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Author Topic:   Interstate Battery Dying at 6 Months
Traveller posted 06-01-2008 08:28 PM ET (US)   Profile for Traveller   Send Email to Traveller  
Hi all. My new 2008 Montauk came with two Interstate 24M XHD batteries. I have had the boat for 6 months. My usual procedure is to run the boat on battery 1 for several hours, turn off the motor, switch batteries, and run the boat on battery 2 for the rest of the day. The electronics on my boat include a GPSr-chart plotter- fish finder combo unit, and a VHF radio. The last time I took the boat to the lake, when I switched from battery 1 to battery 2, there was barely enough power to start the Mercury 90 EFI FOURSTROKE engine. I ran the boat for the rest of the day using that battery, hoping the alternator would recharge it.

I have a battery charger that indicates the percentage of charge in the battery. It indicated that the 2nd battery was down to 65% when I checked it. I ran the charger until the battery was fully charged, waited about 30 minutes and checked it again. It had already gone down to 85%, and then this evening it was down to 70%.

Should I take that battery to a local Interstate Battery dealer since a bad battery would be a warranty issue for them, or take the boat back to the dealer (60 miles away) to see if something about the boat is killing the battery?

zotcha posted 06-01-2008 09:06 PM ET (US)     Profile for zotcha  Send Email to zotcha     
I would not normally give my opinion on this but I am as brand loyal to Interstate batteries as I am Amoco fuel. I know, I know! I'd bring that back as soon as I could, BUT, when you remove the battery (batteries), they WILL be stamped with the date inspected. Don't embarrass yourself. Two to three seasons is maximum, even for the backup, electronics, live well, lights, and whatever you want to call it. I got four seasons ONCE, but was well aware of the consequences. Almost religiously buy one a year, and "rotate stock". Good Luck. zot.

BTW, 2002 Harley, factory battery died in 2007. Insisted on Interstate equivalent and have been having problems ever since. No minor discharge as in other models. Just Lack of Use!

Don't buy more ethanol than you need for THIS trip! Michael.

Bella con23 posted 06-01-2008 09:25 PM ET (US)     Profile for Bella con23  Send Email to Bella con23     
Batteries have been known to go out of the plants as defects. However, I believe they are far and few these days.

I would switch off everything on the boat and lift one of the terminals on the troubled battery. Then take a voltmeter or a pigtail light and place it between the terminal and the battery post. There should be zero volts or no light on the test bulb.

If there is a draw, check things like the bilge pump (if so equipped)for a hung up float. Maybe a miswired battery switch.
Remember that a battery that has been allowed to discharge to less than 50, or 25% depending on the type of battery (standard marine or deep-cycle) will lose its ability to hold a charge again.

I am dealing with the same scenario on an Interstate battery that was overcharged due to the charger going bad and charging the battery at 53-Vdc. It will charge to 100% and lose the charge to about 50% overnight. I have it in the shop for replacement.

Casco Bay Outrage posted 06-01-2008 09:56 PM ET (US)     Profile for Casco Bay Outrage  Send Email to Casco Bay Outrage     
While I agree with Joe on troubleshooting. Something else sounds strange.

You said the boat came with two batteries but list only basic electronics. I do not see a second battery option on so I presume the dealer did the install.

You do not mention a trolling motor so why is there a second battery? I have not read it is required or necessary.

If the dealer did the install, take the boat back to the dealer. You paid a lot for that boat and they may have done something wrong. Get them to figure it out under warranty. If the dealer declines to cover it and wants to charge you beg off, call Whaler and have them log your complaint.

Just one opinion.

jimh posted 06-01-2008 10:49 PM ET (US)     Profile for jimh  Send Email to jimh     
The only way to determine the state of charge is to make an accurate measurement of the terminal voltage of the battery after allowing a resting period following any charging without any load draining off the charge. A battery fresh off charging will have a terminal voltage of more than 13.0-volts. After about an hour the charge will return to the normal state. A fully charged battery will measure about 12.9-volts. A completely discharged battery will be around 10.5-volts. The temperature also affects the voltage and charge relationship. See

I would not condemn the battery as having failed based on the readings on the battery charger, unless you have a much more sophisticated battery charger than most.

It is not a good idea to charge the battery for long periods unless the charging voltage is controlled and held under 14-volts. Prolonged charging at higher voltages leads to formation of gas in the cells and loss of electrolyte. Check the water level in the six individual cells. If they are low, fill them with distilled water.

Most battery retailers now have an instrument which will take a measurement of a battery's capacity in Ampere-Hours using a low-current discharge test which will not put a large load on the battery or discharge it much at all. If you have doubts about a battery, have it tested on one of these battery instruments. The results should give you a measure of the battery capacity.

Also, the advice to check for a parasitic load in your vessel is a good suggestion. It does not take much current to drag a battery down.

davej14 posted 06-02-2008 08:06 AM ET (US)     Profile for davej14  Send Email to davej14     
Is anything connected directly to your battery? If you store the boat with the battery switch in the "off" position, the only load that should bypass the switch is the bilge pump. It is possible that the float switch of the bilge pump is stuck but you should be able to hear it running if that is the case.
Jefecinco posted 06-02-2008 08:39 AM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     
When cleaning the boat after a day of fishing I inadvertently turned the bilge pump on. My pump is very quiet and I didn't hear it running and I was tired so that may have contributed. The next morning while installing the cover I heard the pump running and turned it off.

I have dual Optima batteries installed and they were virtually unaffected by the pump running for about 14 hours. I did charge the batteries before the next outing.


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