Electric Motor

Moderator: GreenLake

Electric Motor

Postby GreenLake » Fri Jun 22, 2018 11:21 pm

I've been given a demo unit of the EP Carry (Electric Paddle). Over the next two weeks, I will fit it to the boat and then try it out in a variety of settings and conditions. It's already passed its first test: while trial fitting it, I was interrupted by a neighbor. After we talked for 15 mins, I noticed I was still holding the motor. That's light weight.

Their normal/short shaft model fits the DS transom, and the clamp fits in the "motor well" of my DS1. In that position, the propeller is just about 3" behind the transom, and even though it is wider than that for a trolling motor, it is pretty much entirely out of the way of the rudder. It looks like you'd have to do a very hard port turn to get rudder and propeller in contact.

I have a bit of trim at the upper edge of the transom, so the surface isn't entirely flush. I plan to cut a plywood shim, which would also allow me to mount a fleece pad to protect the paint job (my transom has been painted over). When that's done, I'll start field trials.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby GreenLake » Sun Jun 24, 2018 2:02 pm

So, the plywood shim worked but would need to be glued or otherwise fixed to the motor or boat for regular use. Too fiddly otherwise. With shim in place the motor mounts firmly.

Light winds on the lake, with patches/periods of near calm: perfect time for testing.

From the specifications, I see that the motor draws about half the current as a trolling motor. They warned me that a DS would be at the upper end of the range they designed that motor for. The big question is, with that small a battery and low power consumption, can it move the boat at all?

Let's find out.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby GreenLake » Tue Jun 26, 2018 12:36 am

Here's a picture what it looks like at the dock.
EP+DS.png
EP+DS.png (119.8 KiB) Viewed 3353 times

Their normal/short shaft just about fits the cavitation plate to the waterline. Will that work in waves?
Separation from the rudder looks good.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby GreenLake » Wed Jun 27, 2018 6:39 pm

Time to put the motor to the test. Rigged the boat but left the sails down for the first test. Slight offshore wind.
Motored out the channel toward open water.

First impressions: the actual motor is at the top, like a conventional outboard, with a driveshaft and some gears in the lower unit. (The gears are open, because they are water-lubricated). In contrast, a trolling motor has the actual motor in a 'bulb' at the bottom of the shaft, with only the electronics at the top. This accounts for one difference: the motor is more audible than a trolling motor, but still pretty quiet in contrast to a conventional outboard. There's a bit of vibration and I learned that I need to be really good about clamping the motor, or it will shake itself loose.

First test was to go to maximum power with a fully charged battery and check the GPS for maximum speed with sails down. I went some stretch downwind, and another upwind to be able to isolate any contribution from the wind, but needn't have bothered. Both directions gave me a pretty even three knots.

Next test, raising sails.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby GreenLake » Fri Jun 29, 2018 11:34 am

A light breeze had come up, just the kind that might make for an enjoyable evening sail or drifting along while watching the sunset.

I set my trusty tiller tamer (bungee cord), put the motor on what I guessed was half speed. The dial isn't marked but I adjusted until I got two knots via GPS.

Raised main and jib. Don't usually do it that way, so almost ran out of sea-room before I had them up. Once the main was nearly up, it did contribute something, and I had to adjust the tiller a bit. The GPS track shows the boat speeding up some. Looks like we weren't going straight upwind, or the wind shifted and we got to "motor-sailing" a bit.

I turned around and raised the jib going downwind, or at least across, with the main all the way out. At the point where everything as in trim the GPS track shows 4.2 knots. No longer 100% sure in retrospect whether with or without help from the motor --- because engaging and disengaging this motor is so effortless.

The motor is tilted up out of the water with a very simple pull on the control knob at the end of a somewhat long-ish tiller arm for the motor.

Pulling it up (and deploying it again) is super easy, just one pull and it tilts up, and one push and it goes back down. Because it is so easy, it's ideal for the kind of situation I had on the test run, where there's generally some wind, so you can sail the boat, but there are places with no wind or traffic that you might want to motor through.

For that reason, I decided against continuing the test on more open water and instead picked a course under some bridges and through a bit of canal.

So I turned around and then sailed towards the first bridge. Reached 3.8 under sail broad reach turning into a run, which shows pretty much the best that light breeze had to offer.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby GreenLake » Sat Jun 30, 2018 10:20 pm

The next part of the test involved crossing an extended wind shadow under and between several bridges, as well as traversing a steep sided bit of canal. All of this with the sails left up. There were some puffs to keep the sails, if not filled, then not totally slack, yet the GPS registered a steady 3.0 knots across the more open water. In the canal, a steady stream of passing and oncoming motorboats at times generated confused wakes that, at one time, swapped into the little "motor well" at the end of my transom.

Luckily, the battery is completely waterproof.

Bouncing around did raise the propeller partially out of the water, I could hear the motor speed up when that happened. Whether just because of that or whether the other boats also set up swirling eddies in the canal, the GPS readings were generally lower, down to 1.7 knots for a bit.

