Battery Charge

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tim_farrell
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Battery Charge

I spent a good part of the day on my mooring on Saturday replacing my old solar vents with new ones. I was there for about 6 hours in all and had the batteries running the whole time. I left the boat, leaving the batteries on because I was planning on returning for an evening sail (I wanted cold beer!!).

I was gone for about 2 hrs. Upon my return, the kids wanted to swim before heading out and we ended up sitting at the ball for another 90 min. All in all the batteries were engaged for about 9.5 hours.

You guessed it, the boat wouldn't turn over when I went to start it. I took two of the three batteries home and charged them overnight - came back in the AM and she started right up. I then motored around for an hour to ensure the 3rd battery charged.

Is 9.5 sufficient to drain your batteries? I rarely use my motor - only enough to get to open water (10 min) to get the sails up. I am contemplating a routine of running the engine for 1 hour every other time I go aboard - just to ensure a full charge. Any one have this happen? Am I thinking about this correctly?

Tim Farrell
S.V. Kailua
C36 - 1986
Hull# CTY0678A886

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Chachere
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[QUOTE=tim_farrell;9440]
You guessed it, the boat wouldn't turn over when I went to start it. I took two of the three batteries home and charged them overnight - came back in the AM and she started right up. I then motored around for an hour to ensure the 3rd battery charged.

Is 9.5 sufficient to drain your batteries? I rarely use my motor - only enough to get to open water (10 min) to get the sails up. I am contemplating a routine of running the engine for 1 hour every other time I go aboard - just to ensure a full charge. Any one have this happen? Am I thinking about this correctly?[/QUOTE]

9.5 hours shouldn't be enough to drain your batteries, even in this weather. We have 225 amp hours in our house bank (2 6v golf cart batteries) and it seems to take about 2 days to draw them down to 50% with the fridge running and careful use of lights, etc.

The bigger question is why your starting battery went dead, since it shouldn't have been hooked in to run your fridge. ... You are wired to isolate it from the house circuit, no?

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

pierview
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Posts: 606

Batteries are pretty much of a mystery to me but, most diesel people will tell you to run your engine not "under load" for an extended period is not good for the engine. An engine is much more expensive than a battery.

Chuck Parker
HelenRita 2072 Mk II
2002 Tall Rig - Winged Keel
Atlantic Highlands, NJ

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ProfDruhot
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Posts: 354

Tim, I guess my question is, how are your batteries wired? Do you not have a dedicated battery for starting only? If not, you may want to consider changing them over; that way you will not have to worry about starting the engine to get out of nasty weather. Regarding the question of running the engine to charge up your batteries, I have always heard from diesel experts that it is best to run the engine under a load.

Glenn Druhot
Carpe Diem
New Bern, NC
35* 6' 10" N / 77* 2' 30" W
2001 C36, Hull #1965
Std Rig; Wing Keel; M35B

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tim_farrell
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Thanks for the advice about not running the deisel under load. I had heard that before - but got focussed on the short term problem - thanks for helping me see the bigger picture.

No, I don't have a separate battery for starting. All three batteries feed both house and the starter. Sounds like I should re-configure. Should I consider a different type of battery for each purpose? All three are deep cycle marine batteries at the moment.

tim

Tim Farrell
S.V. Kailua
C36 - 1986
Hull# CTY0678A886

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TomSoko
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Posts: 978

Tim,
If your current batteries are all deep-cycle, the simplest and easiest way to go is to combine them all into one house bank, and then add a dedicated starting battery, that is NOT a deep cycle. Any regular car battery would do fine. Have the alternator output go directly to the house bank, and get an echo charger to take care of charging the starting battery. You could even use the existing 1-2-B battery switch. Use the house bank for everything, and then if you have a problem, you will have the starting battery in reserve. Let me re-phrase a couple of the double and triple negatives in previous posts. You SHOULD run a diesel with a load. Just charging the batteries at high idle is not a good thing to do with a $8-10k diesel engine. You would be asking for problems in the future. A bigger question is why you ran out of amps after only 9-10 hours. Something is wrong. Are the batteries old and tired and about to die? Have you cronically undercharged the batteries, shortening their lives? Do you have some big energy drain you are not aware of? Even bigger question is do you have some type of battery monitor so that you know what's going on, rather than guessing??? Many owners have installed the Link 10 and been happy with it (now the Link Lite or Link Pro?) With the stock alternator/regulator, it would take MANY hours of motoring to bring depleted batteries back to life. Lots of things to consider. Your boat, your choices, your money!

