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  New battery and on-board charger not working.

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Author Topic:   New battery and on-board charger not working.
WT posted 08-08-2007 12:33 AM ET (US)   Profile for WT   Send Email to WT  
I had a new battery and on-board charger installed last week. My son took the 170 Montauk out today for the first time with the new components. The battery was fully charged (green light on the charger) prior to using the boat today.

After he got home, my son plugged in the cord to recharge my batteries. The new battery after 6 hours is not recharging. Usually the starting battery recharges in a matter of a few minutes.

I have a 2007 Mercury 90 hp EFI 4 stroke "Veradito" that was installed last February to replace my old Mercury 90 hp carbureted 4 stroke.

Other than a defective battery or charger, could my outboard in someway be draining my starting battery?



jimh posted 08-08-2007 07:58 AM ET (US)     Profile for jimh  Send Email to jimh     
Warren--The outboard should not have any parasitic current when it is off, other than perhaps a very small leakage current in the diodes of the alternator. That ought to be less than a milliampere or two.

You can measure the current drain on the battery in this condition by temporarily disconnecting the positive battery lead and inserting an ammeter (which is usually available as a function on a digital multimeter). Set the current scale to a low level and see if there is any appreciable parasitic current flow from the battery (with the battery charger turned off and disconnected).

Connect the positive lead of the meter to the positive terminal and the negative lead of the meter to the conductor that normally connects to the battery. A positive flow of current indicates a current flow away from the battery, and a negative current flow indicates flow of current into the battery (as from the charger).

Chuck Tribolet posted 08-08-2007 08:42 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
What sort of charger? (Brand and model would be helpful).

If it's a smart trickle charger, and somebody left the
something turned on (say the electronics or the bilge pump)
from the ramp to home, it may take several hours or even days
to charge. I've done that a couple of times.


WT posted 08-08-2007 10:51 AM ET (US)     Profile for WT  Send Email to WT     
Thanks for the input. I'm calling my electronics guy this morning.

Chuck here's the charger that is installed.


WT posted 08-08-2007 12:41 PM ET (US)     Profile for WT  Send Email to WT     

My new charger is only at 4 amps (my other charger is 15 amps).
I'm told that the new charger will take a lot longer to charge my starting battery.

Before charging my batteries I turn off my Perko switch which shuts off all the electronics on my boat.



Plotman posted 08-09-2007 11:43 PM ET (US)     Profile for Plotman  Send Email to Plotman     
I guess I'm confused as to why the batteries would need to be charged after a day on the water. Are you talking about something like a trolling motor battery bank?

Maybe the charger isn't charging because the battery is already fully charged - as I would expect it would be after a day of running.

I have an onboard charger that was on my boat when I bought it, though frankly I have never used it. My batteries get pulled out of the boat and put on a trickle charger on a timer (4 hours a week) over the winter. Other than that, they get charged by the alternator during use. This past winter the boat was stored in heated storage, and I did nothing with the batteries, and both engines started right up after 7 months of no use.

Do most folks "charge up" after a day on the water?

WT posted 08-10-2007 01:37 AM ET (US)     Profile for WT  Send Email to WT     
I have 2 trolling motor batteries that need recharging after a day of black bass fishing.

Here's a picture of my son with a 6.5 and 5 pound bass. Ne uses my Montauk more than me. current=DSC02373.jpg


jechura posted 08-10-2007 06:20 AM ET (US)     Profile for jechura  Send Email to jechura     

I'm a little confused also. It sounds like you have three batteries on the boat and a one bank charger when you should have had a three bank charger.


Chuck Tribolet posted 08-10-2007 06:56 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
The starting battery should be fully charged by the Merc's

Two trolling motor batteries, mmmm. 24V trolling motor? Or
do you switch a 12V motor betweeen two batteries?

How do you switch the charger between the batteries?

I'd start by putting a digital voltmeter across the battery
both under charge and after sitting for 15 minutes not


Plotman posted 08-10-2007 03:59 PM ET (US)     Profile for Plotman  Send Email to Plotman     
You need a 3 bank charger - this a charger with three separate charging circuits - one for each battery.

Here is an example: jsp?id=0043939018868a&type=product&cmCat=search& returnPage=search-results1.jsp&QueryText=battery+charger&N=4887& Ntk=Products&Ntx=mode+matchall&Nty=1&Ntt=battery+charger&noImage=0

WT posted 08-10-2007 05:19 PM ET (US)     Profile for WT  Send Email to WT     
I have a 3 bank on-board charger with 3 separate charging circuits that charges 3 separate batteries. One of the three banks, the one that was connected to my starting battery, broke.

Instead of replacing my old 3 bank charger for $350 (2 banks still work). My electronics guy installed an additional single bank($100) charger and connected it to my starting battery.

Now I have a single bank charger just for my starting battery. I also still have my 3 bank charger of which I'm only using 2 banks which are connected to each of my 2 trolling batteries.

Each of my 3 batteries has its own separate circuit on-board charger.

My trolling motor is a 24 volt, 72 pound thrust, Minnkota.

Thanks for the input guys,


Nauti Tauk posted 08-12-2007 05:34 PM ET (US)     Profile for Nauti Tauk  Send Email to Nauti Tauk     
My bet is your starting battery is fully charged and doesn't need further charge from the charger unit. If you use the Minn Kota your two bank charger will bring the trolling motor batteries up for you because they aren't recharged as you use the boat....the starting battery does. With regular use the start battery shouldn't need any charging at all.

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