Battery life

[Kenomac]

This suggestion might seem almost too obvious... When was the last time you topped off the batteries with distilled water? Are they filled?

Ken

[ontherocks83]

First thing first, get a Balmar Smart Gauge because it's a great instrument to have anyways. After that is installed see how the batteries are performing. You will then know if you have a battery issue or an alarm issue.

I know this is not a cheap method to figure out a simple problem but you may as well start to upgrade now to help you in the future.

[Cheechako]

Originally Posted by Fulmitz

They charge via shore power when at the marina 24/7. I go out maybe once a week and after an hour they drain from 13.8 to 12.4 and an alarm goes off.

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Normal new battery voltage after resting will be in the 12.45 or a little higher range.... with no draw on them. If your alarm is set to go off at 12.4 it's probably set too low.
If they discharge fast from 12.4 or so , you may not have much battery life left. But even if you replace them, the new ones are going to rest at 12.45.
BTW, if you run refrigeration very long, it will deplete batteries quite fast, definitely overnight.

[sailorboy1]

Originally Posted by Cheechako

BTW, if you run refrigeration very long, it will deplete batteries quite fast, definitely overnight.

Say What?

[Sailmonkey]

Originally Posted by sailorboy1

Say What?

Huh?!?! x2

We can run our fridge for 3-4 days without charging.......we go indefinitely with the solar panel.


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[Paul Elliott]

A low-battery warning set to 12.4V is set too high! I would want it set for 12.0V or thereabouts.

My typical refrigerator draws 5A when running. I assume a freezer would be similar. Assume a 50% duty-cycle (probably less in practice), and that's a 5A drain. If you have a 250Ah battery you should be able to go 25 hours from full-charge to 50%, at which a properly-set low-battery alarm might be triggered. Bigger battery gives you more time. More current drain gives you less time.

[model 10]

[QUOTE=Sailmonkey;1831294]Huh?!?! x2

We can run our fridge for 3-4 days without charging.......we go indefinitely with the solar panel.

What x2!? You must drink tepid beer and wine, or perhaps you sail in cool waters. In the tropics, having 12.6v in the morning is not so bad, 12.4v would have me thinking about starting the engine.

[Sailmonkey]

[QUOTE=Guy;1831334]

Originally Posted by Sailmonkey

Huh?!?! x2



We can run our fridge for 3-4 days without charging.......we go indefinitely with the solar panel.



What x2!? You must have tepid beer and wine, or perhaps you sail in cool waters. In the tropics, having 12.6v in the morning is not so bad, 12.4v would have me thinking about starting the engine.

The beer isn't tepid......but the fridge is tiny......I can keep ice cream in the freezer compartment. We did sail the tropics,and the boat is in Texas.


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[siboneysail]

Check all battery connections.

[accomplice]

Originally Posted by Paul Elliott

My typical refrigerator draws 5A when running. I assume a freezer would be similar. Assume a 50% duty-cycle (probably less in practice), and that's a 5A drain. If you have a 250Ah battery you should be able to go 25 hours from full-charge to 50%, at which a properly-set low-battery alarm might be triggered. Bigger battery gives you more time. More current drain gives you less time.

Losses from the freezer can be twice the losses from the fridge, if they are comparable size.

Different refrigeration systems work differently. Mine runs 40@24V when it is on -- but may only need to be on an hour or two a day.

[Cheechako]

Originally Posted by Cheechako

Normal new battery voltage after resting will be in the 12.45 or a little higher range.... with no draw on them. If your alarm is set to go off at 12.4 it's probably set too low.
If they discharge fast from 12.4 or so , you may not have much battery life left. But even if you replace them, the new ones are going to rest at 12.45.
BTW, if you run refrigeration very long, it will deplete batteries quite fast, definitely overnight.

re: refrigeration: 3 different boats, in the Caribe. All about the same charging required. Required about two hours running with 100 amp alternators daily at anchor. (1-1.25 hours twice a day) Boxes were small on 2 of the 3 boats, but just normal insulation.. none added.
One boat had three 4D gel batteries for the house.
One boat had 4 group 27 Deep cycle.
Cant remember what the other boat had.

[cheoah]

First thúng first. You Really need a battery mọnitor to protect your battery investment and understand your power needs. By all means check your connections, electrolyte, etc but after years of knowing my batteries status, my daily power use and production, I'd be lost without a victron or comparable. When I'm sailing offshore with instruments and nav lights I pay much closer attention to my batteries, which I can do at a glance with a monitor. They are simple to install and infinitely more effective than the forum at determining your battery status


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[zboss]

When you say that the battery alarm goes off.. exactly what do you mean? I have garmin electronics and I have only one feed to the backbone of the instruments. When the batteries are low, all the equipment turned on at once causes a low voltage alarm to appear on the instruments but this is not referring to low voltage on the batteries, but of the garmin instrument backbone. This is because I added a bunch of equipment to the backbone but have not compensated by adding a second powertap to it...

sooooo... what piece of electronics is showing a low voltage alarm?

[Fulmitz]

There is a battery monitor on the main board in the cabin salon by the charting table. There is an LCD screen that shows fuel remaining, water level in both tanks, and voltage in the domestic and engine batteries. It's a 2012 Jeanneau 44ds. I should be out on the boat tomorrow, weather permitting and see if I can get the other info such as number and types of batteries.

Rob

[Muckle Flugga]

As others have said. Battery monitor alarm is too high. Check the battery fluid levels, as likely been cooking off. Top them off, fully charge and then load test with a correctly rated load tester. Also… make sure your shore power charger has a correctly installed feedback system. Many use temperature monitors as well as charge state monitors/regulators. If yours needs one, and it is not properly installed in the correct position in the battery bank, you will be cooking off hydrogen constantly. By the way, don't smoke when playing with the batteries! And be aware that hydrogen needs adequate ventilation from your bank/box. Even if you have adequate ventilation in the box typically it is worth waiting a few minutes with a route clear from the battery bank to the atmosphere before disconnecting, as this can arc and spark.

Finally, a battery bank is like a chain: only as strong as its weakest link. If you have a bad one in series (so an example of a possible configuration in a 12v system is x2 series 6v in parallel with a second pair of x2 series 6v), even if all the rest are good, you will find holding a charge hard, and the bad one will be ruining the others. Test EACH battery after charging for final charge voltage (allow to settle for an hour or so post charging, and disconnected of course!) and then load test each. For the final voltage, all batteries in a bank should exhibit roughly the same voltage when full and disconnected or tested individually (even still connected). The final voltage will tend to drift down as the batteries age, but should do so EVENLY among the bank.

My guess, though, your batteries are middle aged at least. The previous owner may not have had the best maintenance record. Most weekend type boaters don't understand battery maintenance and are liable to have a patchy charge regimen which includes the batteries having been run down flat a couple of times at least. The latter can lead in wet cell batteries to plate sulfation, and possibly battery failure. It sure as heck shortens their life!