Electric Outboards

[Michael Rogers]

This discussion started under "Not all Swallowboats are Bayraiders'. I've taken the liberty of continuing it here, as being 'tidier' - or something. Hope that's OK by those interested

I've had information back from Outboards Direct (see link provided by Peter Taylor). They talk about thrust, not HP, and have drawn my attention to a Yamaha electric (30lb thrust), which they price at £226 (including VAT and delivery), and the Mariner with least poke of the three on offer (40lb) at £301 (ditto). Judging from their battery pack weight remarks, I suspect they supply some sort of lead/acid batteries, and they suggest that a 90 amp (that's presumably amp hour?) battery will run one of these engines at full throttle for 1 1/2 hours.

Even if one went for a pricey lithium pack, which seems to have to come from the US at present, that would make the whole caboosh WAY cheaper than the smallest size of Torqeedo, currently (excuse the unintended pun) about £1100.

I'm glad you're confused as well, Ian. Someone who I am sure would illuminate the thrust/HP issue for us is Jeremy Harris, who used to contribute very eruditely to this forum in years gone by, but who has recently been more than busy building an eco-house in (I think) Shropshire. Are you there, Jeremy?!

Michael

[Graham W]

According to the Torqeedo website, the Torqeedo 1003 produces static thrust of 68lbs.  They also note that "Torqeedo static thrust measurement is based on globally valid ISO standards. Static thrust figures for conventional trolling motors are measured digressively, which results in higher values. In order to compare Torqeedo static thrust data with conventional trolling motors, add approximately 50% to the Torqeedo static thrust values."

So, taking them at their word, the 1003 possibly produces about 100lbs of thrust in comparison with the Mariner's 40lbs that Michael mentions.

After a month using the Torqeedo on my BR20 in the Ionian, where the weather is mostly good and the sea currents negligible, I have come to the following unoriginal conclusions:
1. In any sort of contrary wind, the throttle setting required to stop the bow falling away is so high that the range is severely compromised.  So although the 1003 is possibly equivalent to a 3hp petrol outboard as claimed by Torqeedo, this is only true for a short distance, after which and unless you have a spare battery, it is 0hp
2. The whiny noise made by the gearbox even at low revs is grating on the nerves over even short distances.  It sounds like a large Kenwood food mixer.
3. The electrical connections, which have to be dismantled at the end of every day for charging and/or discouraging theft, are difficult to screw back together the next day without getting an "E30 error" (faulty connection) message, especially if salty
4. If the boat is used as a taverna taxi, the slow speed (to make sure we can get back without exhausting the battery), whiny noise and general range anxiety give rise to numerous sarcastic comments from my passengers
5. Because the Torqeedo was originally designed for the freshwater Bodensee, I doubt that it would last very long in a strongly saline environment (eg the problem with the thrust washers mentioned in Peter's library article on the Torqeedo)
6. Its plastic propeller is less robust than the steel ones on petrol outboards and easily picks up chips and nicks on its outer edges
7. Given how quickly the battery can be depleted, the time required to recharge with the standard charger (>15 hours) is ludicrous.  A faster charger is supposed to be available at extra cost but really ought to be supplied as standard and is still on back order in the UK, nine months after it was first announced

So in future the Torqeedo is only going to be used where petrol outboards are not allowed (Bala, Rutland) and where I want to keep weight down and I know that there are safety boats about (Sail Caledonia).  Otherwise like Peter in the update to his library article (about halfway down), it's back to the Mariner 6hp stinkpot with external 20 litre tank for me.

Peter's article can be found at http://www.swallowyachtsassociation.org/?page_id=820

[Michael Rogers]

There's nothing like experience!

Question - what's the difference between an electric outboard and a 'trolling motor'? The latter comes across as a term of subtle abuse when used by Torqeedo! How do they know that the opposition use sneaky measurements of thrust, rather than 'globally valid ISO standards'?

Graham, I'm complimented by identification as the author of the learned article on Torqeedos in the Library. I'm sure the author won't mind too much, I haven't checked who it was, but it certainly wasn't me.

Michael

[Michael Rogers]

I've checked - the main article is by Peter Taylor. The postscript is by you, Graham!