Tom Sokoloski
C36/375IA Past Commodore
Noank, CT

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stu jackson c34
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Posts: 1270

Tom's right. If you would like a "primer" on boat electrical systems, try this: Electrical 101: [url]http://c34.org/bbs/index.php/topic,5977.0.html[/url] from this "101 Series" of topics, [url]http://c34.org/bbs/index.php/topic,6437.0.html[/url] You may also want to consider a solar panel.

Stu Jackson, C34IA Secretary, C34 #224, 1986, SR/FK, M25 engine, Rocna 10 (22#)

borregomark
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Posts: 33

I lived on a mooring for 5 years. It seemed the batteries were always flat due to undercharging. A standard alternator and regulator would take 5-6 hours to bring the batts back up. I had to supplement charging with a 2000 watt Honda generator. They are very quiet and fuel efficient. It will run the microwave and all of the Christmas lights while watching a movie during the evening recharge. The other posts did a great job stressing the importance of keeping the batteries charged. They don't last long when undercharged.
Good luck!

Mark Andrews
S/V Grace
86 C36 #995730
San Diego

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deising
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Posts: 1351

The whole subject of batteries and charging is a LARGE chapter in a book.

But, IMHO running the engine on the hook or mooring to use the alternator for charging is not something you want to do on a regular basis. Getting set up with solar panels and/or wind generator is an expensive option, but worth it for the long term if you anchor out a lot. Alternatively, having a small, quiet portable generator is another option, but requires you to carry more gasoline than perhaps you want to.

As for your statement, Tim: "I am contemplating a routine of running the engine for 1 hour every other time I go aboard - just to ensure a full charge." That will never ensure a full charge for the reasons others have stated.

Good luck with your choices.

Duane Ising - Past Commodore (2011-2012)
s/v Diva Di
1999 Catalina 36 Hull #1777
Std rig; wing keel, M35B, Delta (45#)
Punta Gorda, FL
http://www.sailblogs.com/member/diva-di/

Maine Sail
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Posts: 324

[QUOTE=tim_farrell;9440]

Is 9.5 sufficient to drain your batteries?[/quote]

That question can only accurately be answered with more data. The obvious answer is no but it all depends upon the age and condition of the batteries and what was running. For example if you had the fridge going with an inverter running a laptop and some instruments you could be approaching 10 amps per hour or 95 Ah's...

[QUOTE=tim_farrell;9440] I rarely use my motor - only enough to get to open water (10 min) to get the sails up.[/quote]

And here's the problem. With 10 minutes of charging your probably replacing very, very little. Lets' say you have the stock 55A alt that will put out about 45-50A max. So now you run it for ten minutes in bulk and you get only about 8.3 Ah's returned. But you go racing/sailing and use 10 Ah's so now your battery is constantly giving up more than you put back. Your bank could have easily been at 45-50% state of charge before you ran it for 9.5 hours..... Also that ten minutes is not necessarily good for the motor as it usually takes longer than that to burn off the internal start up condensation.

A battery monitor is a GREAT TOOL!:D

[QUOTE=tim_farrell;9440]I am contemplating a routine of running the engine for 1 hour every other time I go aboard - just to ensure a full charge. Any one have this happen? Am I thinking about this correctly?[/QUOTE]

It appears you're on a mooring and should really contemplate a solar panel and charge controller for the way you're using the boat...

-Maine Sail
https://www.marinehowto.com/

 

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tim_farrell
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Posts: 117

Thanks everyone for the great information. I have a lot to learn about this subject still.

I plan on moving to a split battery configuration, one for starting and a bank for the house. I also think the value of a high quality monitor is worth the investment. I will plan on adding over the winter.

I also appreciate all the thoughts on creating a power budget. After all of the reading I have done here - I realize I have no idea how much power I spend each time I am on the boat. Thanks again.

Tim Farrell
S.V. Kailua
C36 - 1986
Hull# CTY0678A886

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