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Tenedos · 03-06-2016, 09:29

Ahoy sailors,

I am having an issue with my batteries and shore power charger and not sure if this is normal or how I can troubleshoot.

I have two batteries onboard my Catalina 320. Both of them came with the boat when I purchased her 3 years ago. They are both flooded acid batteries.

I suspect #2 is about 3.5-4 years old, not sure about #1. #2 started giving me problems, not holding charge. I kept it connected still, which may not have been the right move at hindsight. I am looking for a replacement for #2 but haven't done it yet. I am mostly on shore power at the dock.

What I noticed is that when I am at the dock on shore power, my charger keeps running and running. It almost never stopped (I can hear the distinct but subtle noise that it makes while charging). I started getting worried about it, thinking it would ruin my working battery #1 too. So this morning, I disconnected #2. So I only have #1 connected now.

This changed the behavior somewhat but didn't alleviate my concerns. Here is what happens: I can hear the 'charging sound' for about 2 minutes, then it goes off for about 1 minute and it comes back. It keeps continuing in this cycle.

To make sure it wasn't my fridge or anything else that was needing it, I turned off the DC altogether on the boat, so nothing should be sucking electricity out of the battery right now. Not sure what could be triggering the charge.

I am a little worried and debating what to do.

Should I leave it to run like this, hoping it will correct itself when it gets a full charge? Or should I disconnect shore power/turn of battery charging switch until I get replace #2? Is it possible my charger got damaged along the process?

Suggestions or pointers will be appreciated.

Thanks,

Beausoleil · 03-06-2016, 11:53

Can we assume that you don't have a voltmeter on your DC panel?

First thing to do is to check the electrolyte ("water") level in #2 and make sure the plates aren't exposed - the electrolyte should reach the bottom of each of the six battery cap openings. Add distilled water if they're low.

The humming of the battery charger may simply indicate that it's float charging (holding the voltage across the battery terminals) at the normal ~13.8V (@ 70 degrees F). Get yourself an inexpensive digital multimeter (DMM) that displays up to hundredths of a volt (2 digits after the decimal point) and measure the voltage across the battery terminals. If it's less than ~13.8V then either the charger's in bulk charging mode, or there's an internal short between cells in the battery.

As a battery charges, its internal resistance increases, so a smart battery charger will continue to charge, raising the battery's voltage to about 14.2V. This is the beginning of the "absorption" phase of charging. Depending on the sophistication of the charger, it will hold that voltage for up to 6 hours, or (if it's really smart) will maintain that voltage until the current being pumped into the battery reaches about 3% of the battery's capacity. I.e., if you have a battery rated for 100Ahr, once the current being pumped into the battery drops down to 3 amps, then it's considered charged, and the charger switches to float ("maintenance") mode.

If the charger stays in absorption mode too long, the electrolyte will eventually boil off, harming the batteries.

The assumption on your part that the charger is cycling on and off may be normal, depending on the charger model. It may be its method of "maintenance" or "battery-saver" mode.

Tell us the make/model of your battery charger (and the batteries, if possible), and we can help you further.

Tenedos · 03-06-2016, 14:41

Thank you for the very detailed response Beausoleil, very valuable not only for this question but for future reference as well.

I have since replaced #2 with a dual purpose flooded acid (4D) battery, literally 15 minutes ago. It is branded Energy Power (I think it is a generic brand, from Battery Specialists). I had checked the electrolyte/water level on the old one before, it was not low.

With the replaced battery, I can hear the continuous humming from the charger now, it doesn't go on and off, it is continuous.

My charger is Promatic 30-3. On the gauge, I read about 18-19 amps.

My voltmeter on the DC panel reads just a tiny bit higher than 14 volts for both batteries when the battery charger is on. When the charger is off it reads just a bit higher than 13 volts for battery #1 and about 13 volts for battery #2 (the new one).

I am curious if the charger will go off after a certain period, or it will keep going.

exMaggieDrum · 04-06-2016, 15:45

Could you indicate how the batteries are wired? Are the wired together all the time or separated by a selection switch? Does you charger have two charging circuits, i.e. can charge more than one battery at a time? Are both batteries for the same use or separate, e.g. both house and engine start batteries or one is for start and the other for house? Is there a battery charging solenoid to charge one battery once the first battery has a high enough charge?