[Graham W]

Michael,

I think the main difference between the Torqeedo motor and the trolling motors is that the latter don't have an integrated battery and possibly don't have quite the level of electronic control that the Torqeedo boasts.  Otherwise the principle is pretty much the same - an electric motor and gearbox in a casing underwater fixed just in front of the propeller.  Torqeedo are trying to present themselves as direct competition for petrol outboards and I think you need to go into that one with your eyes open.

It was of course Peter who wrote the article and I've now changed the attributions in my original post.  In my defence, I have just trailed the boat from Switzerland to Shropshire in 18 hours (and through half of Italy the day before) and am feeling a bit gaga!

[Michael Rogers]

An integrated battery is a fine idea, except that, so far as range is concerned, quarts and pint pots come to mind.

According to Outboards Direct, the new Mariner electrics have pretty good electronic control (better than Yamaha, they told me). And I believe Mariner do quite good outboards generally, so should know what they're doing.

I'm not sold on the idea yet, and even at non-Torqeedo prices I still have some pennies to save. It's very strange, given the acknowledged superiority of Lithium battery performance, that there doesn't seem to be a UK firm going big on retailing largish Lithium battery packs. US prices vary widely: and an Aussie firm are selling what are probably Chinese packs on eBay. There are golf buggy packs available, but how does '36 holes guaranteed' relate to nautical mileage range?!

I wish you a speedy recovery, Graham, from your towing exertions. Several years back I towed my previous boat (Storm Petrel) to and from Lake Garda. I took 2 1/2 days going out and quite enjoyed it. For various reasons the return had to be done much more quickly (like you, about 18 hours as I recall), and quite a lot of strong coffee was needed.

See you at Mylor!

Michael

[Graham W]

Michael,

It looks like the weather at Mylor won't be too bad.

What the adverts call a 36 hole battery seems to be normally a 12V 22Ah one, which translates into 264 Watt/hours.  The Torqeedo's battery is 29.6V 18Ah, which is 520 Wh, or twice as large.  As a comparison, a normal car lead acid battery would be 12V and around 40Ah, which gives 480Wh.

Here are a couple of UK companies that specialise in lithium batteries:
Upmarket and expensive http://www.tracerpower.co.uk/tracer-lifepo4-battery-packs.html
Cheaper but still pretty good  http://www.batterymasters.co.uk/Catalog-LiFePO4-Batteries_299.aspx

[Michael Rogers]

I'd better shut up (Chorus of 'Yes, please do!" from the ether, whatever that is) but -

I've just used the 'Search' facility, which works a treat (amazing!). With it, I've been able to re-find and re-read a thread called "Better things are electric", which was in 2010. It's useful, including several lengthy contributions from Jeremy: you'll see what I mean about him knowing what he's talking about. And SURELY there have been significant advances in battery technology in the last 4 years?

(If Jeremy's know-how is of special interest to anyone, most of his on-line stuff on motors, electrics, batteries etc has been on the Home Built Boat Rally (HBBR) forum, because he has had several goes at the Makita Cordless Canoe Challenge (at the Beale Show), and has been very generous in sharing the results of his experimental and development work.)

Stop press - while pecking this out, Graham's latest post beat me to it. Thanks - I'll follow up those UK battery links.

Michael

[Julian Swindell]

I can't help thinking that if we all used electric outboards as the norm, and someone invented an outboard that could run for an hour on a litre of fuel, which you can buy anywhere in the world, and can carry a spare five hours worth in a little green tank, we would all ditch our electrics in a week and buy one of these new wonder machines...
I have no experience of electric motors, but ultimately, I want a motor which will give me enough power, for as long as I need it, to get me out of the mess I have got myself into. I know the noise and smell is awful, but when it gets you away from the rocks that the wind and tide were throwing you onto, it is the most wonderful sound in the world!

[Michael Rogers]

That, Julian, is fair enough, as things stand now. However, I think there's little doubt that the coming breakthrough in battery (or fuel cell?) design will mean that use of electric outboards (and inboards, and cars, and .......) will take off. There's already nothing wrong with electric motor or propellor technology, it's just the equivalent of the can of petrol which isn't up to it. And just think of doing away with the noise, and the smell, and the maintenance - AND being able, first to claw your way confidently off that lee shore, and secondly to motor quietly and efficiently back to your mooring through the mounting storm.

