Battery draining

Bonker43

Cadet
Joined
Mar 8, 2010
Messages
14
Hello Fellow Boaters,
I have a Trophy 1802 with a 115 Mercury 4 stroke and I'm having a problem with my battery draining when not in use. I had the boat for 2.5 years before this problem started. The only items drawing power when it sits in my driveway is the carbon monoxide detector, the bow bilge pump in the cuddy and the stern bilge pump. I remove all other devices. I take the drain plug out so water never accumulates to set off the automatic bilges. If i turn off the battery there's no problem, but if I forget to turn it off, the battery is drained enough that after four or five days it won't turn the motor over. Any suggestions? Thanks
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Re: Battery draining

Measure the amount of the drain with an amp meter.
Start pulling fuses until you find the source of the drain.
It could be a bad rectifier in the alternator.
 

KD4UPL

Senior Chief Petty Officer
Joined
Feb 13, 2010
Messages
653
Re: Battery draining

I would have guess the CO detector would kill the battery in 4 or 5 days. I guess not since you apparently have been doing this for 2.5 years. Like UncleWilli said: measure amps and pull fuses until you find the drain.
Does your boat have a stereo? Did you install one recently? Even off these draw power for the clock and memory.
 

colbyt

Master Chief Petty Officer
Joined
Aug 9, 2012
Messages
824
Re: Battery draining

Pure speculation on my part. Any continued use of power when not running will drain an older battery faster than a newer battery as often batteries get weaker before they finally die.

I surely agree with testing things but keep the battery age in mind.
 

UncleWillie

Captain
Joined
Oct 18, 2011
Messages
3,995
Re: Battery draining

I would have guessed the CO detector would take over a year to kill it! Same for the stereo.
If it won't last for a few months something is wrong.
Until we get a measurement of the actual drain, we are just making wild guesses.
I would not expect to anything more than 100mA (0.100Amps) <25mA is better.
 
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