Battery discharge!

[Michael]

I have a 1982 Hunter 27 with a single 12v battery that covers house power and engine cranking. I use very little house power as I day sail only. It powers VHF, bilge pump and low use of pumped water only. I have no problem when out for the day, I always have enough power. My problem starts when I tie the boat up. I have an electronic charger that is powered by a 110v shore connection and which controls the level of charge. While the boat is tied up the only power used is by the bilge pump which will cycle for about 5 seconds every 10 minutes (stuffing box drip, needs repacking).If for some reason I forget to switch on the shore power or if the connection dislodges and the battery charger is not powered the battery will discharge in 2 days to the extent that the engine cannot be started. The battery is new.My question for the forum:Is the bilge pump likely to be draining the battery in that short a period or is there another problem causing the discharge?Thanks.

 

[Phil Pendleton]

Could be

Put an Amp meter in series with the pump and see how much your drawing and time the cycle. Could well be that the pump is draining the battery in 2 days. Sounds more like a trickle than a drip.

 

[Ressler s/v Blowdacious]

New Battery

Just because the battery is new doesn't mean it's O.K. I bought a new battery for my ski boat last summer, towed 150 miles to use the boat and low and behold the battery wasn't strong enough to power a flashlight. it cranked the engine just fine when installed but discharged within the first 2-3 hrs. Bought another battery on-site which is still working just fine after a year. Took the first back, had it load tested and guess what? It wasn't any good. The dealer refunded my money plus the extra that had to pay for the second battery at the resort where I bought it. Good business on the part of the dealer. The first battery was their top of the line. The second was the cheapest that the marina store had. It all boils down to the fact that every manufacturer puts out some bad stuff occasionally. Take your battery in and have it tested.

 

[Clyde Lichtenwalner]

Pump is innocent

I'll guess that the pump draws 4 amps. It runs 30 seconds every hour, or 12 minutes, say 1/5 hour, per day. Thats 4/5 amp-hour per day. This is an inconsequential load for a new battery rated at 80 to 90 amp-hours. The real problem is the charging system on the Yanmar. You are probably not motoring enough at the end of the day to make up for the load imposed by your other accessories while sailing. The battery is not even close to fully charged when you reach the dock.Of course, it could be any of the other things mentioned as well.I would never trust the bilge pump on an unattended Hunter 27 to keep her afloat under the circumstances you describe. FIX THE LEAK.

 

[Wayne Estabrooks]

More Stuff

I accidentally posted my reply before I wrote it so here goes some more. Clyde is correct, I came up with the same numbers as he did and the bilge pump would only be less than 1/4 amp hour (AH) per day and that would not drain the battery unless the battery is not fully charged to start with. Therefore I suggest you check the voltage while connected to the charger. It should be around 13.8 volts. Could be a bad battery also as one other post suggested.