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Avoiding a marine battery?


Kyle H.

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Hi All ~ I have not posted to this main forum yet, so hello to all. :D

I am building a Belhaven 19 and am wondering if I can get by without a marine battery. I will use a Torqeedo electric engine for auxillary power, and plan to purchase running lights and a masthead light that are removable and disposable cell battery operated. Interior boat lights will also be LED dsiposable battery operated.

Now, what ideas do you have for me to power a depth sounder and also to light a compass at night?

I can't offhand think of any other electronics I might need, but please do chime in if I have forgotten something essential.

Thanks for your help and ideas!

Kyle #44

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Now, what ideas do you have for me to power a depth sounder and also to light a compass at night?

Hi Kyle,

Some folks use one of the little portable/self-contained jump-start battery packs that are usually carried to jump-start a car or to power electronic devices at a campsite. I preferred to build my own for weight and bulk reasons so it would be custom-fit to my hatch compartment. You can see the power station I built at this link: http://www.roguepaddler.com/cs20u.htm (look under "12V Power Station").

I would think the Torqueedo would require you to have quite a large battery, but if you only need one for the depth sounder and compass, you should be fine with a smallish battery like the one I'm using: a Werker 12V 18Ah AGM battery, which happens to be the same size used in many of the jump-start packs sold commercially.

Wes

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I preferred to build my own for weight and bulk reasons so it would be custom-fit to my hatch compartment. You can see the power station I built at this link: http://www.roguepaddler.com/cs20u.htm (look under "12V Power Station").

Looks really good, Wes. Would this unit be solar compatible for recharging?

I would think the Torqueedo would require you to have quite a large battery...

The Torqeedo I have has a nine pound battery that sits atop the engine itself. I recharge it by house current each time after use. There is a folding solar panel option for recharging that Torqeedo sells, but it is $900.00.

Much thanks for your ideas!

Kyle

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Might I recommend an energy free depthsounder then?

Hamilton Marine sells the Nantucket Sounder. Bronze weight with a hollow end that you can fill with tallow attached to a long rope. You toss it over board and then retrieve it after it hits bottom. Every arm length of rope hauled back aboard is close to a fathom. The tallow on the ends of the sounder allows you to sample the bottom to see what it is made of.

Worked for mankind for thousands of years too.

When I sail in my 19 foot West Wight Potter (very similar to Bellhaven in many respects, (Bellhaven will be a much better sailor though) I have Battery Operated Nav Lights and Anchor light. I have LED lights to arrange around cabin amd I use a jumpstart battery to recharge cell phone and run GPS and power inverter to shave with electric shaver.

Course I use a gas motor as axillary rather than electric motor.

Despite being ABYC certified Marine electrician I am a minimalist regarding electricity aboard boats. I would be very happy to go with Kerosene light as well. But My wife won't hear of it.

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Looks really good, Wes. Would this unit be solar compatible for recharging?

Yes, it could easily be arranged that way. You would need a small charge controller to regulate the power from the panel. To the best of my knowledge, Morningstar still makes the smallest/cheapest (of good quality) for that purpose. Then you would combine it with a panel that does not exceed the maximum capacity of the charge controller.

My Lowrance GPS/Sonar combo unit draws only 0.9A, so with an 18Ah battery, I could run the unit approximately 14 hours (2 full days of continuous 7-hour operation) before I'd drain it down to the max recommended depth of discharge (80%). I don't run my unit anywhere near that much, so I have plenty of reserve capacity with this little battery (only about 13 lbs and a small footprint) to do a weekend camp trip without recharging. If I were going to rig a solar panel, I'd consider going even smaller on the battery to save weight/bulk... maybe 10Ah. Wouldn't take much of a solar panel to stay on top of such modest energy needs.

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Thanks Ray. I guess I tend towards the minimalist route, too, although that wouldn't hold true to my many boat habit...sigh. :rolleyes:

The Sounder might be just the thing. I have two sheep, so tallow is available, but that would mean they would have to go on the chopping block...Homer and Jethro have been with me too many years for that!

I remember many nights at anchor with kerosene lanterns...a little smelly sometimes, but very romantic! ;) I will definitely go the LED route as much as I can.

Thanks for your valuable input.

Kyle

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I'm guessing your electronics and nav lights draw very little, so its the motor you need to buy the battery for. My understanding is that the main difference between a car battery and a deep cycle battery is this. The car battery must deliver a lot of amperage to turn the motor, but only for a short time, so it's made with lead plates that are spongy to expose maximum surface area. It is not safe to discharge such a battery very deeply, since that will kill the battery very quickly. A deep-cycle battery uses solid lead plates, which cannot deliver as much amperage as a car battery, but can deliver its energy over a longer period because it can be discharged to a greater extent (say, to 50%) without unduly shortening the life of the battery. So yes, it seems to me you can't easily avoid buying a couple of these. (I usually carry two for my trolling motor, since it's not a good idea to be without a motor you were counting on at a critical moment.) I hope someday to be able to afford a gas outboard, which has fewer limitations.

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The "plan" that I have is to use a pair of 6 volt lantern batteries wired together for 12 volts to power the nav lights etc. I have this in place with the batteries mounted in a small box in the forepeak and it works quite well for me and was dead cheap.

For potential future electric motor I've run 6 gauge wire from the forepeak to the transom (reclaimed battery booster cable). I'll put an appropriate battery in the forepeak for this and use a relay kept in the transom that I'll activate using the smaller batteries and a switch to turn it on and off. I still have to save up the money for the motor yet and in the mean-time I use oars and hope for a calm day or the wind to blow in the right direction.

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The "plan" that I have is to use a pair of 6 volt lantern batteries wired together for 12 volts to power the nav lights etc. I have this in place with the batteries mounted in a small box in the forepeak and it works quite well for me and was dead cheap.

Considering the actual times per year and hours that you will likely use your running lights this would seem a most viable option. I will have to remember this when I build my future day sailor.

For potential future electric motor I've run 6 gauge wire from the forepeak to the transom (reclaimed battery booster cable).

I am sure Ray will chime in with some comments here but a couple thoughts on this:

1. Marine cable is tinned stranding to resist corrosion. I would bet your booster cable is not.

2. Marine cable uses much smaller stranding than most wires to resist hardening due to vibrations and thus resist shorts and breaks.

3. Have you sized the wire required by a typical electric outboard based on the amperage drawn and the voltage drop over the length of wire?

I think planning ahead on how to get the wire run is a great idea. Maybe running a line to use later to draw the wire through is a better idea?

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Considering the actual times per year and hours that you will likely use your running lights this would seem a most viable option. I will have to remember this when I build my future day sailor.

I am sure Ray will chime in with some comments here but a couple thoughts on this:

Reclaimed Booster cable wire sure wouldn't be my choice.

All good points you make on why too.

Number on cause of boat fires is electrical problems. 12 Volt battery can burn your boat nicely.

Do it right or keep the oars...

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I think planning ahead on how to get the wire run is a great idea. Maybe running a line to use later to draw the wire through is a better idea?

On our CS20, during the build I ran a 1" diameter PVC tube from the forward to the stern locker, with "T" fittings inside each seat compartment along the way. This was so that we could install permanent wiring later if we decided to go with permanent lights. We currently use suction-cup self-contained battery lights that work fine for our needs since we are almost never out past dusk. But it might be a good solution if you think you may want to add wiring later. Our PVC is capped at all of the ends and "T" intersection access points, and sealed at each place it passes through a bulkhead, so it doesn't undermine the watertight integrity of each sealed area.

Just another possibility.

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