I put some new pictures up showing the stock Minn Kota speed control modules installed in the new housing and some tighter shots of the motor mounts.
The shakedown cruse will be this weekend if the truck gets back from the shop and the rain quits long enough for me to make up a tiller.
I went a little light on details in my original post.
Rag-baggers be warned, the rest of this post is to fill in the gaps on a boat that doesn't use canvas for propulsion.
This is the method behind the madness:
The drive system is divided into two separate and isolated units. Each unit will have four batteries, two parallel sets of two 12V 115 AH deep cycle lead/acids in series (Exide NG-31's), each bank drives it's own motor .
(Currently there is only one parallel pair in each of the two banks.)
There will be a separate, isolated charging system for each bank.
I know this actually creates more issues then it solves, but I intended the finished vessel to be self sufficient and long range and I don't feature finding myself cart-wheeling 'dead stick' down a shipping channel.
I'm not exactly an expert in this field but I am a big supporter of the Department of Redundancy Department
...better safe then soggy.
I'm still considering wind or hydro to augment the solar.
I'm not married to the two Minn Kota Endura C2s.
I found a deal on them that was in the budget so went with it.
They're rated with 55 lb. of thrust, according to the spec's each motor alone is supposed to have enough a** to drive a 20 foot 'toon ...we'll see.
If they don't work out on the 'toon, I turn them into the drive for my contender in the Wye Island Marathon.
It's a win win purchase.
The motor mounts are a simple frame built from aluminum parts I got from a canvas shop. They're stock aluminum fittings and pipe used on commercial canopies.
I went with 1 inch pipe (1 1/16 actual with a 3/16" + wall thickness). The fittings at the ends are "wall mount" flanges. The cavities in these flanges were tapered, being tight at the base and sloppy at the mouth. I had to go at them with a drum sander on a Dremmel tool and then hone them out with 120 grit sand paper wrapped around a spark plug socket.
The center supports are cut from 2 x 2 x 1/8 angle stock with 1" x 1/8" flat stock formed around my trusty plug wrench. The flat stock is set into 1 1/2" stainless steel U bolts. The fittings all have bushings cut from 1/16" teflon sheet stock I got thru Amazon.com.
I cut some slugs from 1/8" aluminum sheet with a 1 1/2" hole saw and pressed them into the top of "T" fittings. The bases of these fittings slipped right onto the masts for the motors and secure with 5/16 set screws. The steering arms were cut from 2 x 2 x 1/8' angle and are connected by a tie rod made from eye bolts and 1/4" threaded rod in an aluminum sleeve.
I removed the trim and lock assemblies from the stock Minn Kota mounts, stripping them down to the bare fitting that the motor mast sits in, leaving the steering damper and the depth stop in place. I attached these mounts to the pipe with some 1 x 1 x 1 x 1/8" channel and 1" wood blocks, thru-bolted with five 1/4-20 stainless steel machine screws . The motors swing backwards for storage (up under the deck rather then aft, away from the transom.) I haven't worked out a way to trim the motors yet, but it shouldn't require a real heavy structure with only 110 lb of total thrust.
If I had to do it over I'd have gone with 2 or 3" pipe. There's no deflection in the assembly end to end but there is enough twist in the pipe on the radial axis so's I don't dare drill any more holes in it.
The speed controls looked easy but turned out to be a 3 day P.I.T.A. The odd shape made the mounts for the modules a chore. I didn't take into consideration the heavy gage wiring and should have made the box twice as big as I did. I had to fabricate most of the electrical connectors.
I don't know how much heat the control modules generate, there's not much venting in the original factory housing but I would also turn the base into a heat sink next time, just in case.
There were only 2 problems with the finished control.
First; Elvis wants to turn the piece of deer antler I used for the handle into a chew-toy. He stole it on me twice during the assembly process and he gives it a longing sniff whenever he thinks I'm not looking.
Second; I messed up. I checked everything over and over and over and somehow still managed to assemble the control backwards.
When you push the handle forward, the motors spin in reverse.
I considered reversing the polarity on the controls, but the finished product would end up being a little too much like my life.
...3 speeds forward and 5 in reverse.
I'll just have to learn to live with it
Regards
M
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