Cranking Battery problem

edge · Post by **edge** » Wed Jul 18, 2007 5:10 pm

I am using a Group 31 deep cycle GNB deep cycle 1000 cranking amp to start my boat. I have eliminated almost every opportunity of a short being present but she keeps dying in between outings.

What does everyone recommend for a cranking battery for a 175 EFI?

Thanks,
Jonathan

Mark Lassagne · Post by **Mark Lassagne** » Wed Jul 18, 2007 6:24 pm

An easy way to tell if you have a drain on the battery is to disconnect one terminal and run a 12 volt test light in series. Connect one end of the test light to the battery and the other to the removed cabel if it lights up you have a .75 amp or more drain on the battery. Now comes the fun part to find out where the drain is and that can be a story in it's self. Deep cycle batteries are not made for cranking the big motor they are more of a work horse that can be run down and recharged. If you don't have a drain on the system the battery is most likley worn out or defective. AC Delco has a good marine cranking battery C24MF. The Hook carries or can get them.
Check for a drain and feel free to email me maybe I can help. Frank at Inland marine has great service center also.

Good Luck, Mark

Smile_n_Jax · Post by **Smile_n_Jax** » Wed Jul 18, 2007 6:44 pm

What Mark said. Deep cell batteries are not designed for cranking. What you need to get is a regular automotive cranking battery with the highest CCA capacity that you can afford. Your current problem is probably due to the fact that your deep cycle battery will not take sufficient charge from the big motor while running.

edge · Post by **edge** » Mon Oct 15, 2007 5:13 pm

Guys,

I went with the Trojan SM1100...great cranking battery. Tonnes of juice and reliable.

I got SCS 225's for the trolling motor and they have more than enough for a day in the slop.

Gene Buchholz · Post by **Gene Buchholz** » Tue Oct 16, 2007 5:14 am

Do you have a GPS on your boat? If you don't have a manual on and off switch between the battery and the unit the antenna will draw your battery down. The Antenna is running 24-7 without this switch. Don't get this switch confused with the on and off button on your GPS itself, this is a separate switch.

edge · Post by **edge** » Tue Oct 16, 2007 5:35 am

I always unplug the connector for the antenna...I learned that lesson the hard way!

I did buy a battery switch to turn of power to all batteries when not in use but have not had the time to install it.

kopper_bass · Post by **kopper_bass** » Tue Oct 16, 2007 7:46 am

Gene,
I know you've got lots of experience with batteries, so i'll pose this question to you.

So here's the thing about a deep cycle vs. cranking battery that hasn't always been logical to me.

Why do we use a cranking battery for the big engine and then connect all the dang electronics of the whole boat to it that are running all day long? GPS, Fish finders (2) lights, airators (2), etc.
(i already know why we dont connect them to the TM batteries - interference). But, these items do draw a lot of current over the course of the day; and if you're a finesse guy like me who sits in one area for a while, that's taxing on any battery since the big motor isnt really running much.

Wouldn't it be good to have a high CCA battery that is also is a deep cycle for that purpose of pushing out amps all day long?

I mean we all know what happens if you leave your radio, blower, and lights on in the truck for 2-3 hrs without turning over the engine, so why is a boat any different? And yes, i can go 2-3 hours out in franks tract just cruising on the TM without ever cranking over the big engine.

What's your advise Gene?

Thanks,

Kopper_Bass

tap · Post by **tap** » Tue Oct 16, 2007 3:25 pm

I KINDA HAVE THE SAME PROBLEM WITH START BATTERY GOING DOWN IN A COUPLE OF DAYS OF NO USE.BUT,I HAVE AN OPTIMAX 200.DOES THE E C M ALWAYS DRAW POWER?? THANKS

twister · Post by **twister** » Tue Oct 16, 2007 7:59 pm

You know there are dual purpose deep cycle batteries that are designed to drain more than an regular automotive battery. Some of these batteries have high CA and a ton of amp hours for your accessories (livewell, radio, fishfinders, underwater TV, microwave, large screen TV, refrigerator ect.) Maybe your battery is just too old. What tests did you perform? Lights and indicator on chargers are not accurate indicators of a bad battery.

Another way to determine a unwanted power draw is to disconnect all terminals to the battery. Measure the volts. Reconnect all terminals and and measure again. The two readings should be fairly close. If not, disconnect one terminal at a time and measure the voltage until the standalone battery voltage is achieved. Hence, the last terminal removed is the circuit drawing power. If you can't find it you can always install a main power switch!

battman · Post by **battman** » Wed Oct 17, 2007 7:57 pm

The "AGM" Battery is the way to go for this application since all of the additional loads are being put primarily on the Starting Battery.
Northstar-Centennial/Dual Pro Group 24 Agm Battery is rated at 930 CCA, and 1180 MCA With 175 Minutes of Reserve Capacity. This is a Deep Cycle Battery with enough MCA's to cover the Warranty of any Outboard Motor Manuf. This is the best Battery to solve all of these issues. You will Pay twice as much for this Battery, But you get what you pay for. I carry these Batteries, if you want call and i will hook you up!

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