battery cable upgrade

[jdoorly]

I decided to upgrade the battery cable to my trolling motor- I was advised a while ago by Greenlake that the voltage drop was a significant problem and could slow the motor and use up the juice too fast. I need 22 feet of cable to replace the existing 8 AWG lines (12ft for pos and 10ft for neg). I don't plan on replacing the 8 AWG distribution jumpers to the circuit breakers and selector switch, that's probably 18 inches, nor the wires from the bulkhead connecter to the motor, I think they are 10 AWG and 2 feet long.

FYI: AWG is american wire gauge and little teeny hair like wire is like #35, house wiring is #14, and increasingly bigger 12, 10, 8, 6, 4, 2, 1, 0, 1/0, 2/0, 3/0, ...

I spent some time trying to find a deal on 2 AWG wire. Most marine stores want $3.50 to $4.00 a foot and any internet deal is offset by shipping costs. I finally found good deals by searching for audio power cable, you know MONSTER cable. I found 25ft of 1/0 AWG oxygen free tinned copper wire for about $35. The 'oxygen free' and the cable make up of many tiny wires, and the choice of cool colors is probably more about audiophiletalk but it can't hurt my DC application and will reduce my voltage drop due to limited cable capacity. 3 knots here I come!

[Alan]

Wow, good timing. I was on the verge of using leftover no. 2 house wire for my second set of cables, since no.2 marine grade wire locally has jumped from $7.00 a foot to $15.00 at the local West Marine store (guess I live in an expensive neighborhood).

[Alan]

Jay,

Wish I'd followed your example and looked online in the first place. I paid $7.00 a foot at my local marine store three years ago. I've since found No. 2 marine wire at $3.25 a foot with free shipping at www.genuinedealz.com. They've also got 1/0, but for considerably more than you paid.

They've also got some really massive quick-connect plugs for heavy-gauge wire:

http://shop.genuinedealz.com/Quick%20Connect%20Plugs/

One slight caveat: They're sold and priced individually - that is, you need to buy two halves to make up one plug. They don't really make this obvious (although it's mentioned in the video on that page).

But, having received mine, I can say that they are very heavy duty, and in my opinion worth the price.

[talbot]

I've just acquired a used Minn Kota motor. Anyone on the forum willing to coach me in how to hook it up? I still need to get a deep-cycle battery. Questions:

1. Where do you put your battery?
2. How do you keep it in place while sailing?
3. I keep my boat at a dock with no easily accessible power. What do you know about solar charging?
4. Is there a way to quickly plug/unplug the motor from the battery?

I should say that over the years, my hull liner has been perforated with so many inspection ports that I could run a cable between the hulls to just about anywhere on the boat. I just don't know what to do with it when it arrives.

Thanks for any advice you can offer.

[TIM WEBB]

Just did this setup (DS2):

Deep cycle battery in a "Power Center" battery box from WalMart, with 2 cigarette lighter type sockets on the sides of the lid, and +/- posts on the front. Also a handy power meter built in. Mounted just forward of the mast, using the tie down that came with it, except I replaced the plastic buckle with a SS friction adapter. I don't really use the 2 sockets much, as it's a reach unless you crawl into the cuddy. Instead, I mounted a socket on the 1st stringer forward of the cuddy roof lip. I use this mainly for the trickle charger.

Off the +/- posts are 3 lead pairs: one goes to that socket, one goes to the stereo I mounted on the stbd seatback, and one goes back to the motor. All wires are led up from the box and zip-tied to those little square cable organizers you can get at Lowes, all mounted to the stringers w/ 1/2" SS self-tapping screws, plus the adhesive backing they have. This way all the wires go off on their merry way along the roof of the cuddy instead of cluttering up the floor ...

For the motor wire, I used the 1/0 battery cable, and Nicopressed Amp fittings on the ends. Hole-sawed openings inside the cuddy and in the seat back near the motor, and used the tent pole trick to lead them back. For the connection to the motor, I bolted the existing wires that come out of the motor (about 2' worth) to the Amp fittings on the 1/0, then repeatedly dipped each junction in Plastidip (Lowes). Then I zip tied everything together and tucked it back in the hole. Also used hole grommets to protect the edges, although I could not find grommets w/ a 2" ID, which is the size of the hole saw I have, so had to make do w/ 1-3/4" and cut a slot in them. Had no need for a plug or receptacle of any sort, since the troller is pretty much "stuck" on the transom ...

Had a chance to try it out yesterday evening, and there is a *definite* improvement in motor power. I was making about 2.5 kts into a 5 kt wind at sunset ...

I'll try to post some pix tomorrow ...

[jdoorly]

When I bought my DS2 it came with a Minn Kota Endura 36 and a battery but the previous owner abused the battery, and I didn't know anything about batteries at that time so I had a nothing but trouble with it. The Minn Kota clamped on the transom wall, the battery lived in the well next to the transom, and the motor wires attached directly to the battery with alligator clips, the red wire to the positive (+) and black wire to the negative (-) battery terminal.

The boat trimmed (down) by the stern even with no one aboard so I wanted to move some aft weight forward. Having been left with no battery power on many occasions I also wanted to add a second "get home" battery. Then I researched why batteries go bad before purchasing 2 new batteries.