BTW - these types of issues are some of the most common on boats. You are not the first one. The solution will be different though depending on what you have.

In general you only want to connect batteries together that are the same type, age, and condition. One bad battery can kill the other otherwise.

Sounds like yours are separate but if you put your battery selector switch to "all" all of the time, then you have really connected them together for good or bad. This is commonly done when the charger is only set up to charge one battery at a time.

Tenedos · 04-06-2016, 16:44

Thanks exMaggieDrum.

I have a selection switch, I can switch to either #1/#2 or both. I honestly wasn't aware that selection changed how the batteries are charged. I believe charger still charges when I put the switch in off mode too. So which one would it charge in that case (switch is off)?

The one I replaced (#2) was a deep cycle battery. I replaced it with a dual use one as I don't know how long #1 will last. I wanted something that I can use to start the engine if #1 goes bad too. I got both of the batteries with the boat 3 years ago. So they must have at least 3.5-4 years more on them.

I understand the ideal scenario of having identical batteries. But having just replaced #2, I don't want an additional expense to change #1 too. If it goes for another year or two, that would be great.

The humming has been going on. After reading your message, I changed the switch to #2 from both. I can still see the humming of the charger. It hasn't stopped for last 4-5 hours since I came to the dock.

I will let it go for another 2-3 hours but if it doesn't shut off, I am thinking of killing it with the charge switch.

Do you know what is the maximum 'normal' time for the charging to go on? Should I wait 12 hours or potentially more before stopping the charging?

Cheechako · 04-06-2016, 17:28

It sounds like one of your batteries has a shorted cell. Feel the side of the batteries with your hand, Is one hot and the other not? separate them and remove all loads overnight. The shorted one will be totally dead and the other not.
It's also possible a post has wet corrosion , you cant see it, it's inside the clamp, but when you remove the clamp you see it's wet.

exMaggieDrum · 05-06-2016, 08:43

Tenedos,

One question is whether your charger is actually charging when it is humming or just humming. If you have an ammeter on your house panel, or a multimeter display, you can check the amps that are going to the batteries (depending on how it is all wired). What happens when you charge a down battery is that the charger starts sending amps of electricity to the battery until it reaches a set voltage max that is usually set at the charger. Some very old chargers were not settable to different voltages but yours does I'm pretty sure. If no amps then no charging going on even if it is humming. When you check that make sure the other users of the batteries (lights, radios, other) are off. If you have anything else on you will see the net of the two (one minus and one plus) so it is more confusing so it helps to simplify the test. If the batteries are already at the set point of the charger there shouldn't be any amps going to the batteries.

You should take out the operation manual for your Procharger and read it carefully. It will have a wiring diagram and instructions and at least a brief troubleshooting guide. The wiring diagram will show the recommended wiring on the positive side but there are many workable variations. Like I mentioned the charger leads are often direct to the batteries but sometimes they are to your battery switch since that is sometimes easier to do (or not). What you want to understand is how the charge wires are wired. I recommend following them from the charger to where they go and make a rough diagram (useful later).

I would also trace the wiring to the battery switch between each battery to the switch. This will educate you on how it is wired. I have seen battery switches wired in some different ways but usually they are not complicated with only one switch. Some boats have a start battery switch plus a house battery switch so you can turn them on or off independently.

I would bet that yours are wired to a what is called a 1-2-All switch. There would be two inputs on it labeled "1" and "2" on the back of the switch. Note that the posts don't match up the same way to the labels on the front label, i.e. the "1" battery post will probably not be just opposite the "1" on the switch label on the other side. It helps to be able to actually see the back of the switch if you can. There are ways to avoid looking at that to figure out how it is wired with a voltmeter but you have to be consistent and each battery has to have a different voltage when you start.

Your would turn off the battery switch, wait for 15-20 minutes and then measure the voltage of each battery at the batteries themselves. Write that down. Then turn the battery switch to "1" and see what you voltmeter on your house panel says. Also measure it at the starter solenoid. If the voltages match the voltage of one of the batteries then you know which one is number "1". Mark that on the battery and on your wiring diagram. Then confirm the "2" is for the other battery.

