Boat draining battery, but no electronic...

relocyo

Chief Petty Officer
Joined
Apr 14, 2010
Messages
446
Reading another thread reminded me of a problem on my 1978 johnson 85hp , I left the battery hooked up during the work week, and come weekend the battery was dead, so dead it wont keep/hold charge at all... The strange thing is at this point I dont have any electronics hooked up to it, only a tach that I unhooked the little light to. Its a '76 glastron gt 150 that im slowly making whole again... All the wires under the dash were cut by PO , obviously the keyed ignition at the dash is connected but thats it, no tilt/trim unit on the boat either... Any ideas? So far I just unhook the battery when im done, but I really dont wanna fry another $220 battery... Thanks, im sorta dumbfounded... Oh and bilge pump hooks to the battery at its posts, so itsnot that either...
 

Stachi

Lieutenant Commander
Joined
Jul 14, 2009
Messages
1,671
Re: Boat draining battery, but no electronic...

What position was the ignition key in , when you discovered this ? Not implying an insult in any way ,... I always start with the simple solutions first when diagnosing a problem..... I can't tell you how many times , with the doors shut , that the dome light comes on when a booster pack is connected to a dead battery car I am working on....
 

relocyo

Chief Petty Officer
Joined
Apr 14, 2010
Messages
446
Re: Boat draining battery, but no electronic...

Ignition is off and key was out, its a manual choke at the engine (a flapper mechanical switch) and like I said 4 or 5 days battery was so drained it was ruined and wouldnt even hold a tiny charge... :( its a headscratcher....
 

skyking897

Petty Officer 1st Class
Joined
Mar 21, 2010
Messages
208
Re: Boat draining battery, but no electronic...

You could always hook a volt meter or amp meter up in series between the battery and one of the battery cables to check and see if there is actually some sort of voltage/amperage draw that is killing the battery. If so, it's just a search and destroy to find out what it is. Then there is always the possibilty that your battery is a dud.
BTW, if your bilge pump is on a float switch, check that, since is is hooked directly to the battery.
 

relocyo

Chief Petty Officer
Joined
Apr 14, 2010
Messages
446
Re: Boat draining battery, but no electronic...

I forget how old the battery was, but it worked great and cranked strong before I zapped it... Im not that great with electricity, besides hooking up car stereos its sort of a mystery, electricity doesnt like me either, it reaches out and grabs me every chance it gets :redface:
But I have access to a volt meter, what would be the recomended procedure for this test? I had someone else say they installed a battery switch and that resolved their problem as it was the same as mine, but I only have the 1 battery...
 

rockyrude

Lieutenant Junior Grade
Joined
Sep 10, 2007
Messages
1,120
Re: Boat draining battery, but no electronic...

If it only took 4-5 days to kill the battery, it sounds like a big draw on the battery. Put an ammeter between one of the battery posts and its cable. The amp draw showing should give you a hint to what it is. If you don't have any other gear in the boat, the two big suspects I would look at would be the bilge pump and the starter solenoid. Some old timers might remember putting the ignition wire on the wrong post would cause the solenoid to energize just enough to cause a constant drain.
 
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