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Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

moving battery and extended cables

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acierno
1st Mate

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USA
62 Posts

Initially Posted - 04/05/2002 : 08:33:56

in order to achieve greater balance on my 250wk, i have been instructed to move weight forward. i want to move the batteries forward, but would like to know if there are any other modifications that would be required to address increased electrical resistance due to extra long cables--that is, what is involved in moving the batteries forward other than getting longer cables?

ron

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cathluk
Admiral

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USA
513 Posts

Response Posted - 04/05/2002 : 09:42:21

I'm sure someone with more electrical knowledge will reply, but I do know that its not as simple as longer wires - if you go longer you need to upgrade to larger gage wires. (Now would be a good time for someone with better knowledge to jump in and let us know how to figure out what gage wire is required).

Cathy
"Blown Away"
'97 C250WK #253

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mday
Navigator

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197 Posts

Response Posted - 04/05/2002 : 17:15:46

Ron,

The authority for this would be ABYC. You could order a wiring handbook from www.abycinc.org if you want all the details for future reference. It's around $30.

A general table is below from an old ABYC statndard. Basically, you have to estimate what your maximum current draw is going to be and how many feet away the load is.

Recommended wire guage for 12V systems

Current Length of wire in feet:
in Amps 10 or less 15 20 30 40 50
-----------------------------------------
5 14 12 10 10 8 6
10 10 10 8 6 6 4
15 10 8 6 6 4 2
20 8 6 6 4 2 2
25 6 6 4 2 2 1

On my C250, I have the batteries in the rear going to a distribution panel that's about midships. I'd think moving the batteries anywhere else in the boat, even up to the bow, wouldn't increase the length of the wiring and you could use the same guage wire. The biggest load I have would be for electric start on my outboard, which is close to the batteries now. If you have this setup, you'd probably want to leave a battery in the stern for the motor. I don't know offhand what the wire size is running to the outboard, but it was heftier than the wire used for onboard 12V devices.

Hope this helps some ....

Max

Max Day
C250 WB 380
Lake Pleasant, AZ

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dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 04/05/2002 : 18:46:24

Ron,

This link from Sailnet is an article concerning electrical wiring and in the middle of the article is a "Wire Size Selection Table" that may be of some help.

http://www.sailnet.com/collections/articles/index.cfm?articleid=caseyd032

Don Lucier, Northstar
C25 SR/FK

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Bryan Beamer
Master Marine Consultant

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USA
1038 Posts

Response Posted - 04/05/2002 : 21:53:13

Ron

When we moved our batteries to the v-berth our wire lenth was 24'one way. We sized our wire to the amp draw of what the motor draws at start up. That is by far the biggest draw. Then we looked at what would be running at the time we needed to start the motor and added that amp draw to the motor amp draw. When you figure that out this is the formula you use to size the wire. 2x distance x resistance of the wire x the amp draw divided by 1000. That will give you the voltage loss to the connection point in the aft storage compartment. 3% voltage loss is the most you want to lose 12volts x 3%=.36-volts. Here is a list of wire sizes and their resistance all wire is copper coated. #4-.321, #3-.254, #2-.201, #1-.160,#1/0-.127.If these wire sizes don't work for you let me know I will give you more. Here is an example: say the motor needs 40-amps the other items you will be running at the same time equal 7-amps that totals 47-amps, your wire lenth is 24' one way #1 resistance is .160. Follow the formula above 2x24'x.160x47/1000=.36 so #1 would work for a 47-amp load at a one way distance of 24'

Hope this helps, let me know.

Bryan Beamer
Daylight Again
C250wk #495

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acierno
1st Mate

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USA
62 Posts

Response Posted - 04/08/2002 : 08:08:06

thanks for the info.
ron

ron

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jkey6
1st Mate

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71 Posts

Response Posted - 04/13/2002 : 23:10:35

How many of you have moved your batteries forward?

We have considered it but so far we have just added a few bags of sand which has helped.

Where did you run the wires? In the bilge?

Thanks,

JKEY, All Keyed Up, C250WK

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Bryan Beamer
Master Marine Consultant

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USA
1038 Posts

Response Posted - 04/18/2002 : 00:18:16

I moved the two batteries to the v-berth the second weekend I had the boat in the water. I made two flat platforms in the v-berth locker and out of plywood glassed them in place. Ran the wire down the starboard seat locker to under the galley sink ( the floor around the trash can comes out)fished them to the bildge in the main floor then to the small storage in the aft berth.Then we ran them to the closet behind the head down the open aft storage area on the port side to the area behind the aft sleeping area reconnected the wires and strapped the batteries down in their new location. You will have to drill holes in the closet floor, in the small aft storage under the cushions and under the sink. The pulling of the wires and hooking everything back up took about 6 hours. Of course that is on sailors standard time. Nothing gets done fast at the relaxing marina.

Bryan Beamer
Daylight Again
C250wk #495

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jkey6
1st Mate

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71 Posts

Response Posted - 04/19/2002 : 00:08:30

Thanks,

This is on my list for the summer. If my 2 batteries weigh 100 pounds; moving them from the rear to the front is like leaving them in the rear and adding 200 poundsin the front!

Thanks for the routing.

JKEY

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Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 04/19/2002 : 08:52:27

Besides the weight transfer, Batteries in the V berth are much easier to maintain water levels. But, they can also get shaken around more...making it important to secure them well.

I used a piece of 1/2"x2'x4' plywood for the base cutting arcs to fit hull sides on the ends. I then built a box from 3/4" ply to fit the dimensions of two batteries with a bulk head between them.

The box was glued and screwed together and then to the base and the inside of the boxes sealed with several coats of spray polyurathane. A 1/2" plywood lid sits within the box sides and rest on top of the battery terminals with a hole in the center for a loop of line to extend thru it and a hole thru the center bulkhead. A length of dowel just longer than the width of the box is twisted in the loop pulling the lid secure.

I wanted to use construction adhesive to bed the plywood into the locker but thought better of it when I relized that the box would have to come out to access the two 9 gal Todd water tanks just aft of the batteries. Carpet pad was chosen instead to deal with any iregularities in the fiberglass top of the ballast tank. The plywood base is secured from moving by wood strips bonded to the tank top with PL400 construction adhesive.

It was built outside the boat, and will just fit down into the locker... this of course should be checked. Mine contains two 6 volt golf cart batteries. These are relatively tall batteries weighing 70lbs each. The height in the locker turned out to be just adequate.

Arlyn C-250 W/B #224

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jkey6
1st Mate

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71 Posts

Response Posted - 04/21/2002 : 23:01:52

Arlyn,

What gauge wire did you use?

Thanks,

JKEY

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Bryan Beamer
Master Marine Consultant

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USA
1038 Posts

Response Posted - 04/21/2002 : 23:38:24

JKEY,

The wire size is going to be different for everybody.To see how to size the wire look at the fifth reply from the top in this topic.

Bryan Beamer
Daylight Again
C250wk #495

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Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 04/22/2002 : 12:21:30

I used #6 between the two forward 6 volt golf carts and the battery switch that is on the aft berth bulkhead. It would likely be inadequate if I were using it to start the motor. The motor is wired to a single group 24 battery remaining in the normal box. I went this way... because I had the #6.

Arlyn C-250 W/B #224

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