Hooking battery back up for just engine to turn over

brooksville_rebel

Petty Officer 1st Class
Joined
Aug 12, 2011
Messages
240
Hello,
A boating newbie so may seem silly or simple here but I just want to make sure I don't fubar things up.
We just bought a used pontoon. They lady had just put a new battery in on 4/29/13. We have had the boat two weeks maybe. Anyways the motor always turned over, battery seemed fine. Now last two times went out it was dead. So jumped it.
Now we are newbies and our 4yr old was on the boat along with our 5yr granddaughter. They like to flip buttons so figured they had turned something on or maybe I left something on. Charged battery, engine started. Things looked good. Next day dead again. I couldn't find anything left on, but still learning the boat so thought maybe something. Now the only thing I did was remove the old Maxxima radio/cassette deck to replace it with a new one. I have not hooked a new one up yet.
I did some research here and on the internet and did a parasitic test were I pulled the negative cable put the volt meter in series (probe to cable other probe to post.) and with Vmeter on at 10A there was no pull showing up. When flipped to mA every so often I see a flick to maybe 01 but wasn't steady so not sure if a pull or me shaking the probe but that seemed way small to drain it. Tho not sure. Would that small drain over nite ?
So I took the battery out and took it to Auto Zone. They allegedly put it on their machine. Said it take an hour or so. I left and later got a call from them saying it wasn't holding a charge. Okay made sense to me. So I called lady, she found battery receipt and I took it back to Walmart were she got it from. They did their test, says its fine, no problem with it. Now frustrated. So go pick it up. When I pick it up I put the Vmeter on it and it reads 12.77v. Okay. Left it in my van for a couple hours to test it latter. Its at 12.66v. Leave it over nite and this morning its still at 12.66v. So seems to hold its charge. Now I want to put it back on the boat but would like to JUST hook up the motor and not the accessories to it to see if it drains that way.
I notice I have 4 cables coming to the battery,2 red, 2 black. Now there is a thicker red/black set and I ASSUME that this is the cables to the motor and the thinner ones probably go to the console or some were were all the accessories meet up. Is that right ? Will doing it this way even be telling me anything ?
Sorry for the long post but want to make sure you smart guys have all the info to help me out.

Oh and the motor is a 2002 40hp ELPTO Mercury.
Thanks
Mark
 
Joined
Feb 17, 2012
Messages
2,906
Re: Hooking battery back up for just engine to turn over

you should be able to leave the smaller red wire off and test just the motor. It sounds like the battery is failing a load test which im unsure walmart would be able to test. If it was mine i would start the motor a few times then check the voltage to see if theres a major diffrence (Take voltage reading after 10 mins off no load). When you did the amp draw test did you turn on a light (bow light) to ensure you have the meter is hooked up correctly. With the light on you should have seen a 1 to 2 amp draw.
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Re: Hooking battery back up for just engine to turn over

It sound like it is not being recharged by the engine.

Take the meter out on the water with you.
The battery should read 14+ when the engine is running.
Anything less than 13.5 will take weeks to forever to recharge the battery.
 

brooksville_rebel

Petty Officer 1st Class
Joined
Aug 12, 2011
Messages
240
Re: Hooking battery back up for just engine to turn over

So yesterday I hook up just the motor and boom starts with a roar. I only did a second or two.
Now only have the motor hooked up. Now its 84 here in Central Florida and sun is on the boat as it sits in the yard. I check the voltage 5 mins ago and now its down to 12.62. It should not be dropping like this should it ?
Also read more on the battery and its a starting battery not a deep cycle one.
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Re: Hooking battery back up for just engine to turn over

12.6 volts is the NOMINAL Voltage with the Battery just sitting, doing Nothing. NORMAL!

The battery should read 14+ when the Engine is Running.
Anything less than 13.5 with the Engine Running, will take weeks to forever to recharge the battery.

It may read 12.2 -12.4 after sitting for a week or more.
Less than 12 after a week would be suspicious.
 
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