Upgrading My Electric Propulsion System

[GrowleyMonster]

A while back, my Kelly KBL48301X controller went snap crackle pop and refused to do anything except blink its little red LED. Turned out a quarter had lodged between the Phase A terminal and B+ terminal. Oops. I decided to turn my misfortune into an opportunity by ordering a 500A controller from Kelly, and then repairing the 300A model to keep as a spare. And with all that juice, and a 12kw ME0913 motor available, slightly used, for a decent price, I decided to go for it. The 5kw motor was enough to push my boat around at over 4.5kt, but More power seemed more better.

Today I finished installing the motor to the same reduction gear I used for the 5kw ME0201014201 motor, and hooked up the controller with 2/0 welding cable which is much more flexible and easier to handle than 19 strand 2/0 cable. The new controller was flashed with a stick shift mod that allows fwd/rev and speed control with a single 5kohm pot. The center position is stopped, all the way one way is full astern, all the way the other way is full ahead. It should make things much simpler than my last control setup. I will mount the pot right on my tiller.

I still need to build not only the user controls but also upgraded instrumentation, a big heat sink for the controller, insulation over the connections, a quarter shield to prevent laundry change from shorting out my controller again, and other miscellaneous refinements. But my initial impression of the new setup is whoa this thing is POWERFUL. Even with the silly 3 blade folding prop I still havent changed, the torque is enough to knock an unwary guest on deck off his or her feet. Should be good for showing off in the marina. If I don't snap my bronze shaft, that is. Nearly instant full ahead to full astern shift. No more noise than my 5kw motor made. I think Im gonna like this. Stay tuned... gonna do some more work on it next weekend.

And now I HAVE to add another bank of golf cart batteries.

[deckofficer]

Do you have plans to upgrade to LiFePO4 cells? All that power from the bigger motor and 500 amp controller would go well without the massive voltage sag of lead under heavy loading.

[GrowleyMonster]

Originally Posted by deckofficer

Do you have plans to upgrade to LiFePO4 cells? All that power from the bigger motor and 500 amp controller would go well without the massive voltage sag of lead under heavy loading.

If I could afford them, I would, but on my budget it is out of the question. The golf cart batts are only $85/ea and so I live with their shortcomings. They are still the biggest bang for the buck right now.

[ArmyChief]

How much solar do you have?

[alctel]

Yeah, could you post more details of your setup if that's ok? How much power do you have in your battery bank?

[GrowleyMonster]

Originally Posted by ArmyChief

How much solar do you have?

None, presently. This winter I will be taking the mast down and buiding a hard canopy over the entire boat. Eventually I hope to have about 2.5kw of solar panels on the canopy, and a 1kw wind generator as well.

[GrowleyMonster]

Originally Posted by alctel

Yeah, could you post more details of your setup if that's ok? How much power do you have in your battery bank?

About 220ah at 48v. So about 10.6 kva/h.

Prop is the original 3 blade folder about 12x8 I think. 2:1 Baldor enclosed gearbox. Motenergy ME0913 BLDC motor, 12kw max sustained power, or roughly 16hp, though it is really a case of apples vs oranges, comparing electric to infernal combustion engine. Kelly KBL48501EY controller, 500A max for 1 minute, 200A sustained. All high current wiring is 2/0. Motor mount built from 3" x 4" x 1/4" angle iron and 1/8" plate, stainless 3/8" bolts. 8 GC-2 6v Golf Cart batteries from Sam's club, in series. 40a quad output charger, each isolated output charging a pair of the batts. Have all the parts for a 30kva manual charger 0 to 130v, just havent put it all together in a chassis yet. I will be using this for equalization charging. I don't have performance data yet because I just completed the installation yesterday, replacing the old 15a charger, 5kw motor and 300a controller with the present setup. Any other details you would like?

[alctel]

Awesome, thanks. How fast can you go at cruise and for how long?

I've been playing around with moving to electric for a while but any design I draw up just can't get the performance I'd like out of it without spending 15k on lithium batteries.

[GrowleyMonster]

Originally Posted by alctel

Awesome, thanks. How fast can you go at cruise and for how long?

I've been playing around with moving to electric for a while but any design I draw up just can't get the performance I'd like out of it without spending 15k on lithium batteries.

Like I said, I just put the new motor and controller in yesterday and all I did was run it a bit tied down to the dock, with alligator jumpers connecting a potentiometer to the controller to control fwd/reverse and speed. So I have not done proper trials yet on the new configuration. But it is over twice the power of the old system, 12kw vs 5kw. I did not achieve hull speed with the 5kw motor but probably it would have, with a bigger controller because the old motor can handle 100A and I was only seeing a max of 60A into the controller. The old setup could give me 4.7kt and at 3kt or less I had a range of about 22 miles I guess. I did not do an actual range test since finding my max range without backup propulsion would of course leave me out in the middle of nowhere. I did run it at various amperages for various hours tied to the dock and calculated some ranges from that, using the current/speed data from speed trials. But that's all out the window now.

