motor battery

Our battery that we use to crank the motor seems to die every three times out on the water, it is just not holding a charge, when we get home and put the charger on it it works great the next time out. we believe it is the alternator on the motor that is going bad and continually draining the battery. I know the battery is good because it is new this year and we had it inspected by interstate also.

in calling a marine shop about this issue, they mentioned that it could be the alternator but that they really believe the issue is that the battery is a cranking battery. he mentioned that since I am running my depth finders, livewell, light and bilge that running a cranking battery is not the right battery to be using. he said that based on what I am using a deep cycle would be more appropriate.

From my understanding a cranking battery for my motor and electronics is the correct battery.

I run a 24 volt trolling motor up front also.

Please let me know what you think.

thanks
Dan

95% chance its the battery. Use your graph as a volt meter. Assuming you have one it should have a display mode that shows voltage. View the voltage with motor off and motor on and running. If the alternator is working your voltage will jump 1-2 volts depending on RPM. If it doesnt you know the engine is not outputing to the battery. Just an eash quick way to check. I know there are other varialbles but this methond has proven worthwhile to me in the past.

How many volts is your alternator putting out when the motor is running? I use a marine cranking battery and run my graphs and gps and livewell, etc. off it and have had no issues.

My starting battery also runs “accessories” like the bilge pump, the interior and running lights, the depth finder, etc. I bought a new battery 3 or 4 years ago and it’s always ready to go….assuming I remember to shut everything off Most of this stuff really isn’t putting that much of a drain on the battery. Depth Finders don’t draw that much, for example. I’d ask another shop what they think.

Rootski

Another troubleshooting tool would be to disconnect your battery after you charge it then connect when you go fishing. If the problem no longer happens then something in your boat is draining the battery. Aren’t batteries a blast! I’ve learned way too much from constantly troubleshooting my own bat problems over the years. I had a wave of them this past year!!

Quote:

---

I’ve learned way too much from constantly troubleshooting my own bat problems over the years.

---

So what do the bats do? Chew through your wires???

Put a volt meter on the battery with the motor running. If the alternator is working, you should get somewhere around 13.8 to 14.2 volts on the meter. If you get that, I am guessing the battery is problem

Had the same trouble with 60 hp merc. 4-stroke voltage regulator was out had it replaced and works good as new. I had that problem for about a year, less than 300$ fixed and dont have to worry about it anymore.

Stop by batteries plus they can test batteries, free.

It pays to load test the battery and check too see if the battery does not have a short in it. Check and see what model of battery you are using. Most dealers install the 24m series from Interstate, which is a deep cell and used as a cranking battery. This battery is plenty good enough to handle most boats. I would suspect like what some of the others have posted, either it is a charging issue or the wires are grounding to the boat some how and draining the battery. It should not be too hard to figure out. Start with the motor first.

We tested the motor yesterday with a multi-meter. When the motor was running, the volts on the batterry didn’t jump at all once the motor was fired up. Based on the input from IDO and our belief, we will be looking too replace the alternator in the coming weeks.

We are running a marine grade cranking battery.

thanks for the help and the detailed responses,

Dan