Help, something draining cranking battery???

[Zel]

One year and two completely dead new cranking batteries. Something is draining the cranking battery and I can't figure it out. When I got it winterized last year at the local marine shop, they fixed the wiring problems for $250. Although some of the wiring problems are fixed (switches not working), the drain continues. Nothing is turned on (Fish'n'Ski), I've checked and checked. I charge it the night before, and by morning, it's completely dead (thats less than 8 hours). Right now I use a deep cycle instead of a cranking battery so the battery won't get destroyed when it gets completely drained. Any ideas to point me in a direction? Thanks.

[HPBB]

you said something that should jump right out at you. but I know how it gets when you are triing to find a problem you over look some stuff. you said that some of the switches do not work. Right? well, if they are not working you don't know if they are on or off. I would get the switched fixed. use that as a starting point. if that doesn't fix it I would make sure the battery is fully charged then disconect everything from it at hook things up one at a time. if you hook your motor up first and it doesn't drain it, then its not it. then hook up you ( lets say) lights, battery not dead, then its not them. keep doing this till the battery is drained then you know what is the problem. I know it will take some time , but you will find the problem,

and here is one thing. make sure your key is in the off position, or better yet take the key out. on my one boat  the trim would only work when the key was in the run position, but if you forgot to turn the key "off" it would drain the battery fast.

[burleytog]

Remove equipment until it stops.

[Zel]

Thanks guys.  I'm not very good with electronics.  I take the key out after every trip.  All the switches now seem to work since getting them fixed at the marine.  My 2 depth finders and CD player are the only additional accessories tied into the cranking battery.  I take them out of the boat after every use.  The remainder of electronics don't work unless I turn on the "Power" switch on (at least that's what I've noticed), except for the trim switch on the big motor.  Therefore I think there is nothing else to turn off.  Also, is there a way to test for a drain of power?

[Wayne P.]

Do you have a Lowrance unit with GPS?

[Zel]

Do you have a Lowrance unit with GPS?

No, I've got an Eagle Cuda 242 for the front deck, and an Eagle Cuda 250 with GPS mounted on the dash (but I think Lowrance makes the Eagle brand).  I do disconnect both fishfinders and the CD player after every use and store them in the garage.  I only put them back on the boat right before I launch.

[Wayne P.]

The reason I asked about the GPS is that the newer Lowrance units need separate power for the GPS antenna and disconnecting the unit head leaves the power still connected to the antenna. If your Eagle unit is a comparable setup, that is your problem if it is not connected to your console power cutoff switch but directly to the battery. Also some trolling motors use a small amount of electrical power even when not being operated. Unplug your trolling motor-that should be done anyway when the batteries are being charged-safety precaution.

[Zel]

Thanks Wayne P.  The Eagle Cuda 250 has a built in antenna.  I unplug the trolling motor after I get off the lake, and don't plug it in till right before I launch.  I don't seem to have a drain on the trolling motor battery, only the cranking battery.

[Wayne P.]

Next step, disconnect all the wires from the ( + ) side of the starting battery. Lightly touch the outboard cable to the ( + ) battery connection and see if a spark occurs. Do the same with all the other conductors that were connected to the battery while looking for a small spark. Which ever creates a spark is the problem connection. The contacts in the key switch could be a source of the drain as well as the trim switch/s. My trim switches will operate the trim with the key off and removed.

[Zel]

Thanks Wayne P, I will definately give that a try when the motor finally goes down on its own.  When the motor is raised, and the cranking battery is dead so the trim switch doesn't work, you can't open the cover to the battery area to get to any of the cables or batteries (a whole other headache).

[Wayne P.]

You don't have to wait for the trim to leak down, just turn the control valve screw and it will let the motor down ( do it slowly though )

[Way2slow]

Lets make it simple so you can check it.

Get you about a 15 watt 12 volt bulb with a bulb socket that has two wire or one you can attacht wires so the bulb will lite up. Check it across the battery to make sure it does lite up.

Now disconnect all the wires from the positive post of the battery, and connect one of the bulbs wires to the positive post. The one bulb wire is all you want on the postive post. Now touch each wire you took off the positive post to the other wire on the bulb. If the bulb does not glow, that wire is ok and do another one. Do this with each wire that was on the battery. If one makes the bulb glow, that wire is causing a drain on the battery. If it happens to be the motor cable, you will need to move the bulb out to the stater solenoid on the motor, this is where the engine's power is usually connected. There will be the large battery cable and one or two smaller terminals on the battery side of the solenoid. Take the smaller one off and leave the battery cable and connect your bulb. Touch the smaller terminals to the other bulb wire is see if the bulb glows. If so, keep chasing wires until you find what's make the bulb glow.

Just be sure all switches are off before you start or you're going to feel like an idiot when you spend two hours chasing wires back to a switch that's on.

If none of them cause the bulb to glow, get you a new battery.

[Wayne P.]

Way2slow, that is a good suggestion, but not as much fun as trying to get sparks, LOL