A good cruising speed for an electric drive displacement hull is half your hull speed or a bit less. Sure, you can go faster, but not for long. Unless you want to buy a LOT of batteries. This is approximately 1.34 x the square root of the waterline length. Length in feet, hull speed in knots.

$15K will get you a rather nice turnkey system with a high performance battery bank. If you have the bucks, it is worth considering. But if you got to go cheap, you can be all in at less than 1/5 that cost for a boat 30 feet or less. After selling my old Atomic, which still ran, I had about $2000 or a bit more in the original project, I guess. I don't remember exactly. I got a great deal on a motor (TWO motors actually, for a spare, but Im not counting the cost of the second motor) and the controller I got in a kit with a mounting plate/heatsink, contactor, fuse, wiring harness, etc. Batteries came from Sams Club and that is where I really went bargain basement cheap. Then there was all the 2/0 cable for phase cables from controller to motor, same size wire for battery cable, lugs, steel for the mount, bolts, reduction gear, two couplings and a short piece of shaft, odds and ends to build the controls and instruments, and other various doodads. The new setup uses a much more expensive motor, around $700 vs $400. And a more expensive controller, by an increase of a couple hundred bucks. I retained the original prop but I do need to change it for a fixed blade prop. So yes, you can definitely beat the 15k figure if you want to make some compromises and do some of your own engineering and all of your installing and engine and fuel tank removal which can be a PITA especially doing it by yourself which is what I did. And you need to spend at least a year researching and figuring and mentally walking through it and considering the consequences of each step of the process and what can go wrong, which is basically EVERYTHING haha.

[senormechanico]

We need pictures. Pretty Please??

And as Deck Officer said, (in code words) LiFePo4 is waiting for you to discover the next horizon of performance.

[GrowleyMonster]

Originally Posted by senormechanico

We need pictures. Pretty Please??

And as Deck Officer said, (in code words) LiFePo4 is waiting for you to discover the next horizon of performance.

Golf cart batteries are all I can afford. Period. The performance of LiFePo4 batts is totally irelevant if I can't afford to buy them in the first place. Lead works just fine. Just takes more pounds of them, weight being the one thing I don't have to worry too much about. Trust me, if someone wanted to donate a 1000ah 48v bank of the good stuff, I would certainly install it. Unfortunately I am the buy guy, not someone else.

Pics this weekend. I sleep on the ship during the week and sleep on the boat on the weekends. Transportation weekday mornings is a hassle so I am only home on the weekend. But you can search for the original thread from last year when I installed the original electric drive. There are pics, of the old Infernal Confusion engine coming out, and the electric being installed. Ill post pics of the new motor and controller Fri or Sat. But looks just like the old stuff, only bigger.

[GILow]

Hi GrowleyMonster,

I am very interested in your setup, and I am curious about the throttle control. Does the software have some kind of "damper" in it to smooth the variations in resistance sent from the throttle/gear potentiometer? I have a car that is an early "drive by wire" system and the throttle position sensor is a PITA. It occured to me, when reading your description of the take-off torque that as the potentiometer ages it could become as tricky to drive your boat as it is to drive my car. A simple averaging circuit or a software loop that limits the rate of throttle change could overcome this.

Matt

[IdoraKeeper]

What? Take the mast down? Now what! Good grief. No more sailing?

[GrowleyMonster]

Originally Posted by GILow

Hi GrowleyMonster,

I am very interested in your setup, and I am curious about the throttle control. Does the software have some kind of "damper" in it to smooth the variations in resistance sent from the throttle/gear potentiometer? I have a car that is an early "drive by wire" system and the throttle position sensor is a PITA. It occured to me, when reading your description of the take-off torque that as the potentiometer ages it could become as tricky to drive your boat as it is to drive my car. A simple averaging circuit or a software loop that limits the rate of throttle change could overcome this.

Matt

These are microprocessor driven controllers. And I am not using a hall sensor or optical throttle control. The pot is just a standard pot, not spring loaded so it is hands free until an adjustment is needed. A new pot is two bucks at Rat Shack or even less from Mouser or All or any other online vendor, and a couple of spares are on my boat and are a good idea for anyone else to keep on their boat, who is not using a turnkey throttle control. Anyway throttle response is as smooth as the hand that twists the knob. There are three modes... torque, speed, and balanced modes, which ramp up slightly differently. But mostly, turn he knob gently, accellerate/deaccellerate gently. Slam the knob right to the stop, and you get the rocket-sled effect. It is as it should be.

[GrowleyMonster]

Originally Posted by IdoraKeeper

What? Take the mast down? Now what! Good grief. No more sailing?

Thats right. It would shade my solar panels, and it is in the way of the canopy. I like sailing but this will be an electric boat, all the way. And an energy independant floating home where I can still have my air conditioning and showers and cell phone charging after our next Katrina, without scrambling around looking for fuel.