This part of the test allowed me to get a good comparison to my 40# 12V trolling motor, which I use with a Kipawa 3-bladed "high performance" propeller. On old GPS tracks I find the same passage with maximum speeds of 2.4 to 2.5 knots.

As tested the EP is half a knot faster, while drawing less than 1/2 the amount of current. Expressed as kw / knot the energy efficiency is almost three times that of the trolling motor.

The low weight and energy efficiency of the motor are impressive, and the latter improves the weight picture by allowing the use of a smaller battery. The easy, single pull operation to deploy the motor means that you are never tempted to drag it through the water to save raising it, and makes the motor ideal for variable conditions, when you want to sail where you can and motor where you have to. Compared to the 40-45 mins that I get out of the trolling motor per 80Ah battery (not going below 50% charge), the EP promises 60 mins. At the higher speed, that translates into quite a bit of extra range, perhaps almost as much, on a single battery, as I got out of two big batteries with my trolling motor.

I wasn't able to fully test the range (to the point where the battery controller would shut of the motor to preserve the battery), but I think I did almost 2.5 nautical miles, mostly at full speed.

With all battery operated motors, there's the trick that going at half-power will extend your range significantly. Here, I wish the control knob had a more positive identification on the dial where that half-power spot is, and a small indent or something to let you "feel" when you reached it. As it is, setting the speed with the GPS is about the only way.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby GreenLake » Sat Jun 30, 2018 10:29 pm

While I found a nice pocket of wind near the destination of my cruise and spent an enjoyable hour gliding soundlessly about in the sunset, I wondered about whether I would take the plunge and do this upgrade.

A number of questions remain open. One, how much would performance be affected by wind? I'm not contemplating a motor to use as a way to get off the water in rising winds. That's what reefs are for. But there may be cases where pushing for a bit against some wind is useful. Like docking, or making it down the channel on a day the wind is on the nose.

Some more tests are planned for that. Stay tuned, this story hasn't reached a final conclusion yet. Let me just say, I had some tantalizing e-mail exchanges with the guy behind the design, and it may be that he has some additional tricks his sleeve.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby GreenLake » Fri Aug 03, 2018 10:56 pm

As promised, more tests were done, and more are to follow.

One test consisted of taking the battery on longer daysail (see the thread "Genre:party cruise" for the type of outing). It involves crossing several connected bodies of water, including those that I already tested the motor in. The problem this time of year is that the winds can be fickle, and also have a tendency to "lift off the water", especially for the return, leaving some bays and cuts with mirror smooth water. My previous setup with two 80Ah batteries and trolling motor, did not always have enough range to get me back; to get under bridges the motor is needed on the outbound leg and that can make things tight if the winds don't get me across at least half my return distance.

This year was no exception from the general pattern, in fact, on the chosen day the wind forecast was the weakest. One thing that made a difference was that the battery is so light and charges so fast, that I could take it with me on the other end and plug it in while I attended the party and start my return with a fully charged battery.

We saw some decent wind on the lake when decided to start our return, but with some inevitable delay ended up hitting the water just when the wind died. We motored out into the main lake where we picked up inconsistent zephyrs that allowed ghosting but no progress. We enjoyed the full moon a bit and then spied a promising wind patch and motored to it. Got a nice steady breeze to get us across the bulk of the lake and through half of one of the bays. But under the bridges and some of the smaller bays we had to motor.

The battery is rated for 60min at full power; we did 48min and then another almost 30 mins at half power (which is a bit slower, but much faster than 1/2 speed, perhaps 3/4). That got us home. As full speed with the test motor is a bit faster than with my trolling motor, we can round this result to say that we could have motored for 80 mins with the same speed as with the trolling motor, something that would have put both of the deep cycle batter down to half charge. That from a single 6.4lb battery.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby tomodda » Thu Oct 18, 2018 7:35 am

GL:

Thank you for these posts on the EP Carry. I'm seriously considering one. Question for you - what is the maximum speed you have gotten from the EP on the DS1? I spoke with Joe Grez last night and he said 3.8 knots in testing on a newer DS. Does that gybe with what you've seen?

Obviously, I'd be using an engine, electric or otherwise, mostly in dead calms or maneuvering around the boat ramp. Not really concerned about raw speed. I'm a sailor! If I wanted to get somewhere fast, I'd drive.. or even walk ;-) But seriously, I can see trying to hustle to shore before a squall line or work against a current in a channel, so max speed might matter on occasion.

Amy input would be much appreciated.

Tom
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Re: Electric Motor

Postby GreenLake » Thu Oct 18, 2018 11:07 am

Joe and I were going to test some upgrades, but something with the test setup didn't work. That was quite some time ago, because schedules prevented a repeat. He was clearly interested in figuring out the best configuration to use with a DS and may have had a chance to do some tests on a different boat since then.

