Electric outboards for tender (budget, not Torqeedo) - your experiences please

pvb said:
Trolling motors are OK on lakes, etc, but they're not particularly suited to any sort of tidal waterway. The Torqeedo is great, I have one for my inflatable and I'm very impressed by it. If only they could improve the legibility of the LCD display....
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Like others we bought a Torquedo and haven't used our 5hp four stroke for two years. I can see a trolling motor working with a smallish battery with a handle but it would be a lot less convenient or easily rainproof. Hate the LCD display so tend to just check it at the beginning and end of each dinghy trip. The fact I can charge it straight from my domestic battery bank by inverter (I know) is a big bonus, and only needed after five or six typical return trips of a quarter mile or so.

So to me Torqueedo is more about convenience than a magically advanced technical solution compared to a trolling motor (plus a chance of more poke occasionally).
 
You can charge the Torqeedo battery directly from the ships battery, no need for an inverter. They sell a lead or make one, cigar plug direct to Torqeedo.
 
foeu said:
My response was to Sailorman who said that battery outboards were only useful on a lake.
I'm aware that the OP doesn't want a Torqeedo. Not going to be easy to furnish his requirements.
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Seems to me that Roger Shaw has come up with the goods with a converted electric drill. But I'm not sure from his pic whether there's a long enough lead...
 
pvb said:
Yes, it should be helpful in reinforcing the fact that a cheap trolling motor isn't going to give much satisfaction.
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To be honest that fact didn't require a great deal of reinforcing. The gist I'm getting is that a trolling motor of sufficient size will push an inflatable tender against the tide, but the size of the motor means only a heavier battery will give the motor any decent range. As I mentioned earlier on, If I see a cheap one on eBay I'll get it just so I can experiment a bit with battery size. Certainly not interested in lugging a 110Ah battery down to the river every time I wish to use the outboard.

My interest in electric propulsion has been sparked by a) my idiosyncratic Tohatsu, and b) having a go in my mate's Nissan Leaf (electric car) the other day. Sort of a road to Damascus experience to be honest - if I was spending £10k on a second hand car (his was £9k) there is not a chance I would be looking at internal combustion engine powered cars. 19th century technology as far as I'm concerned.
 
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fredrussell said:
To be honest that fact didn't require a great deal of reinforcing. The gist I'm getting is that a trolling motor of sufficient size will push an inflatable tender against the tide, but the size of the motor means only a heavier battery will give the motor any decent range.
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That's if you go lead-acid. The Outboards Which Must Not Be Mentioned (TOWMNBM) use Li-ion batteries, which explains their insanely high prices (their batteries include GPS receivers, for some reason, which can't help). Prices are coming down, though - http://www.amazon.co.uk/LI20-12-LITHIUM-MOBILITY-ELECTRIC-VEHICLES/dp/B00SJB5XSG is a 12V, 20Ah Li-ion battery for £190 delivered. It only weighs 3kg and will give you 20 minutes of full thrust on a Minn-kota 55lb model. Still expensive, of course, but I don't think TOWMNBM are going to have the market to themselves for long
 
fredrussell said:
My interest in electric propulsion has been sparked by a) my idiosyncratic Tohatsu, and b) having a go in my mate's Nissan Leaf (electric car) the other day. Sort of a road to Damascus experience to be honest - if I was spending £10k on a second hand car (his was £9k) there is not a chance I would be looking at internal combustion engine powered cars. 19th century technology as far as I'm concerned.
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It is a mistake to try and translate developments in road transport into a marine environment. The two have developed on completely different lines because the requirements are different. There has been minimal development of electric propulsion for boats for a number of reasons, particularly the almost complete absence of any state funding or incentives.

In the very limited applications of electric power to boats the technology used is completely different from that used in road vehicles. The two main successful applications are low speed, short duration inland waterways use and supersize cruise ship electric propulsion pods. The former uses technology dating back to the 19th century and the latter has some connection with dual power source railroad propulsion.

The fundamental problems are power and range. Electricity is poor at converting energy into propulsion and current energy storage media (batteries) have limited capacity. These constraints are not limiting in some applications where weight and space for storage are not an issue, the range requirements are not demanding and there is a convenient means of charging. L ion batteries reduce the energy storage constraints, but producing enough power to be useful on a boat taxes even them. As already mentioned, Torqeedo is the only product that has managed to provide an acceptable compromise, but at a high cost.

Do not expect any significant change in the near future. Boat engines have always been a derivative of road or industrial vehicles as the market is far too small to justify its own unique solutions. Current road vehicle developments using electricity do not lend themselves to adaptation to boats.

So while the unique features of electricity, particularly lack of noise, minimal pollution at point of use and linear power delivery are attractive it will need a massive leap in technology to overcome the energy acquisition and storage constraints.
 
Tranona said:
It is a mistake to try and translate developments in road transport into a marine environment. The two have developed on completely different lines because the requirements are different. There has been minimal development of electric propulsion for boats for a number of reasons, particularly the almost complete absence of any state funding or incentives.