The first rule of batteries is to recharge a battery immediatly after using it. The second rule is to recharge using a "smart" battery charger- i.e. recharge each battery at 5 amps until fully recharged and then automatically switch to trickle charge (full time) until the battery is put to use again. The third rule is to discontinue using the battery once its' voltage has dropped from it's normal 13.5 volts down to 12 volts, not only does it reduce battery life not to do so, but some electronics, such as my tiller pilot, will fail to function below 12 volts. The fourth rule is a reiteration of the first: Don't let the battery sit around in an uncharged state, it will reduce battery life and chargeability. And fifth is don't let the battery sit in water, the water can create an induction field and drain power.

The length of the wire between the battery and motor is important because the wire has some resistance, so the longer the wire the greater that resistance. Before I upgraded my wire size from #8 gauge to #1/0 gauge I had a 0.7 volt drop caused by the wire. 13.5 volts minus 0.7 volt drop leaves only 12.8 volts, of which I can only use 0.8 so I could only travel half as far on a charge. A fatter wire size has less voltage drop per foot. I would have used #2 gauge wire but I found the #1/0 stuff wayyy cheaper even though its wayyy better.

My battery wires are 12 feet each and go from just behind the mast, under the port seat, and connect to a Minn Kota bulkhead connector. The mating connector is wired to the red and black wires on the motor itself, and it can be detached from the permanently mounted bulkhead connector.

When the battery was located in the cockpit it was inside a black plastic battery box. I drilled holes in the box so I could route a rope from eyes on the cockpit deck into the box, over the battery and back out to the eyes. With the upgraded system I built a watertight box to fit 2 batteries, a battery selector switch, 4 circuit breakers, and, voltage and amperage meters.

I suggest you get a fairly small and light battery that you can take home and leave on a smart charger until next time.

[TIM WEBB]

Tru dat JD - this is why RV's have constant trickle chargers on their deep-cycle coach batteries ...

[talbot]

Thanks. I look forward to any pictures.
Another question:
I've gone to some length to make my boat capsize resistant (waterproof hatch, extra flotation, sealed mast opening). I would like to be able to leave my wiring in the hull and my battery in the cuddy and just plug the motor in when it is needed. Is it possible to install plug fittings that will be waterproof? I don't want to put holes in one of my tanks that might flood the tank in a capsize.

[Alan]

I made some water-resistant (I hope) grommets by cutting a circular piece of rubber from an old inner tube, then securing that to the coaming with a washer made from ABS plastic. I cut slits in the rubber for the wires to pass through. Probably not completely waterproof, but like the cuddy door, I hope it buys some time in a capsize.

[Alan]

Jay,

Where did you get your meters, and are you happy with them?

[TIM WEBB]

OK, a few pix posted in my gallery:

gallery/search.php?user_id=155

[jdoorly]

Hi Alan, I got Teleflex voltmeter and ammeter gauges from Jamestown Distributers because they were the cheapest. They give me the basic functionality I wanted but I do have some complaints about them. They are difficult to read accurately: The voltmeter reads 0 to 16 volts but I'm really only interested in the 10 to 14 volt range, and the ammeter reads -60 amps to +60 amps so the range only shows the +50 amps drawn by the the troller motor but not the 2 amps drawn by the auto pilot, the bilge pump, or the speed and wind instruments. The aluminum mounting system comes scary close to the 50 amp terminal. Next time i would get meters with a bigger face, easier to read dials and an expanded range like 8-15 volts.

Talbot, the bulkhead connector is watertight when the cover is deployed, however if the cover is not deployed and the mating connector is not in place I believe the bulkhead connector, in a worst case, could not allow much more than a small drip if anything. The mating connector has 2 "o" rings to keep water out when it is plugged in. However, you could use a cable gland to pass a wire thru a bulkhead, see http://www.newark.com and search for 'cable glands'. You need to match the wire size to the gland size, as the top portion is screwed in it compresses a rubber bushing around the wire.

Nice pics Tim.

[Alan]

Thanks for the info, Jay. I found this online:

http://www.rc-electronics-usa.com/ammet ... nitor.html

It looks like it would be just the ticket, but it has teeny little wires. You can solder in a shunt, but you have to crack the case (literally) to do this, which caused me to hold off.

[jdoorly]

Alan, that's a neat little dohicky at a reasonable price! However, I read the manual and find the wires in and out are only #14 and max power is 50 amps continuous, higher amps, up to 100A, are only OK for short durations. And, to quote their manual:

"The high current handing capabilities of Watt's Up will be maximized when the Watt's Up's SOURCE and LOAD wires are kept short and cool. Cut the wires as short as is convenient for high current operation. A fan blowing over the wires will help their cooling. At moderate currents there is little heating." a FAN! Looks like its' to good to be true.

[Alan]

Jay,

Exactly what I was thinking. None of us are going to run more than 50 amps continuous, so the gadget would probably be OK, but it would need a high-capacity shunt so as not to defeat the purpose of the high-capacity wires we paid good money for. And the folks selling this device provide very thorough instructions for cracking the case and soldering in leads for the shunt, but that's beyond my skill set at the moment.

I'll probably make do with the battery indicator built into my trolling motor for the time being. I did find an RV battery indicator online, but at at this point, I'm pushing the boundaries of buy-a-Torqeedo territory. Time for me to make do, and think about getting under sail...