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Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

One Battery or Two

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Bruce Baker
Captain

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USA
402 Posts

Initially Posted - 02/23/2003 : 10:54:45

I've just bought a CD player for my boat, and I'm thinking of adding a second battery. I'm wondering if this is necessary and desirable? How many C-25's have made this conversion?

Thanks,
Bruce Baker
"Yee Ha"
Falls Church, VA

Edited by - on

ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 02/23/2003 : 11:50:06

The necessity part of deciding on one or two batteries depends on your total amperage consumption and how long you need to go between chargings.

In it's simplest form, (no mid-trip recharging) you determine your electrical budget by multiplying the current draw of each electrical device (amps) times the number of hours it is expected to be used each day (hours) times the number of days you need to go between battery charges.

Example...

Cabin Lights 10 amps X 5 hours/day = 50 amp/hours/day
Anchor Light 5 amps X 10 hours/day = 50 amp/hours/day
Nav Lights 10 amps X 5 hours/day = 50 amp/hours/day
GPS 2 amps X 10 hours/day = 20 amp/hours/day
Depth 5 amps x 24 hours/day = 120 amp/hours/day
CD Player 10 amps x 5 hours/day = 50 amp/hours/day

Total daily usage... 340 amp/hours

So if your longest anticpated trip is 5 days, you will consume
1700 amp/hours. Divide this into 60% or so of your rated battery capacity. If demand exceeds supply, you need to add battery capacity.

Adding a second battery is relatively easy... and usually adds resale value to a boat. You need a mount, fusible link, and an A-B battery switch. Likely lots of articles on doing this out on the web already.

Currently maintaining two holes in the water...'77 Venture 23 and new to the family,
'78 Catalina 25

Edited by - on

Ken Cave
Navigator

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USA
148 Posts

Response Posted - 02/23/2003 : 13:31:22

It also depends on what size and type of battery you plan to use.

A typical wet cell will get harder and harder to charge to full capacity as it ages, unless you have one of those high amp chargers that can really zap it.

On my Catalina, I installed a series 24 gel battery as they are easier to charge and can take a lot of abuse without failing.

I did not have an electric start on my outboard, but I did have an Autohelm, GPS, radio, and lights (be careful on how you use the lights if they are the original.) and could sail for a week without a charge.

If you can get to a dock with electricity in a weeks time, one battery should be enough, as a CD player takes literally nothing to run them. I have a portable player hooked up to the radio in my present boat that I run on batteries. Have had the player for about six months and have yet to change the batteries!

Hope this helps

Ken Cave

Edited by - on

tinob
Master Marine Consultant

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USA
1883 Posts

Response Posted - 02/23/2003 : 16:29:21

HI KEN GOOD TO HEAR FROM YOU...VAL

Val Bisagni]<img src="http://im1.shutterfly.com/procserv/47b3df11b3127cce94709c5ff2e90000000010" border=0>

Edited by - on

jsummerfield
1st Mate

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USA
96 Posts

Response Posted - 02/23/2003 : 19:27:34

I have a battery switch and two batteries. I thought that this was original equipment. I have an electrical start on my outboard and a VHF. I recommend two batteries.

Edited by - on

Leon Sisson
Master Marine Consultant

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USA
1893 Posts

Response Posted - 02/23/2003 : 23:12:47

Bruce,

If you have electric start (especially if there's no rope start backup), then I'd say it makes sense to have two battery banks. I have a dedicated cranking battery (group 24), and a house bank consisting of two group 27s. Another alternative for the house bank is an even number of 6V golf cart batteries.

As 'ClamBeach' said, it's a good idea to start by calulating your electricity budget, and go from there.

I suggest that anyone who has, or is considering, multiple batteries should look into battery combiners. Also, the traditional [OFF/1/BOTH/2] battery selector switches seem to be out of vogue these days. I think the latest recommendation is separate high current [ON/OFF] switches for each bank. A good combiner can be used for paralleling if needed in an emergency (such as house bank too drained to make one more batch of margaritas in the 12V blender and still run the stereo).

-- Leon Sisson

Edited by - on

Bruce Baker
Captain

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USA
402 Posts

Response Posted - 02/24/2003 : 10:13:44

Leon,

Thanks for your input. However, I'm unlikely to encounter the type of "emergency" you describe. I've upgraded my 12V blender to one that can really crack some ice. Check this out:

http://gasblender.com/detailed.htm

Bruce

Edited by - on

Kirk McKay
Navigator

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USA
111 Posts

Response Posted - 02/24/2003 : 14:35:01

Ok, can you keep this thread going and let's hear what type of batteries everybody uses? I am now 100% sure my old wet cell battery is toast and will be purchasing a new one shortly. We will never be out more than a night or two, have electric start on the OB (with rope b/up)and don't use many electrical toys other than CD, VHF, depth and the minimum lights. Should we spend the bucks for a gel or stick with the wet cell?

