are batteries wearing out?

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Apr 29, 2010
25
Hunter 36 nj
I have an on/off switch on my 2005 Hunter 36 which utilizes either battery 1 or battery 2. I did an overnight and started it on battery 1 and then switched to 2. I turned the toggle switch, for charging, whcih can be either 1, 2 or both to number 2. Late at night I noticed on the charger/inverter that the reading was in red so I switched to battery 1. To my surprise, it also registered red. It should have been fully charged as it was full when Ileft the slip off of the shore power. I did run both the freezer and the frig, along with GPS/autopilot. Am I doing something wrong here. Engine did start up in red zone and I motored in. Nothing in manual or inverter book. any thoughts would be appreciated. Acid level is good but I haven't cleaned terminals since I had boat. I'm going down to clean them. Maybe that is the problem but it seemed to happen awfully fast. thank you for thoughts.
 
Feb 26, 2004
23,049
Catalina 34 224 Maple Bay, BC, Canada
How old are the batteries?

How many do you have? One each or multiple batteries to make a bank?
 
Apr 29, 2010
25
Hunter 36 nj
How old are the batteries?

How many do you have? One each or multiple batteries to make a bank?
2 deep cycle Interstate cca1314 to make a bank. Was told batteries replaced in 2011. He could have used it in 2011, I bought it end of 2011 and have been using them since so they could be 2-3 years old. Guy seemed like he was honest. Also said he replaced sails in 2011 and this checked out with guy from North Sails
 
Feb 26, 2004
23,049
Catalina 34 224 Maple Bay, BC, Canada
OK, good input. How do you charge them?

Have you checked the fluid levels? Do you have a hydrometer?
 
Apr 29, 2010
25
Hunter 36 nj
I plug them into 30amp shore power. I did check the fluid levels and had topped them off with distilled water about a month ago. I don't have an hydrometer.....yet. I'm also wondering if my alternator may be going. It is an 05 and I believe it is the original in the Yanmar.
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
get a hydrometer and a multimeter that does both AC and DC (most of them do)... you can use the multimeter to test the alternator output, the shore power charger, and to test the actual voltage of the batteries, rather than a red/yellow/green meter that is mounted several feet from the batteries...
any battery can fail at anytime, but its rare that both of them would fail at the same time, especially a 3yr old interstate battery.... but one bad battery can pull the ones next to it down causing premature failure of it also.... a hydrometer is a must when you start having battery issues, as it can determine rather quickly if its a battery problem and which battery it is.....
a load tester can help also, but its way more expensive:D
 
Dec 2, 2003
1,637
Hunter 376 Warsash, England --
You THINK that when you are switched to battery 2 you are not connected to battery 1 at all. This may not be the true situation as previous workers may have bridged the two batteries by other wiring. Run a fairly heavy load, e.g. all the cabin lights, and then try a voltmeter between the positives of the two batteries when your main battery switch is 'off', 'batt 1' and 'batt 2'. Any position (except off) where there is no small voltage, eg 0.5v or more, between positives might mean they are connected. Then wire tracing is the order of the day.
Good luck.
 
Apr 11, 2010
975
Hunter 38 Whitehall MI
I'd suggest checking your battery charger too. I just experienced a situation where my autopilot starting kicking off due to low battery. Was perplexing since it happened shortly after motoring for an hour. Thought it might be the batteries but they are just over a year old. Thought maybe a defective one.

Wasn't making sense since (I though) we had just unplugged, motored and should have been fully charged.

Started diagnostics and load tested batteries. When the load was applied the charger just sat there saying everything was fine. It never kicked in to handle the drain. Put meter on the charger and it had minimal output.

New charger to the tune of 1/2 a boat unit and things are fine now.

In the course of buying new charger learned that Professional Mariner has discontinued a number of their charger models due to excessive failure rates. Ours was only 5 years old. Had a suspicion because while on vacation this summer met a couple with same boat but a year older. As we were comparing equipment and upgrades he asked me if I'd replaced the charger yet? Seems the premature failure issue is somewhat well known.

So check that out too.
 
