Electrical Draw on Port Battery

B

BUBBA

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Joined
Jan 1, 2000
RO Number
2190
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152
Hi Guys I have a 1984 Tiara Continental and
there is a constant draw of .5 amps in the port battery. We hooked up a meter and began pulling fuses both in the cabin and on the dash and nothing made a difference. We pulled the power
wire off the alternator as I was told that a bad diode could cause this problem but nothing change. The only way to stop it is to turn off the battery switch. Anyone have an idea what would be drawing .5 amps and not be fused??
It's driving me nuts.
 
CO detector

Music radio ( clock circuit )

I am sure there are other candidates.
 
a) I don't know; check the specs for the device.

b) the half amp could be caused by more than one device.

c) forgot to mention: some bilge pumps do not use a float switch, but are either electronic ( small potential drain ) or a pump tht periodically turns on to test for water ( that timer also has a small drain )

fwiw: half an amp at 12v equates to 6 watts. This may help in finding the source. Whatever the source, it bypasses the circuit breaker panel but is connected between the panel and the battery switch. Only a very few devices should do that ( assuming they are wired correctly ).
 
I had a similar thing happen on my boat. When prepping for fall haul out I was cleaning out the shower sump and when I put my fingers into the water to activate the float switch and felt the DC electric! All season long the battery that pump is connected to kept running down. Replaced the sump drain and pump and haven't had the problem since.
 
Are you reading a panel ammeter?
If you have multiple + leads off that battery and switch , remove only 1 at a time and see when the draw disappears.
There may be inline fuses within ~~7" of the battery or battery switch.
 
Assuming you have a radio of some sort do you need to reset the stations etc each time you turn off the main battery switches - if not then there is a direct connection to the positive side of the battery (the same as in a car) Although this draw seems a little high for that but it may be part of your issue

Brad
 
We eliminated the bilge pump. We were using a multi meter direct from the battery. We did go through all the fused connections. I don't even use the music radio but I don't know how it was wired
as the previous owner installed it and cannot ask him because he is deceased.
 
you are going to have to run down the power cables to find your leak. have you looked at the stereo as a source?
 
If you don't even use the stereo , you might as well disconnect it at the radio so the settings memory could not draw.

Or at least test for constant minor draw right at it's power connectors, with stereo off.
 
You are doing it backwards. The short can be before the fuse and/or insufficient to break the fuse. There has to be a distribution bus off the battery cable. Find that, physically disconnect everything from the bus. Connect your meter as you described, start reconnecting with everything off and all breakers and fuses pulled. When you see the draw, you got your culprit. I had a draw on a Cessna 402 like you describe and it turned out to be the reading light.
 
Thanks Gee Bee you have a point. Going the other
way has not shown the problem. I will try to
find the distribution panel. It is NOT the stereo or anything else powered off the fuse panel
 
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