Electric Trolling Motors and Battery.

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Re: Electric Trolling Motors and Battery.

Postby GreenLake » Tue Jun 27, 2017 7:55 pm

That is a very nice sailing area.

I opted for not installing wires permanently, but I agree that this would not be the best solution in your case.

First, the best location for your battery (preferably plural, as in two) would be as near the mast as you can manage. Otherwise the balance of your boat will be adversely affected. The downside of that is that you'll need a pretty long run of cables. To avoid unacceptable voltage drop you'll need to use wires that are substantially thicker than what came with the motor. (The label on the cable says AWG 4).

What I did, is to borrow a professionally sized crimping tool from the shop where I bought the wires and used that to crimp eyes on either end of the "extension" cable. I couldn't find any fittings that connected cables of different sizes, so I used a small block connector with four screw terminals to connect the original wire with the "extension" cable. (Each has eyes, so I just screwed the eyes onto matching posts on the block connector).

The connector has holes where it could be screwed to the hull (or better, to a piece of marine plywood bonded to the hull with epoxy - and also sealed with a coat of epoxy). My idea was to fit that underneath the gunwales in a DS1. For a DS2 you could do that under the seat, with an inspection port.

To connect the motor, I purchased (but never used) a trolling motor socket. My idea was to cut the original leads from the motor and attach each end to plug/socket to make the motor removable. I think you should be able to do that with the socket mounted in the seat. I wanted to cut the motor leads because the connector did not support the heavier gauge of my "extension" and the socket would be located closer to the motor anyway. (The connector I have would have been connected by stripping about 1/2" off the end of the cables and inserting them into holes where they can be clamped with screws on the connector. For this kind of connection do not solder the ends but use dielectric grease to keep out moisture).

You may want to get some kind of additional enclosure for the block connector, just to keep salt and moist air out. A simple plastic box that you can tape shut (the main protection would be from being under the seat). Also put some dielectric grease on the eyes and screws to cut down on corrosion.

To connect the circuit breaker you'd have to look at how it is designed. Does it have screws for eyes? If so, cut your cable a the appropriate place and crimp eyes onto the end. If it is inline, just place it where it won't get wet, if it bolts to the hull, treat it the same as the connector box in my setup.

On the forward end, just have the cable exit the seat and seal that exit with something. Leave enough loose cable to connect to a battery (and if you have two, to reach either one).

Anyway, other than not having mounted the plug/socket or having bolted the connector block to the hull, your planned setup matches what I've been using. So I hope this description gives you an idea how to proceed.
~ green ~ lake ~ ~
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Re: Electric Trolling Motors and Battery.

Postby talbot » Wed Jun 28, 2017 1:39 am

I think Cabela's has a simple diagram on their Web site for connecting a breaker. It goes on the positive cable, as close to the battery as you can mount it. My battery box is in the cuddy floor, so my breaker is on the mast support. That means I had to run cables aft to reach the motor. Obviously, the wiring is much simpler if the battery is in the stern. Bad place for the weight, but simpler and lighter.
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Re: Electric Trolling Motors and Battery.

Postby Patriciasailing » Wed Jun 28, 2017 11:37 am

Thank you for your information. I went searching yesterday for the battery. Minn Kota recommends a 105 AH deep cycle lead battery, but I want maintenance free and safer battery. The AGM 105 AH is very big and heavy I think for such a light sailboat. Someone at West Marine said I would do more than OK with a 77 AH AGM battery for the trolling motor. I looked for batteries at SAMS. Much better price but they only had the 55 or 105 AH batteries. Not the 77 AH one. What do you think, should I get the big and heavy 105 or the 77 AH?
Also, how do you move the wires inside the seat from the stern up to the cuddy? And where should I place the additional inspection port, Next to the plug or midway to the cuddy? And should I forego installing a plug at the stern and just crimp the motor cables on the extension conduit for it to reach the battery in the cuddy?
Does anyone have pictures of the wiring inside or outside the seats? Thanks again for all your help!
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Re: Electric Trolling Motors and Battery.

Postby TIM WEBB » Wed Jun 28, 2017 1:24 pm

Minn Kota sells a battery box with the circuit breaker(s) built in. That's what I used, and the wiring in the cuddy looked like this:

1005

1004
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
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Re: Electric Trolling Motors and Battery.

Postby talbot » Wed Jun 28, 2017 2:34 pm

My setup looks more or less like Tim's. I had previously added an inspection port in the seat back to help with the reinforcement of oarlocks, so I used that to reach in and pull the cables. It ended up being more complicated than I expected. I wanted to keep the tanks watertight, so I used sealing bulkhead through-hulls for the cables. To get them to seal tight, I ended up putting a port inside the cuddy to access the end of the tank. That let me get in to tighten the back side of the through-hull. Then I wanted a motor plug in the seat back close enough to the motor so that the cables would be out of the way in cockpit. I ended up putting a small (4") port way aft in the seat back, just to make it easier to hook up the plug. Turned out to be useful when a plug connection came loose while I was out on the water. Relatively easy to reach in, reconnect, and tape the loose cable in place. To the extent possible, support your cable aft every 18" with cable clips (you can glue the fasteners to the inside of the . That may not be possible, but that would let your boat meet standard specs.
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Re: Electric Trolling Motors and Battery.

