batteries

[rwilkinsii]

I just put 4 new group 27 dual purpose batteries in my boat per the Surveyor's suggestion. I am seeing allot of people going with the golf cart batteries instead of getting the group 31 deep cel or even the group 27.

I was told the dual purpose is kind of like deep cell batteries but are able to crank the engine with just one battery. This is all new to me as i have just bought the boat about 2 months ago.

Any help would greatly be appreciated (sp)

Thanks

Rich Wilkins
Houston Tx
86 c34
S/V Lil Tiger
Geaux Tigers!!

[This message was edited by Rich & Stacy Wilkins 86 # 65 Lil Tiger on October 09, 2003 at 08:23 PM.]

[Mike Smith]

Rich -

I'll give this a shot although I'm sure one of our resident 'trons has a better understanding of batteries than I do.

Starting batteries provide a lot of power for a short period of time, i.e., starting an engine.  By the nature of their construction (thin plates) they can be recharged rapidly but do not have a great amount of amp hour capacity.  They are not intended to provide power for a long period of time and should not be repeatedly deeply discharged.

True deep cycle batteries are intended to provide power for a long period of time. By the nature of their construction (very thick plates)they can be repeatedly deeply discharged and have substantial amp hour capacity.  They are available in 6-volt versions which can be wired in series to provide the same capacity at 12 volts.  They are called "golf cart" batteries because that is one highly visible, popular application of this type of battery. The "golf cart" battery commonly used on our C34s is the Trojan T105. It is not really a "golf cart" battery (Trojan has another battery series for that) but is used in alternative energy applications to store electricity at remote solar or windmill driven applications. Four of them fit perfectly in the C34 battery compartment, and if paired in series and then connected in parallel, provide about 440 amp hours of 12 volt DC. This is the setup I have and I am very pleased with their performance. Here is a link to the Trojan Website: Trojan Batteries

Marine "deep cycle" (dual purpose) batteries are a compromise between the two. By the nature of their construction (sorta thick plates) they can be repeatedly discharged but do not have the equivalent amp hour capacity of true deep cycle batteries.

I recommend getting true deep cycle batteries for your house bank and installing a separate starting battery for your engine after your new group 27s turn belly up in a year or so.

This is a very simplistic explanation of the differences among battery types as I understand them.  I'm sure others will expound further.

Mike

Mike and Jan Smith
S/V Breezer
www.mikejansmith.com

[This message was edited by Mike & Jan Smith "Breezer"  '88 #688 on October 10, 2003 at 06:37 AM.]

[Stu Jackson]

Batteries

Mike's description was exactly correct.

Thanks, Mike, for writing that.

Rich, PLEASE, go buy Nigel Calder's book and read it.

It'll save having Mike and others type in stuff that has already been written to answer exactly the questions you are bringing up, and are likely to have in the near future.

Stu

[rwilkinsii]

Thanks for the response. I am going to get the book this weekend.

Rich Wilkins
Houston Tx
86 c34
S/V Lil Tiger
Geaux Tigers!!

[BillR]

Where do you keep your boat in Houston?

[rwilkinsii]

I keep it at Watergate Peir 7 slip 50. I will be there this evening and on sundays around noon for the next 3 weeks then i will be there every weekend...  (football season)

Rich Wilkins
Houston Tx
86 c34
S/V Lil Tiger
Geaux Tigers!!

[John]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Stu Jackson #224 1986 "Aquavite":
Batteries

buy Nigel Calder's book and read it.
<HR></BLOCKQUOTE>

Which book, he published several.

[Stu Jackson]

John,  

Boatowner's Manual for Mechanical and Electrical Systems.

His newer Cruising Handbook is a lot of repetition. Got it from Santa last year, so fun reading.   I'd only recommend anyone spending money on it if they keep asking about prop walk :rolleyes:  He has a very good description.

If I only had two books to take with me, those two would be the ones.  (I'd still sneak a Maurice Griffith book in, though: "Magic of the Swatchways".)

Stu

[This message was edited by Stu Jackson #224 1986 "Aquavite" on October 15, 2003 at 10:54 PM.]