So, particularly if you're a closet petrolhead (nothing wrong with that), do enjoy the stink and the noise of now. I'm just wondering whether to join the pioneers of quiet confidence tomorrow. Haven't decided (and can't afford it) yet. Meanwhile, I really must varnish those oars.

Michael

[Graham W]

Michael,

Maybe it's me, or the Torqeedo, or both, but the whiny noise of my electric motor is really intrusive - if it was properly quiet I would like it better.  I've measured the noise level at nearly 90 decibels at the helm.  Considering that the important moving bits are all under water, I should have thought that it would be quieter.

I'm sure that an updated version of the 1003 ought to be quieter and with better range. However, I can't help feeling that Torqeedo have got bored with small motors, favouring instead their new large motors and hybrid drives, which are more glamorous and doubtless have higher margins.

Panasonic and Bosch (an investor in Torqeedo) have done great things with motor and battery technology for electrically-assisted bikes, which are popular on the continent.  It probably needs someone with similarly deep pockets from outside the marine industry to do the same for small outboards. How difficult can it be?

[Peter Taylor]

I've only just noticed this thread!  I agree with Graham that the whine of the Torqeedo is very annoying - other electrics are much quieter and although they may not be as powerful as the Torqeedo is at full power - remember that the Torqeedo's full power is practically unusable.

Have tried my best to use the Torqeedo on my BC20 I finally had to admit defeat and buy a 6hp Tohatsu. You can read my reasons at some length on my blog so I won't repeat them here - look at... http://www.seatern.org.uk/SeaternDiaries/equipment_fit.php
and the articles under "outboard motor" (curiously enough!).

I've been looking at fuel cells for Seatern but they are horribly expensive and ones of a practical size are only a way of recharging your battery; they would not provide a primary power source for an electric outboard. I've concluded that if you filled the water ballast tanks with batteries you'd probably have enough power for electric to be practical - but that negates the idea of removable ballast!

Peter

[Peter Taylor]

Having written the last post I found the latest copy of Practical Boat Owner (October 2014 no. 579) in the letterbox with a comparison of Electric and Propane outboards against a Mariner SailMate 4hp. The electrics were the Torqeedo 1003S and Cruise 2.0TS and the "Haswing Proturar 2hp" (the latter is one of these more powerful trolling type motors).

There was no definite conclusion. The Cruise 2.0 "felt like a proper, well sized engine" for the 23 foot test yacht (suggesting the Travel 1003s didn't).  But it is expensive and needs an expensive, heavy battery, and you still only get about an hour's run time at full power. The Haswing gave similar performance to the Torqeedo 1000 at cheaper cost. Notably its bollard pull was greater. However looking on the distributors web site...

http://www.marathonleisure.co.uk/product.php?xProd=206017&xSec=1554

it takes up to 61A at 24V which means that the motor is about 1500W  compared to 1000W for the Torqeedo, i.e. less efficient. Using two 110Ah 12V batteries at full power you would still only get order 40 to 50 minutes. And discharging lead acid batteries at that rate is not good for them (and needs some largish cables*). Using 24V lithium ion batteries might be a better bet (but at increased cost and you still need big cables).

Propane might be a good alternative to petrol if it's allowed where petrol engines are banned. PBO tested the Lehr 2.5hp and 5.0hp.

Peter

* anyone considering electric outboards with detached batteries should remember that heating goes up with the  square of the current - large currents need big cables and good connectors to avoid the risk of fire. In my experience in some cases the cables supplied assume that the motor won't be running continuously at full power.  Be aware!

[Graham W]

Further evidence that the Torqeedo 1003 is not suitable for use at sea: during the Swallow Raid at Mylor last week, the wind really got up, gusting at up to about 40 knots.  Most boats (except Gladys of course) dropped their sails and motored back to base.  Turaco sailed most of the way back and we then dropped sail just outside the moorings.  Even with the Torqeedo at full throttle, we made very little headway and the motor's battery charge fell off a cliff.  When the battery was about to expire, we had to grab one of the moored boats and wait for Matt to rescue us in the safety RIB.

The Torqeedo 1003 is alleged to be equivalent to a 3hp petrol engine.  I don't know if any of the other Swallows had one of those little petrol Suzuki 2.5's (or similar) but if they did, they got home under their own steam and we didn't. 'Nuff said.

[jonno]

Ella has the little Suzuki 2.5, Graham.  It got us home that day.  It has its disadvantages - but it's light.

John