Kirk

Edited by - on

Champipple
Master Marine Consultant

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USA
6855 Posts

Response Posted - 02/24/2003 : 15:22:11

While we are on the topic of electricity and batteries, does this diagram work (if one of you electrical engineering types could look at it I would appreciate it)
<img src="http://im1.shutterfly.com/procserv/47b3dc05b3127cce94988a3a0da00000001610" border=0>

What you can't see on this drawing - line connecting negatives on batteries...

DW

D. Wolff - "The Flying Wasp" #401 sr/sk
Chief Measurer C-25/250 National Assn.
<img src="http://www.flags.com/dreamimages/Flags/measurer.jpg" border=0>

Edited by - on

Bruce Baker
Captain

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USA
402 Posts

Response Posted - 02/25/2003 : 09:09:56

Duane,

I can't comment on the schematic based on my own knowledge, but you might want to check out the 12 Volt Bible for Boats by Miner Brotherton (available on Amazon). I got a coupon on the mail from West Marine last week (worth $10 off anything in the store) and I invested mine in the 12V Bible. I need to convert the three-wire system for my old mast to the new four-wire system on my new mast. Looking at the battery schematics in the book got me going on this topic in the first place.

Cheers,
Bruce

Edited by - on

Buzz Maring
Master Marine Consultant

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USA
1772 Posts

Response Posted - 02/25/2003 : 10:24:44

<font color=blue>I need to convert the three-wire system for my old mast to the new four-wire system on my new mast. Looking at the battery schematics in the book got me going on this topic in the first place.

Cheers,
Bruce
</font id=blue>

Hi Bruce,

I need to do the same thing. When you "crack the code," would you please post it on the Forum?

Thanks!

Buzz Maring, C-25 SK/SR #68, "Freya"
<img src="http://im1.shutterfly.com/procserv/47b3df23b3127cce9306a9b3abad0000001010" border=0>

Edited by - on

Stu Jackson C34
Admiral

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844 Posts

Response Posted - 02/25/2003 : 13:03:47

Duane's Sketch

Duane, it looks OK as drawn, and will work. However, why bother with the battery isolators? They take about a volt right out of your charging system. The simplest thing to do is to run the red wires from the charger to the 1-2-Both switch and use the switch as the method to choose which battery or both to charge. As long as the charger's on long enough to top off the batteries, you won't have one draining into the other without getting them both up to snuff. An alternate choice would be a battery combiner with the charger going to the house bank. However, I don't know if you're using one battery as a satrt bank and the other as a house. Just diss the isolators, they're ancient and not very helpful in charging, and will almost assure that you are chronically undercharging your batteries, which isn't very good for them. Any further questions, let me know.

Stu

Edited by - on

John Mason
Admiral

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USA
687 Posts

Response Posted - 02/25/2003 : 14:25:12

The four wires up the mast are Green-Ground, White-Bow light, Orange-Anchor light, Yellow-Deck light.

Here's the link to the schematic - http://c25c250.best.vwh.net/restricted/4-2-4.gif

John Mason
<img src="http://www.users.qwest.net/~jamason/ali.jpg" border=0>
pronounced "Ali Paroosa"
1982 - FK/SR #3290

Edited by - on

Carl B.
1st Mate

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USA
83 Posts

Response Posted - 02/25/2003 : 22:57:47

Has any one had any luck pulling new wires thru the deck were the old wires ran? If so what is the trick?

"OBLIVIOUS" C25 '82 #3098 SR/FK/Trad

Edited by - on

John Mason
Admiral

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USA
687 Posts

Response Posted - 02/26/2003 : 11:54:12

When I rewired my mast, I had to run the wires along the top of the bulkhead in the head area. Just drilled a hole angled forward down through the original deck plug "platform" on the deck. The original wires are sandwiched in between the bulkhead and the cabin top. Unless you want to remove the chain plate, bulkhead, etc., they're inaccessible.

On my boat, the old wires wouldn't budge, so I couldn't feed new wires through that way.

John Mason
<img src="http://www.users.qwest.net/~jamason/ali.jpg" border=0>
pronounced "Ali Paroosa"
1982 - FK/SR #3290

Edited by - John Mason on 02/26/2003 11:56:12

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