r25 house battery

T

terraplane

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C Dory Year
2005
C Dory Model
R-25 Tug
Vessel Name
BANJO
We were plugged in to 30amp at a local marina this weekend. Charger on, everything fine, used air cond. for a while, then shut it off...Using only house lights, radio, water pressure pump on, nothing else,...and in three hours the house battery was down...lights out, radio off.
Engine battery fine. Checked battery cables, and none loose...
80 hours on engine.

Ideas?

terraplane
 
You need to have a digital volt meter (not only portable for trouble shooting) but built in to see what the voltage is as you use power. This is only a rough estimate, but it is accurate enough to see if something is draining the batteries too rapidly. 12.2 volts is 50% discharged for a normal "lead acid battery"--at 11.8 for all purposes the battery is fully discharged and if it reaches this level many times there will be damage to the battery.

It is possaible that the fuse in the battery charger (or circuit breaker) has blow--I have had that happen several times. The battery charger power may have been off etc. With the volt meter you can be sure that the battery is charging-(13.2 to 14.4 volts). It is a good idea to check all of the circuits to be sure that there is no item which is rapidly drawing down the batteries.

Also most boats do not have adequate house banks. On my C Dories, I have added at least 220 amp hours additional battery and in one boat 330 amp hours more battery--vs the 100 amp hours which comes with the boats in the house bank.
 
Terraplane -

What Dr. Bob says is certainly true.. for some reason one of my charger fuses blows frequently - the original equipment one. While a permanent fix as Dr. Bob suggests is the best, when you are sure you're hooked into good AC shorepower, you can tie the batteries together with that emergency crossover switch to be sure all banks are charged evenly in a pinch.

I've had mine go out unexpectedly several times and there is no way to know when that happens until it is too late unless you have some type of monitoring gauge as Dr. Bob suggests. For me, the starboard charger leg blows out frequently.

John
 
Checked today and saw that there is a gfi(?) switch back near the charger and it had tripped...and i'm guessing that is one part of this...but finding out why it tripped is next?

terraplane
 
Sometimes something as simple as plugging something into the GFCI outlet with a jerky motion can cause a small spark and it trips. I was surprised when I did it but I was looking right at it when there was a small blue spark and it tripped. You might not even have a problem. Because I was on the hook a lot I always made it a habit to check the charger while plugged into power and see how the charging was going. I always used the old Newmar chargers and you could watch the needle and tell when the batteries had reached the float stage.
 
Be sure to do a thorough assessment before going off in a direction. Check the fluid levels in all of the batteries and top them off with distilled water. I found in my new batteries that considerable water was needed. Then, turn on the charger. Your tug, like mine, probably has the Blue Sea analog battery meter located under the gear shift. On mine, battery number 3 is the house battery. Anyway, watch the charging voltage for each battery bank. The charger will start high and then adjust to the needs of each battery bank. When your batteries have settled down after this charge-like in 24 hours, then do your own test of each battery cell with a hydrometer that you can get for under $10 at any auto parts store. Follow the directions on the hydrometer. You may have a bad cell. If so, those batteries are still under warranty and are widely available.

On my tug, when I thought I had a bad engine battery, I really had a very bad ground. I toasted a starter and a fuel shut off solenoid to learn that lesson. A new dedicated, super big ground from the engine block to the engine battery cured a host of small issues. The engine battery was actually fine and has been for a year and 150 engine hours.

So what you first see and think, may not be the real problem.
 
I have Hull #67. I got the electrical drawings from Andrew as pdf files & they were very helpful because the electrical system is difficult to understand otherwise. I had a few electrical problems but they turned out to be loose connections & my boat has 4 type 27 batteries (3 banks) which seem to hold up very well with charger off. The charger is a 3 step type charger with separate charging feeds to each of the 3 battery banks. The anchor windlass & thrusters have their own dedicated battery with separate isolation switch (near batteries). The house bank has 2 batteries in parellel and the engine has its own battery. The house & engine isolation switches are located in mini-cabin above the emergency parellel switch. However, be careful when you analyize problems based on info from other owners. I have noticed that Ranger appears to have changed their design configuration between models
 
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