Replacing batteries & equalizing batteries

[westcoaster1358]

I have 4 golf cart batteries, they are not holding a complete charge.  I am going to replace them.  They are wired two (2) together and two(2) together, or I can switch them all on.( bank 1, or both or bank 2)  Anything I need to know?  Is it as simple as just swapping them out, like for like?  The manufacture is Trojan.  thanks.  I bought the solar charger for the summer and plan on using it.

I have a 1997 Catalina 34, hull 1348.  thanks

John

[Stu Jackson]

Yes, it's just a straight swap, be careful to keep track of the wire lugs and suggest you cover them with tape while disconnected to avoid dropping them on a battery post - could also use to identify.  Maybe make a sketch or take some digital pictures to assure conformity.

How old are they?  What makes you think they're not holding a charge? What charger do you have?

[Sailing Steve]

Most people seem to go with Trojan T-105 or US Battery US 2200, but if you want more electrical capacity, the Trojan T-125 and US Battery US 125 will fit nicely in the same compartment as the smaller two brands/sizes.  I just installed four new US 125 complete with 100 A and 40 A circuit breakers, along with two termination posts all in the same compartment.  I'm in the final throws of installing the dedicated starter battery.

The only caveat if you choose to use all four house batteries at the same time, is to have an alternator powerful enough to supply sufficient current to charge them in a reasonable time.  A constantly under charged battery suffers as much damage as a constantly over charged battery according to the literature that I've read.  If you haven't already, you may wish to give some serious consideration to a "smart" alternator regulator such as those from Xantrex or Balmar.

[Kyle Ewing]

Does anyone equalize their batteries?  See section 3-7 in the Truecharge 20/40 charger documentation (http://www.xantrex.com/web/id/462/docserve.asp).  From what I've read it increases the life of batteries.  What is your practical experience?

[Stu Jackson]

Kyle, I did a search on equalize, see reply #4 at: http://c34.org/bbs/index.php?topic=468.msg1721;topicseen#msg1721

Practical experience - yes, I've done mine with our new alternator regulator.  I cannot do it with my Freedom 15 inverter/charger because I haven't yet installed my Link 2000 and its control panel for the charger.

Recommendations as noted in my reference indicate that it's the use the batteries get that require equalization, and since most people keep their boats plugged in all the time, there seems to be little use for it.  For those who are away from SP all the time, it seems an essential part of battery maintenance.  It is, after all, the fourth stage of the three stage charging regimen!    FWIW, I think you're about only the third person who's ever asked this question.

[wind dancer]

Another Trojan golf cart battery option is the T-605.  It runs about $10 a piece cheaper, and is about 4lbs lighter.  Only 420 amps per bank instead of 240, but that's fine with me as I'm pushing it with an 80 amp Balmar alternator and 20 amp TruCharge+.

[Stu Jackson]

John, I've reread your post.  You wrote: "They are wired two (2) together and two(2) together, or I can switch them all on.( bank 1, or both or bank 2)  Anything I need to know?"

1.  They are wired 2 together and 2 together because they are 6 volt batteries.  You need 2 in series to make 12 volts.

2.  It appears that they are two different 12 V banks, but ONLY you can tell us that.  I am guessing that one bank goes to the 1 position on the 1-2-B switch and the other to the 2 position.

3.  You use the B position of the switch to combine them into one big bank.

If you are unsure about the wiring, before you do anything, trace the wires out on your boat, so you understand what's going on.

Also, given the question, I recommend that your purchase Nigel Calder's Boatowner's Manual for Mechanical and Electrical systems book, the best $50 you'll ever spend on your boat.  You could save some book $ and get don Casey's book, but why not get one that covers everything about your boat?