[rm_fleming]

"Minor Infraction" came to me with two group 27 batteries.  I went with a very simple upgrade.  I replaced one of the 27's with a D-4.  The D-4 has at least 3X the capacity of a gp. 27, maybe more.  It is a 12 Volt making the change simple; and fits easily next to the remaining group 27.  The D-4 is now my primary house battery.  Works great.

[Capt Gus]

I have a question for Mike: Do you have a starting battery in addition to the four T105's?  Also, how big an alternator do you use to charge them?

[Mike and Theresa Vaccaro]

Interesting article on Sailnet recently:  Called "Pluses and Minuses" by Don Casey.  Does a very good job of outline battery budget/system requirements--including alternator sizing.  Bottom line on alternators is that there is a practical limit imposed by the engine (i.e., the horsepower required to run the alternator) as well as a practical limit of the amount of charge a bank can except (rule of thumb is 25% of capacity--e.g., 440 Amp hour bank = 110 AMP alternator, any excess is wasted).

If your typical boating is limited to day sailing with the occasional overnight, if you size your battery bank for 48 hours of autonomous operations (i.e., no charge of any type)--you're fairly well covered and need not consider much in the way of modification other than adding the appropriate batteries.  Your best bet is to reduce consumption vs. "upsizing" capacity (this is a simple function of physics, unfortunately there is no free lunch).  If your needs exceed basic systems, you may need to consider alternative power sources--the only one with nearly 99% reliability is a genset.  If your requirements are modest, a solar system might be just the ticket.  

An odd-ball, middle of the road solution is a large-capacity engine-driven alternator.  An example is a "SeaPower" system (currently marketed under the brand name Mobile Electric Power Systems).  These are actually designed for emergency response vehicles as a source of AC Power.  We have a 5KW system that provides AC power when the engine is running.  This allows us to charge our house bank using the AC-powered three stage charger, very efficient.  But the downside is that you've got another system to maintain and the SeaPower is actually designed for a large, high-horsepower engine and severly taxes the small 23HP M-25 in our boat.  We can only run it at speeds above approximately 1500 RPM, and it takes 2.5HP per KW of power produced.  This system represents a compromise between a true genset and no self-contained AC power source.

Cheers,

Mike Vaccaro

[Stu Jackson]

Mike, you make very good points about acceptance and alternator sizing.  Please note that a 75 to 90 amp alternator is about as large as would be recommended for our engines (older ones, at least) and, with the 25% rule for wet cells, still be able to maintain a house bank of 400 amp hours.

While there hasn't ben a specific "electrical systems" thread or Projects or FAQ on our site, there have been some long threads about batteries, chargers, alternators and systems.

A good starting point is:

http://c34.infopop.cc/6/ubb.x?a=tpc&s=329609511&f=829605811&m=654602911&r=964602911#964602911

If you use the find feature of the message board, you can hunt up lots of very good information.  To find the link above, I used "electrical" - try batteries, chargers, and alternators, too.

In addition to Don Casey's book that Mike mentions, Calder's Boatowner's Manual is invaluable in designing and maintaining electrical systems, as well as trying to learn about what you already have on your boat.

Now that many of the first generation boats are turning over to their third and fourth owners, electrical systems should be a great winter study issue.  It could well be that many of the older boats hav not been upgraded electrically.  

Also, even the newer boats coming out of the factory do not have externally regulated alternators, just the same old 55 amp Motorola or equivalent.

Happy Electrons!

Stu

[paule]

I am sitting here reading about the batteries and replacements for the batteries. I do have some concerns, a friend of mine a couple of slips down also owns a 2000 C34 and has to repalce his batteries next season. Since this is my first season with my 2003 C34 I am wondering will I also be replacing mine in three years. Sould I be thinking of replacements?

Paul

[Norris Johnson]

Paul,
I had the same problem with my batteries, but the problem wasn't with the batteries, it was the charger. It is a 20 amp Flyback and it was overcharging the 2 4d's that came with my boat. I sent the charger back to the factory and it was repaired. The cost of repair was related to the age of the charger. It was ~ 75 bucks.

[paule]

How do I know if my charger can cause the problem is there a serial # or a rcall on the charger. I heard of problems on some of the 2000 boats C36's in particular.

Paul