Battery life

[Fulmitz]

Ok, so I have a 2012 Jeanneau 44DS I bought last July. Now sometimes when I go out I like quiet so I don't turn on the generator. After an hour of sailing the battery alarm goes off warning low voltage. I'm not running A/C, the lights are off. The only thing on are nav instruments, the refrigerator and freezer. Would that run down the batteries so fast? The other thing is the charge battery switch was left on. Could it be the inverter is using the battery power to try and charge itself and its running itself down? Could I just need new batteries?

Thanks,

Rob

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[Sailmonkey]

You won't be trying to charge the batteries from the batteries.......unless something really odd has been done.

But it would be good to know how many batteries and what is their ah capacity. Also what is your current draw while sailing.
Have you been maintaining your batteries (adding water when needed) or are they sealed?


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[St. Elsewhere]

The refer and freezer are definitely a significant drain on the batteries. The key to long battery life is to keep them charged and to not discharge too much before charging again. If you recharge at 50% you will have good longevity. A rough measure of the 50% mark is 12.2 volts on a 12 volt lead acid battery, and 24.4 volts on a 24 volt system. If you deeply discharge, and leave them at low charge, you will be replacing them often.

[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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[Sailmonkey]

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.

Sent from my HTC One_M8 using Cruisers Sailing Forum mobile app

How many are "they". How big are "they" how are "they" maintained?


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[JstaRebel]

You can test your batteries with a battery load tester that is readily available at any auto parts store to see if they are bad. Second is to do the proper calculations to see what you need regarding amperage per day. The link is for an amperage calculator. Marine & RV Battery Load Calculator from Boundless Outfitters . Last is installing a cheap inline power analyzer to keep track of your battery drain. Having this device also gives you a tool to use for checking for battery drain from unknown sources. DC Inline Watt Meter and Power Analyzer, Powerpole Ends [WattMeter-PP] - $49.99

Hope this helps, and good luck!

[S/V Illusion]

It certainly sounds like one or more batteries has "seen better days", however, never make snap judgments. Start with the easy (and inexpensive stuff).

Have you removed, cleaned and reconnected every connection at every point in the charging circuit including batteries, panel and engine?

If not, these symptoms could be a bad or high resistance connection.

[jeepbluetj]

I assume flooded lead-acid.

IMHO, if your charger is holding them at 13.8 (or higher), those batteries have been boiling away. If that 13.8 is from running the engine, that's OK.


As others have said, test them. If they're bad, you may wish to investigate your charging system if it is overcharging. That'll kill batteries pretty quickly.

[Snore]

Absent an amp meter you are shooting in the dark.

IMHO set the boat up right. Balmar smart gauge across both the start and house banks then a Victron 700 on the house. You will then know for sure what is going on.

I just finished doing this on my boat, and it already paid for most of the DIY cost. My panels were not putting out at the rated capacity.

Or you could load test the batteries and hope you don't have a bad connection or foreign ground or ....

YMMV


..

[St. Elsewhere]

So just to summarize . . . .

1. A battery load tester will tell you if new batteries are needed.
2. An automatic multi-stage charger will apply correct bulk and float charge rates at your dock and when running your gen set. Your bulk charge voltage can be 13.8 and diminish as the charge increases. The float voltage should be 13.2 volts. More info is here.
3. Instrumentation such as a battery monitor, volt meter, and ammeter will let your observe conditions.
4. Investigation of the connected loads and battery capacity will tell you if you have a large enough battery bank.

[cabo_sailor]

Something to consider is that most battery load testers are not rated for hi amp/hr ratings. My house bank consists of 2 200 amp/hr 4D batteries. Most of the load testers are rated for only 100 amp/hr.

It's definitely an $$$ ouch but I just replaced my 4D AGM house bank and 2 Group 27 AGM Engine batteries for about $2 K. Battery access is terrible so I'm stuck with AGM.

Rich
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[Snore]

Originally Posted by St. Elsewhere

So just to summarize . . . .

1. A battery load tester will tell you if new batteries are needed.
2. An automatic multi-stage charger will apply correct bulk and float charge rates at your dock and when running your gen set. Your bulk charge voltage can be 13.8 and diminish as the charge increases. The float voltage should be 13.2 volts. More info is here.
3. Instrumentation such as a battery monitor, volt meter, and ammeter will let your observe conditions.
4. Investigation of the connected loads and battery capacity will tell you if you have a large enough battery bank.

Note that having a good amp meter as noted in step #3 will allow you to have real connected load data versus assumed.

If the cold plate is reported to create a 70 watt load, but the compressor or motor is tired, it may draw 80-90 watts. In my case the PO added a blower to move heat away from the compressor. While this may have helped the compressor, it significantly increased the unit's electric demand. I am now looking at some type of chimney to passively move the heat away from the compressor (long story).

Just say'n.

[sailorboy1]

Originally Posted by Fulmitz

Ok, so I have a 2012 Jeanneau 44DS I bought last July. Now sometimes when I go out I like quiet so I don't turn on the generator. After an hour of sailing the battery alarm goes off warning low voltage. I'm not running A/C, the lights are off. The only thing on are nav instruments, the refrigerator and freezer. Would that run down the batteries so fast? The other thing is the charge battery switch was left on. Could it be the inverter is using the battery power to try and charge itself and its running itself down? Could I just need new batteries?

Thanks,

Rob

Sent from my HTC One_M8 using Cruisers Sailing Forum mobile app

What was the state of charge when you started? How do you know?

I can sail with the same loads for a day before my 460AH house bank gets to the 50% SOC if they started at 100%.

[skipmac]

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.

Sent from my HTC One_M8 using Cruisers Sailing Forum mobile app

First, as others have said, need to know how many, how old and what kind/size batteries you have to give a really meaningful answer. But a few comments.

1. Batteries showing 13.8V are showing residual voltage from charging. Battery voltage will never be that high in their normal state. If you disconnect the charger for a few hours and have no load on the batteries the voltage for a good, fully charged FLA battery should be around 12.6-12.7V

So the initial voltage drop from 13.8 to 12.4 the majority of that is just losing the residual charging voltage.

2. 12.4 volts seems very low for a battery alarm to go off. Even fully charged batteries in new condition might show 12.4V after a short while with a significant load (like a fridge/freezer)

3. Agree that you need to check all the terminals, connections, etc to ensure they are tight and uncorroded. This could cause the alarm and any number of other problems.

[sailorboy1]

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.

Sent from my HTC One_M8 using Cruisers Sailing Forum mobile app

Probably not a battery problem, sounds more like an alarm problem (set way too low)! My batteries under sailing and refrigerator load will go to 12.4V within a couple of hours and the batteries will still be 90% state of charge.