from both batteries, both caps on each. the fluid levels are what I would consider ok (definitely not close to the caps) and are equal in each cell.

any input is appreciated. thanks.

Tim J

[NBR]

There is a step in the filler hole on each cell the water should be up to that level. Fourth season on mistreated batteries makes me think they have failed. I assume the boat is on a trailer if so you can pull it to an autostore and have the batteries load checked Wal-Mart's tire service can do it.

[TimJ]

ok. gonna do that today or tomorrow morning. would have replaced them but didnt know about the load test. thanks.

Tim J

local Canadian Tire does the tests, never knew. learned again. thanks

Edited July 9, 2011 by TimJ

[dmac14]

Alright I believe I determined one of my trolling motor batteries to be shot, it reads 12v+ but it is definitely not powering the trolling motor like it should, it is a huge difference. So I plan on purchasing a new battery but I want to make sure I am doing it right this time.

What are some basic tips to keeping a battery in good condition?

So far I have heard to charge it directly after use, keep the water levels at the correct level, don't discharge it fully, and when storing keep it charged.

Anything else I am missing? I don't want to kill another $100 battery.

Thanks

[Way2slow]

I hate to burst your bubble but you are already planning on ruining it as soon shortly after installing it. You can't replace just one battery, they both need to be replaced. Put a new battery in a series setup and it will be doing all the work and will probably kill it before the end of the season

[Sfritr]

I hate to burst your bubble but you are already planning on ruining it as soon shortly after installing it. You can't replace just one battery, they both need to be replaced. Put a new battery in a series setup and it will be doing all the work and will probably kill it before the end of the season

X2

Always purchase your series batteries in pairs. They need to be fully charged in tandem otherwise one will ruin the other by overworking.

[dmac14]

X2

Always purchase your series batteries in pairs. They need to be fully charged in tandem otherwise one will ruin the other by overworking.

Its just a lone battery, not in series. Down the road I might buy another and run them parallel but for now it is just one.

Edit: Is it bad to run in parallel if they are not the same?

[Ann-Marie]

Yes running in parallel is OK for unmatched batteries.

To answer your earlier question about battery life, the biggest killer of batteries is over discharging. For maximum battery life they should be discharged no more than 50%. I forget the actual numbers but its something like for every 10% below 50% you cut the life in half. So a 5 year battery at 50% is a 2.5 year at 40%, 1.25 at 30%, 8 months at 20%, 4 months at 10% and 2 months fully discharging.

So if you were to add your extra battery up front you could more than double the life by minimizing depth of discharge and actually save money over replacing one a number of times.

[dmac14]

Awesome thanks ann-marie, looks like I will do that then.

[Way2slow]

Say you run one 105 amphour battery and you run it down in four hours, if you run two 105 amphour batteries in parallel, they will probably last about 10 hours.

While yes, you can run any two 12 volt batteries in parallel, they are a lot more efficient if you run simialar batteries.