Apr 29, 2010
25
Hunter 36 nj
get a hydrometer and a multimeter that does both AC and DC (most of them do)... you can use the multimeter to test the alternator output, the shore power charger, and to test the actual voltage of the batteries, rather than a red/yellow/green meter that is mounted several feet from the batteries...
any battery can fail at anytime, but its rare that both of them would fail at the same time, especially a 3yr old interstate battery.... but one bad battery can pull the ones next to it down causing premature failure of it also.... a hydrometer is a must when you start having battery issues, as it can determine rather quickly if its a battery problem and which battery it is.....
a load tester can help also, but its way more expensive:D
thank you all for the input. I have ordered a hydrometer and will clean the
connections and then test the fluid and go from there.
 
May 24, 2004
7,174
CC 30 South Florida
Anything can happen but chances are the alternator on a sailboat engine should easily last over 20 years. Start with the basics and determine the state of charge and health of the batteries. I don't know if it would be easy for you by I personally prefer to haul the batteries to my preferred auto parts retailer for a computerized load test. They conduct these tests for free and the printout will tell me the state of charge and if the batteries are good or not. If one battery is waek or bad replace it and if both are good then continue your diagnostics. Make sure all the connectors are clean and tight. You now need to test independently the output voltage coming from the alternator and the inboard charger. To test the alternator, first check the belt tension, use a digital multimeter and connect the positive lead to the BAT terminal and the negative lead the the E terminal, at this point you should get the normal battery reading of around 12+ volts. Wiggle the engine wire harness, if the reading remains steady the harness is ok but if you see voltage drops then the connectors maybe loose or dirty. Turn the engine on and rev up to 2500 RPM the meter should read between 14.2V and 14.8 V. If the reading is outside these parameters remove the alternator and have it bench tested. To test the inboard charger may require to draw down one of the batteries a little then test the output voltage of the charger at the leads to the battery. Once again voltage should be 14 volts or over. The other possibility to your problem is that batteries can only charge at their acceptance rate. The refrigerator and the autopilot can be high draw items. A refrigerator that is not precooled and an autopilot in rough conditions can quickly draw a battery down which will take a few hours to recharge. When on the go and on the hook it is quite common to undercharge batteries as we do not want to spend the extra hours to charge from let's say 90% capacity to 100%. Batteries which may be continuously undercharged will start sulfating and their capacity will be diminished and their useful life shortened. If I were a betting man I would say your batteries were already probably weakened. If the alternator and battery charger check OK but if the ability of the batteries to hold full charge is impaired I would consider replacing them and start them on a health regime. Allways recharge them to 100% or to a voltage of 12.67V at rest and avoid discharging them past 50% or a voltage of 12.20V. Help them along by precooling the refrigerator before casting off. Preccool at high and then adjust the thermostat down. There are a few tricks to keep power consumption down on refrigerators, pack frozen items, a full refrigerator is more efficient than a partially full one. Do not open the lid frequently or unnecessarily and for that reason well pack the beer and drinks in an ice cooler. Good luck, hopes this helps.
 
Dec 19, 2006
5,832
Hunter 36 Punta Gorda
Batteries

I agree start with checking out the batteries before thinking anything else wrong,I have same boat but different setup with inverter/charger and 2 4D's.
One of the batteries went bad first year and both went bad in 2012 and now have 4-6volt one big bank no more switching between batteries.
Most likely at least one or 2 are not charging proberly.
See which is bad if 1 is only bad and than save the one good for starting battery and get 2-6volt for one nice size bank and than no guess switching batteries,that's what I would do but that's me.
Nick
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
one thing to keep in mind when checking the shore power charger, depending on the style of charger, it may take several seconds to kick in and when it does it may not jump right up to maximum charge on your test meter.... but the voltage will slowly climb over several minutes to maximum charge rate. this is normal as its sensing the needs of the battery and delivering the required charge at batteries potential, rather than the chargers potential.

and at the alternator, if your batts are low you will see the high voltage output, but if the batts are fully charged, you may only see about 13.2volts from the alternator....
but either way, when you have the engine off with the multimeter connected to the batts, when you start it you should see an immediate jump (within 3 seconds) in the meter even at an idle...... if your batts are fairly low and you dont see 14+ volts output from the alternator when the engine is running at a fast idle, the alternator is probably the culprit..
 
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