Postby Patriciasailing » Wed Jun 28, 2017 3:14 pm

Thanks Talbot. When you say you put a porthole on the seat back, do you mean where your leg calf would touch the seat or your back? and the porthole to the cuddy, was it on the cuddy wall facing the bottom of the seat or facing the cockpit?
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Re: Electric Trolling Motors and Battery.

Postby Patriciasailing » Wed Jun 28, 2017 3:18 pm

Thanks Tim Webb. Wish I had known of the Minn Kota battery box. I purchased the motor through craigslist, but I did go the Minn Kota´s webpage but did´t see it. Still trying to digest everything. Size, type of battery? one or two?
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Re: Electric Trolling Motors and Battery.

Postby GreenLake » Wed Jun 28, 2017 4:18 pm

You need a marine or deep cycle battery, not a starter battery for a car.

You can discharge a deep-cycle battery to about 50% of its total charge without destroying it; they are designed for that. In contrast a starter battery normally gets recharged immediately and most discharges are therefore "shallow". (Deep cycle batteries will also have the screw type terminals that you need to attach your cables, not the lead-posts you may be familiar with from your car battery).

Two batteries. For one, splitting things across two batteries gives you a bit of added safety in case one of the batteries decides to fold on you. For the same reason, you should normally plan things so that one battery should get you home, or if not home, then to some alternate safe location.

Size: 80-100 amp hours each. Larger than that, the individual batteries get too heavy to handle (and ultimately, too heavy to have around on your boat) and smaller than that, your range is going to be too short -- unless you strictly use it to get in/out a marina or on/off a beach).

Each of my batteries gives me a about 40 min on full thrust (40#) with a top speed around 2.5 knots. So I can cover about 1.5 nm with each. The next lower setting gives me 1.8 kt, but at about half the current, so I can go about twice as far on each battery (as long as there's no wind or current to fight).

I make an annual trip across one of the lakes where on the return leg the wind wind usually dies (or is blanketed) for up to half the distance. So I end up motoring something between 1 and 2 nm in a dead calm, and some years I need both batteries and some years I don't. (Your mileage may vary).
~ green ~ lake ~ ~
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Re: Electric Trolling Motors and Battery.

Postby Patriciasailing » Thu Jun 29, 2017 12:31 pm

Thanks for the advise GreenLake. I will then plan for two AGM 105AH batteries. AGM, Gel (expensive) or lead (unsafe?)?
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Re: Electric Trolling Motors and Battery.

Postby talbot » Thu Jun 29, 2017 1:04 pm

For an unballasted centerboard dinghy, I think the choice is between gel and AGM because they are sealed and could potentially survive a capsize if they are strapped into the boat. I've always used AGM (less critical charging protocol), but I know others with Day Sailers who use gel (somewhat higher performance).
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Re: Electric Trolling Motors and Battery.

Postby GreenLake » Thu Jun 29, 2017 3:06 pm

I've only ever sailed with standard liquid cell batteries, but gel/AGM may make the difference in surviving a capsize. I agree they could be the better choice for sailing into more remote areas or longer cruises where being able to self-rescue becomes more important (and where conditions can't be predicted as well as for an afternoon sail in moderate conditions). Do read up on the proper charging protocols for whatever battery type you plan on using.
~ green ~ lake ~ ~
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Re: Electric Trolling Motors and Battery.

Postby TIM WEBB » Thu Jun 29, 2017 3:21 pm

Patriciasailing wrote:Thanks Tim Webb. Wish I had known of the Minn Kota battery box. I purchased the motor through craigslist, but I did go the Minn Kota´s webpage but did´t see it. Still trying to digest everything. Size, type of battery? one or two?

No prob! I got the battery box on Amazon, and the battery was an Optima Blue Top.
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
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Re: Electric Trolling Motors and Battery.

Postby talbot » Thu Jun 29, 2017 3:39 pm

FYI, Optima Blue Top is the gel battery I usually see on boats. My choice of AGM has been heavily influenced by Cabela's occasional sales, which knock the price of their AGM's way down. Another thing about strapping in: It's not optional. On the Precision TrailerSailer forum a few weeks ago, the owner of a P-185 (sort of like a DS without the cuddy) reported a capsize in which the battery box came out of the boat, pulled the Minn Kota 45# off the transom, and she lost both. The only good thing is that she was able to upgrade both the motor and the battery. And, of course, the battery hold-down.
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Re: Electric Trolling Motors and Battery.

Postby TIM WEBB » Thu Jun 29, 2017 4:04 pm

The Optima Blue Top is marketed as a "deep cycle", but not sure if that's really a "thing" with AGM batteries?

My battery box was U-bolted to and in front of the mast stub in the cuddy.
Tim Webb
1979 DS2 10099 The Red Witch
(I used to be Her "staff", in the way dogs have owners and cats have staff, but alas no longer ... <pout>)
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Re: Electric Trolling Motors and Battery.

Postby Patriciasailing » Fri Jun 30, 2017 1:24 pm

Great information and very useful to me. Thanks everyone!
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