Hunter 35.5 battery discharge

Benny17441 · May 7, 2015

There are 3 ways batteries get discharged; 1) There is a load from an electric appliance or fixture in the circuit. 2) they have a low rate of self discharge(months) 3) weak or damaged battery. The way boats are set up usually is that the only fixture hard wired into the batteries is the bilge pump. If the boat is taking in an undue amount of water into the bilge or there is a failure in the bilge switch making the pump run constantly that could be the culprit. You can disconnect the positive (+) battery bank terminal and use a test light to bridge the connection and if the light comes on and the bilge pump isn't running then you have a load in the system. To trace it make sure all the breakers had been shut off and turn them on one by one until the light indicates the circuit where the load is found. If no light comes on then no loads have been found and I would suspect weak batteries. If you can charge and remove the batteries from the boat and take them to an auto parts retailer to have them bench tested. Once you ascertain that your circuits are load free and your batteries are good then you can leave shorepower ON and the charger should maintain the batteries fully charged. If you do that without checking the batteries the charger could be masking or hiding a weakness in the batteries that may only become evident when you are out in the water. Most of us leave the shorepower on 24/7 when docked to keep our batteries charged and some run refrigeration. Another thing you need to check is that the charger is working. The charging leads should connect to the individual banks. while charging take a multi-meter and check the voltage at the batteries; it should be in the 13V range. Make sure all connections in the battery cables, terminals and charging leads are clean and tight. There is a lot more to learn about batteries and 12V systems so you may need to do some reading. a good starter would be "Sailboat Electrics Simplified" by Don Casey.

Stu Jackson · May 7, 2015

Charlie Wing's sailboat electrical book is also very good.

You could read some of these, too.

Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html

Bill Roosa · May 7, 2015

I would second averything Benny said except you need to be aware of other "always on" devices. Mostly the stereo and VHF that have "memories" that need a always hot wire. These would never drain your battery in less that 3 months but they do give an indication of battery drain using Benny's test. A multimeter on the 10 amp setting will tell. Hook it up the same way Benny described the test lamp. A stereo memory might draw 0.05 amps max even with the CB turned off. Anything over that would be an indication of a problem.
The most common problem with batteries is the terminals becoming corroded. This prevents them from both discharging and being charged.

ice breaker · May 7, 2015

sls11115 said:
I am a new Hunter owner and am having problems with constant battery discharge. I can find nothing in the owners manual about how to set up the electrical system if the boat is not going to be used for over a week. Should I leave the AC Shore Power connected and on--will that charge the battery while the boat is not in use? Any suggestions would be appreciated.
Thanks,

Ryan

Ryan: WELCOME!

Yes leave the shore power plugged in and turned on. Make sure that the battery charger is in the on position on the electric panel.

On my boat I leave the 12 volt fridge on, the freezer on. That is it. I need cold beer and frozen pizzas.

On the 120 volt side it is the charger that is on. Everything else is off. If you have AC, you might want to leave one of the two units on, once it warms up, in the AWAY mode so that it dehumidifies your boat.

This should keep everything fine.

Have fun!

Hunter 35.5 battery discharge

sls11115

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Benny17441

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Stu Jackson

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Bill Roosa

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ice breaker

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