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Current Replies for Adding a second battery
  Adding a second battery (bedlaminthewater)
Posted: 10:32:04 am on 8/20/2016 Modified: Never
Hi Guys
Im adding a second battery to a 1972 MK1. Im looking for help and suggestions (and pictures) from anyone whos added a second battery to an early C&C 27.

Marc Purcell
C&C 27 MKI
Port Whitby Marina
Whitby, Ontario

  Re: Adding a second battery (doogymon)
Posted: 11:35:31 am on 8/21/2016 Modified: Never
Hi Marc

My C&C 27 has her batteries to port, strapped side by side to a shelf with access from the port cockpit locker. They are located tight up against the lower half bulkhead that separates the engine room (and tiller flats)from the cabin. The big red battery switch is mounted on the same bulkhead close to the batteries with the face of the switch appearing on the cabin side of the bulkhead.
Some boats may have their batteries mounted more forward, on the sole of the boat, beside the engine, with access through the cabin engine room panel behind the companionway ladder.

Not sure which is optimal (for racing!).


  Re: Adding a second battery (bedlaminthewater)
Posted: 8:26:09 pm on 8/22/2016 Modified: Never
Thanks for the response.

My boat has a single battery under the ladder beside the engine. I think this is the traditional location. Im adding a second battery. I was considering building a shelf and stacking the batteries one above the other. Im not sure if this is the best option.  

Marc Purcell
C&C 27 MKI
Port Whitby Marina
Whitby, Ontario

  Re: Adding a second battery (KenPole)
Posted: 12:44:18 pm on 8/23/2016 Modified: Never
For what it's worth, working from the premise that having batteries right beside an engine is not a good idea because of heat and vibration, I opted to run appropriately-gauged cable through the space behind my icebox and into the storage area under the portside aft seat. Power is routed through a 1-2-all switch mounted on a panel I installed behind my icebox. The batteries are mounted as close to the centreline as possible. However, I use two Odyssey AGM batteries, one for starter for my Atomic 4 and the other as a house battery. These are smaller than conventional lead-acid batteries but are more than up to my needs in that the A-4, with a displacement of one litre is easy to start, and all my lights, as part of a stem-to-stern rewiring, are LEDs. I use the former battery area to house a waste bin and provide other storage, separated from the engine by a plywood bulkhead.

Ken Pole, Ottawa
1975 Mark III Santiva

  Re: Adding a second battery (bedlaminthewater)
Posted: 9:57:05 pm on 8/25/2016 Modified: Never
Thanks Ken. I was concerned about placing two batteries beside the engine. I found an image of that configuration but I like your suggestion better.  
  Re: Adding a second battery (wjames)
Posted: 3:52:01 pm on 8/29/2016 Modified: Never
Almost from the very beginning when I bought Sesiya new in 1976, I have used two batteries, one for "engine" and one for "ship's power". I am no expert, but the batteries are strapped in securely one above the other on a wooden shelf (mostly teak) alongside the engine forward of the bulkhead and behind the plywood cover, on the port side near the icebox. Heat and vibration have never been an problem. The main switch is on the bulkhead at the top of the companionway steps. A 110v charger, a solar panel and a voltmeter are wired in via a custom 12V switch panel which is built in above the icebox, together with the VHF, GPS-plotter, inhverter and power outlets.  Of course all this stuff has been replaced once or twice over the intervening 40 years - lighting is now LED. I have cruised singlehanded in all lakes but mostly Georgian Bay over all this time, including some very rough weather situations, with one cruise to Quebec City, and with this arrangement power management has never been a problem.

How does one attach photographs here?
  Re: Adding a second battery (admin)
Posted: 9:57:27 pm on 8/29/2016 Modified: Never
<How does one attach photographs here?>

You don't. You can either read the bit about "Using photos in your posts" in <> or send them to the admin and hope that he finds them sufficiently entrancing to do something with them.

Off the cuff, I'd say that a photo of two batteries abaft the aft end of the engine, or one battery in front of the after accommodation bulkhead and one behind, or two batteries one on top of the other in the forward end of the engine compartment are comprehensively descriptive.

- Admin

  Re: Adding a second battery (bedlaminthewater)
Posted: 8:34:36 pm on 8/30/2016 Modified: Never
Hi Bill

Thank you very much. If I send you my personal email address would it be possible to send a picture?

Thanks again

  Re: Adding a second battery (admin)
Posted: 10:39:04 pm on 8/30/2016 Modified: Never
"Using the Forum (from

We want the Forum to be a durable resource, which is to say that if you have an interesting question and someone out there has a thoughtful answer, we want them on the site so that others can read it, today and for as long as this site lasts. Therefore, Rule Number One (the one and only rule on the Forum) is:

You will not ask people to send answers to your e-mail address or phone number. That's no use to the other people who use and contribute to the site, and who might someday have need of that information, so we want the question and the answer in the Forum. Therefore e-mail addresses and numbers will be promptly deleted. The only time they are acceptable is when you're trying to buy or sell a boat or gear."

That said, if people want to send me photos of battery layouts, I will look at them and if they elucidate real problems, I will add them to Black Arts.

- Admin

  Re: Adding a second battery (wjames)
Posted: 9:39:06 pm on 8/31/2016 Modified: Never
Yes of course I will share photos with the Forum (and personally) as soon as I can take them (Sesiya is berthed at Sound Boat Works - search the web - in Parry Sound and I live in Guelph, so cannot photograph for another couple of weeks). Meantime I can add that both batteries are clamped in place using Attwood battery hold-down trays (search the web), which have served me excellently for 3 decades. (Sesiya has been flattened to mast horizontal some 3 times in that time, and has too often been shaken up by 3-4 ft waves, and the batteries have never moved!) The shelf for the upper battery is 5/8 inch marine play fixed at the back to the bulkhead with a brass piano hinge (to facilitate removal of lower battery, if problematic, which it never is). The front edge of the shelf is fixed to two solid teak legs that are fixed to the original lower shelf so that wiring is accessible and all is well ventilated. By the way I find that my boat bounces around much less at the stern than forward, so perhaps aft is indicated for batteries.

Readers may be also interested in the related wiring that renders dual battery power management convenient and effective, and something to think about from the outset.

Real-life inspections also welcome - though Parry Sound is a long way from Whitby.

-William James, Guelph