If you have any strange readings then there is probably some other wiring that is mixing things up. You'll need to get someone who know how to do this stuff to trace all the wiring to see if the batteries are actually combined via some other wiring other than the battery switch. You really want the batteries to go only to the switch first and nowhere else. Except, one battery may be hard wired direct to the starter. It would be your start battery. Label that on your diagram. You would then have two big cables going from the start battery - one to the switch and one to the starter. The other battery would be your "house" battery. It would not have a direct wire to the starter.

Your charge wires could go direct to the batteries but sometimes goes to the back of the switch on the same post/connectors for each battery. I think your charger can actually charge 3 batteries at once but if your is wired "best" it would have two output wires, one for each battery. The third output would not be used (no wire).

So you would not need to turn the battery switch to "all" to charge both batteries if wired the ways I mention here since a separate wire for each would go direct to each (either via the battery switch post or direct to the batteries). I have seen, and don't like, when the charger goes to the "output" connector on the back of the switch. It is usually labeled "C", for "common". If the switch is set to "1" then the "C" connector is "on". If the switch is set to "2" then the "C" is "on" but only for battery 2. "All" combines both batteries so they are combined at "C". This is useful if you have two good batteries but they are not individually strong enough to run the house or start the engine. The starter can either be wired to the "C" on the switch or direct to one of the batteries (your start battery).

I have to run - I will look for a simple diagram to show all this online. There are some available. I have to get out to meet someone.

Beausoleil · 06-06-2016, 13:37

Tenedos,

A little bit of Google-** turned up the manual for the charger here. It's an older 3-bank, 30A, 3 stage (bulk/absorb/float) charger with a built-in ammeter.

exMaggieDrum had some good advice above. Your charger should have been wired so that each of your two batteries has it's own + charging cable from the charger, so no need to select BOTH on your battery switch when charging - if that's how it was wired in. The installer may have been lazy and just run a single cable to the C (common) terminal on your battery switch, but it sounds like you think its been wired correctly.

The Promatic has voltage settings for either FLA (flooded lead acid) or gell batteries, You should probably confirm that the dip switches are set for FLA. The charger will run thru its charging cycle as I explained in my first response. It will not shut down when it finishes charging - it will switch to float mode as long as AC power is applied.

You mentioned earlier that you bought a new dual-purpose battery and commented about how the other was a deep-cycle - I wouldn't worry about that. You shouldn't mix battery types within a battery bank, but what you have is essentially two battery banks, each containing a single battery. I personally would have bought another deep-cycle battery. You can easily use a deep cycle battery to start the diesel engine of a Catalina 320 - no problems there. But using a dual-purpose battery to run house needs like lights and electronics will not be the optimum thing.

Badsanta · 06-06-2016, 14:49

It's hard for a charger to figure out what full is when other devices are sucking out amps at the same time as the charger is putting them in.
Like trying to fill your tub with no drain stopper.

Stu Jackson · 06-06-2016, 14:58

Would you please share with us what brand and size charger you have?

Tenedos · 07-06-2016, 11:55

All, thank you so much for your responses and help. I think my problem is solved by following Cheechako's recommendations. I took the clamp out for battery #1 and used a sand paper to clean it up. I think there was some corrosion on the connector.

Doing so and waiting for another couple of hours did solve the problem.

Once again, I really appreciate the help and advice everyone has shared. Boat ownership can be daunting f you don't know what you are dealing with and the community support offered here makes it much more manageable.

**tkeithlu** · 07-06-2016, 13:41

You've gotten wonderfully detailed advice from very knowledgeable people above. Let me add a low tech reliable way of making sure that you're not simply dealing with a bad battery. A $22 battery load tester from Harbor Freight, applied across the terminals of a supposedly charged and definitely isolated battery, will tell you that the charge is at 13.4 v, or whatever, and then in a few seconds of load (a resistance coil that gets very hot) whether the battery can hold a charge. You can borrow one from any friend who does his own automobile maintenance. Having nine batteries and two major charging systems, I keep one in the engine room. As one of your mentors above says, one bad battery can damage the rest of your bank.