In the original configuration as delivered to me, the motor was a tad more effective at driving the boat than my 40# trolling motor. The convenience factor was clearly in favor of the EP Carry. The motor is lighter than a trolling motor and the battery pack looks like a large fanny pack with about 6# of weight. That's a far cry from having to drag a lead-acid battery.

If Joe says he tested something on a DS (where DS stands for the O'Day DaySailer rather than some "daysailer", just make sure), then in my experience his numbers would be reliable. The motor can apparently be reprogrammed to give higher output (at the cost of some lower run-time), and, apparently, he was working on a propeller optimized for that.

His design depends on careful calibration of battery parameters, motor power and propeller to achieve amazing propulsion per watt.

I would love to have 3.5 or even 3.8 knots top speeds for some tricky canal and bridge traverses, but even with the 3.0-3.1 knots I measured, the motor came out ahead (and I can do my annual trek on one battery, as long as I have wind on the more open parts). That would work well for me.

My plan was to get in touch with him after my schedules cleared, but it looks like you may have beat me to it.
~ green ~ lake ~ ~
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Re: Electric Motor

Postby tomodda » Thu Oct 18, 2018 12:08 pm

GL:

Thank you again. Joe was very kind and informative on our call. He's certainly putting some thought into how to extend the use of his motor for us small-boat sailors. Good to know from your note that his ideas are along the lines of a software change and propeller upgrade, so it's not a "rip and replace" upgrade.

Anyway, I"m not really worried about speed. As you wrote, the attraction of an EP carry for me is handling - certainly more convenient than a gas burner and no heavy lead acid batteries to deal with compared to a trolling motor. Generally speaking, I so hate hanging off the stern of a boat fiddling with an engine, that I'm willing to pay $1600 to free myself of that. Actually, I'd rather just row, but I'm getting older....

I did discuss range with Joe, as that interests me more than raw speed. I can certainly see the wind dying out while I'm 10 miles out on the Pamlico, seen it happen. Don't mind spending 3 hours puttering back slooooowly. Do mind this EP thing running out of juice on the way. Joe gave me some ideas - besides throttling WAY back, he suggests a solar panel up to 100W. Wont keep me running indefinitely, but close enough for my purposes. Sounds like a fun "next year project." We also discussed how to clear the prop of weed - tilt the engine up and give it a whirl! Like making chopped salad :)

Question- how has the reliability been? Any times that it wouldn't start up when you've wanted it to?

Tom
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Re: Electric Motor

Postby GreenLake » Thu Oct 18, 2018 5:09 pm

In my experience with all electric motors, the one reliability issue is a discharged battery when you are setting out. Requires forethought to hook it up before you go.

Otherwise, the EP Carry is not different in that it always starts.

(You do need to put the little key in for 3 sec).

The single lever deployment is so quick that you can have the motor raised out of the water, and the key removed, and still get in back in, key inserted with 3 sec wait, in time for all but totally "last moment" maneuvers. There's no need to drag it through the water because there's some traffic nearby - you'll be able to deploy it more selectively when needed (and as lifting it is equally painless, you'll pull it up the minute it's not in active use - truly a motor for sailors).

My regular outings that have always required some motor are of 6mi range, with at least 50% usually getting some breeze, so effectively I need to cover about 3nm. I was able to do that at full speed (at the 3kn max power setting as on the test motor I had) on a single battery as I reported. For the trolling motor, I needed two batteries for that, as the effective run time there was more like 40-45 min per battery (and with no battery protector guarding against too deep discharge, unlike the EP Carry).

If I had to do 10mi regularly, I would spring for a second battery.
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Re: Electric Motor

Postby tomodda » Thu Oct 18, 2018 9:28 pm

Sounds perfect thank you for the report. My local lake has quite a few boat ramps that are right by bridges. The motor boaters drive in over the bridge, pop their stinkpots in and slip back out under the bridge. I can see this little engine allowing me to join them, and raise my mast on any bit of shoreline just beyond the bridge. Opens up a lot more sailing grounds for me!

I've been lucky, a double windfall this week... I got a very unexpected cash bonus at work and, more importantly, the Ministry of Finance is allowing me to blow it all on the boat :) So EP Carry egg-beater it is!

Tom
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Re: Electric Motor

Postby GreenLake » Mon Oct 29, 2018 6:35 pm

~ green ~ lake ~ ~
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Re: Electric Motor

Postby GreenLake » Tue Jan 22, 2019 7:25 pm

I gave myself a late Xmas present and took advantage of the end-of-year promotion.
The production unit came with a lock, which should help in moderate risk situations, can also be used to "secure" the battery by passing it through the webbing loop on the battery carrier pouch.
Nothing else seemed much different from the demo unit. The flat water/calm speed still clocks in around 3.1kn (but there's a downloadable patch to the software that would allow higher power; but I need to get hold of an iPhone to try that).

I did discover that agressively moving weight forward (standing on the cuddy, I got a noticeable uptick in GPS speed to around 3.3kn).
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