In the very limited applications of electric power to boats the technology used is completely different from that used in road vehicles. The two main successful applications are low speed, short duration inland waterways use and supersize cruise ship electric propulsion pods. The former uses technology dating back to the 19th century and the latter has some connection with dual power source railroad propulsion.

The fundamental problems are power and range. Electricity is poor at converting energy into propulsion and current energy storage media (batteries) have limited capacity. These constraints are not limiting in some applications where weight and space for storage are not an issue, the range requirements are not demanding and there is a convenient means of charging. L ion batteries reduce the energy storage constraints, but producing enough power to be useful on a boat taxes even them. As already mentioned, Torqeedo is the only product that has managed to provide an acceptable compromise, but at a high cost.

Do not expect any significant change in the near future. Boat engines have always been a derivative of road or industrial vehicles as the market is far too small to justify its own unique solutions. Current road vehicle developments using electricity do not lend themselves to adaptation to boats.

So while the unique features of electricity, particularly lack of noise, minimal pollution at point of use and linear power delivery are attractive it will need a massive leap in technology to overcome the energy acquisition and storage constraints.
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Excellent post. There seems to be a lot of knowledgable people out there with an interest in electric power so how long before an amateur comes up with practical design? Apart from Li-on batteries (and Li-po) there are more and more brushless motors and other developments around; I first came accross them in electric model car racing and now see them featured in power tools. Or has it been done already? And I have seen post #20.:)
 
Tranona said:
As already mentioned, Torqeedo is the only product that has managed to provide an acceptable compromise, but at a high cost.

Do not expect any significant change in the near future.
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I agree except that, as I said, I think we'll see other contenders in the Li-ion outboard market as prices fall. There are an awful lot of 2 - 4hp petrol outboards used exclusively for very short trips, and that's a market ripe for electrification. It's clear that there are fair few people willing to spend £1,000+ on this, and I suspect that at £500 there would be a awful lot more.

I rather fancy the idea of a lightweight Li-ion battery in my rigid tender, recharged when on tow through an umbilical from the mothership, but I suspect that's going to have to be home grown.

Shall we agree to continue disagreeing on hybrid auxiliaries?
 
sailorman said:
battery o/b are best used on a lake for fishing / trolling.
you need to learn ( imho) how to operate your petrol o/b, that is well suited to tidal waters & a far greater range than a battery one
i have a very reliable Tohatsu 3.3 2 T
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I remember a headmaster who sounded just like that.
 
Just a quicky.......I bought a second hand electric motor, from this very forum, and then used Amazon to buy a "golf caddy" battery, the type used on the trollies. The battery even came with a bag and carrying handle. The motor is made by Yamaha and pushes 2 men in an inflatable tender, complete with 2 kit bags, out to our boat some 100yds or so away and of course back at the end of the day. No issues at all so far (2 years) and all we do is wash it down with fresh water at the pontoon.
 
The Dogs Pollacks Brother said:
Just a quicky.......I bought a second hand electric motor, from this very forum, and then used Amazon to buy a "golf caddy" battery, the type used on the trollies. The battery even came with a bag and carrying handle. The motor is made by Yamaha and pushes 2 men in an inflatable tender, complete with 2 kit bags, out to our boat some 100yds or so away and of course back at the end of the day. No issues at all so far (2 years) and all we do is wash it down with fresh water at the pontoon.
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Nooo, that can't be right, The people who should be listened to on the the forum say they are useless.
 
Croak said:
Nooo, that can't be right, The people who should be listened to on the the forum say they are useless.
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Think most people would consider a 100 yard range twice a day pretty limiting.

Of course these motors will move a dinghy slowly over short distances, but they are only a substitute for an outboard over a very limited range of capabilities. If you accept the limitations that's fine for you, but would suspect most people want more.
 
JumbleDuck said:
I agree except that, as I said, I think we'll see other contenders in the Li-ion outboard market as prices fall. There are an awful lot of 2 - 4hp petrol outboards used exclusively for very short trips, and that's a market ripe for electrification. It's clear that there are fair few people willing to spend £1,000+ on this, and I suspect that at £500 there would be a awful lot more.

I rather fancy the idea of a lightweight Li-ion battery in my rigid tender, recharged when on tow through an umbilical from the mothership, but I suspect that's going to have to be home grown.

Shall we agree to continue disagreeing on hybrid auxiliaries?
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Not for tenders, but have a look at www.w1da.com for a new approach to electric propulsion. Boat was at Southampton but don't think it had the propulsion system. Hopefully it is more that CGI and words.
 
I bought a Bic 245 together with an electric o/b (Bison 40lb) together with a 110v Leisure on Ebay - very reasonable. Not used yet, the battery is hefty and I'm thinking of buying a much lighter battery for limited use as a tender - I'm following this thread with interest.
 
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