Electric outboard

[billyfish]

Anyone know if the Ultima outboard can be charged onboard ,12volt, any other comments welcome

 

[KompetentKrew]

I think they'd mention the availability of a 12v charger on the manufacturer's website if they offered one.

I believe Epropulsion &/or Torqeedo offer one, but they're a bit more expensive.

 

[billyfish]

I think they'd mention the availability of a 12v charger on the manufacturer's website if they offered one.

I believe Epropulsion &/or Torqeedo offer one, but they're a bit more expensive.

I couldn't see that

 

[KompetentKrew]

Epropulsion Spirit and Torqeedo 603 & 1103 - scroll down the page, just below the "add to basket" button it says "description - specification - accessories"; click on "accessories" and they both have a 12v charger.

 

[snowbird30ds]

I'd like to know how they all claim equivalent to 3hp yet 1000w works out to 1.34hp by my working out.

 

[dunedin]

I'd like to know how they all claim equivalent to 3hp yet 1000w works out to 1.34hp by my working out.

It’s partly pure marketing fib (as you have done the accurate power units conversion) and partly careful marketing ambiguous wording of “equivalent to” - as often don’t have petrol outboard on full throttle, so the low speed torque of the electric motor will accelerate quickly compared to a petrol outboard on part throttle. And also the torque means can use a different prop.
But what seems clear is that if need full power, eg to get up on the plane, the 1kW electric motor lacks the full power grunt of a 3hp.
At least one reputable electric outboard retailer admits the manufacturers’ claims are somewhat misleading.

 

[billyfish]

 

[Chiara’s slave]

I’ve got an e propulsion. And a 12v/solar combination charger. And the comments about torque and power are borne out in practice. It won‘t make you plane, but everything below that it does amazingly well. And it doesn’t smell, always starts, and is 100% female friendly.

 

[KompetentKrew]

I'd like to know how they all claim equivalent to 3hp yet 1000w works out to 1.34hp by my working out.

From previous threads:

Re the horsepower equivalent (specifically that word) statement, I'd prefer it if both manufacturers were clearer than they are. 1kW is indeed 1.3hp. But a 1kW electric motor has much more torque than a 1.3hp petrol motor, so - when fitted with the right sort of propeller - able to provide much more "shove". It won't have the top speed of a 3hp motor - it won't ever get a dinghy on the plane - but when a dinghy is in displacement mode (ie most of the time if you stick to harbour speed limits and/or have two or more people in it) I'd actually say the electric motor is more effective than a 3hp one. And certainly much more pleasant to use. The greater torque is why electric outboards, when designed to take advantage of their different characteristics relative to petrol, tend to turn larger propellers more slowly than petrol "equivalents".

and:

We try to avoid equations because they put a lot of people off reading, but maybe it is unavoidable. …. I agree making spurious claims isn't helpful but I don't think it is unreasonable to suggest that a 1kW electric outboard has quite a similar output to a 3hp petrol one, in terms of what the typical user wants and gets from it. But if you want to get a really lightly loaded dinghy on the plane it is not equal or equivalent. In most scenarios where the 3hp petrol can't plane (ie with more than one person aboard) the electric one will probably be better. Saying it's equal is wrong and if I've ever said that it was by accident of typing or not thinking enough beforehand. "Equivalent" (or even one would hesitate to suggest "roughly equal") is a less definitive term and if you need to get the point across reasonably quickly it is not unreasonable to use it. IMHO

I have trimmed the above quotes for brevity but you can read the full explanations by clicking on where it says "nestawayboats said ↑" above.

The second post I've quoted is particularly comprehensive and gives three different scenarios - IMO it's very reasonable and one should read it thoroughly before rehashing this argument.

It's a pointless debate because the "equivalency" is now out the box and can't be put back in again until petrol outboards and their HP are forgotten by the boating community. Or unless, I guess, it's banned by the trading descriptions authorities.

If Epropulsion and Torqeedo both offer a 1000W motor and one of the companies advertises it as "3HP equivalent" then the other must do the same otherwise they'll lose sales. Advertising it as a 1.34HP is a total non-starter, and would now be total suicide from a sales and marketing perspective. It's going to be very tiresome of this discussion needs to be rehashed every time electric outboards are mentioned.

 

[billyfish]

I know, all I asked is can it be charged on my boat...before I go and try them

 

[Chiara’s slave]

I know, all I asked is can it be charged on my boat...before I go and try them

I’d expect them to shout it from the rooftops if it could.

 

[billyfish]

Exactly

 

[Chiara’s slave]

Power wise, its the same spec as mine, no reason to think it would perform differently. The battery is 60% of the capacity. We could manage with that in our situation, it’s 800m from slipway to mooring, with a tidal current that’s not always in your favour. It will do at least 4 trips with the e propulsion.

 

[Tranona]

I'd like to know how they all claim equivalent to 3hp yet 1000w works out to 1.34hp by my working out.

it is simply because it is not the power source that moves the boat, but the propeller. So the meaningful measurement is thrust at the propeller, not potential HP at the flywheel. Electric motors are simply better at delivering usable power to the propeller at displacement speeds. Note how large the diameter of the propeller on an electric outboard is compared with the "equivalent" petrol motor.

I learned all this over 40 years ago while working for British Seagull when we were trying to convince regulators to use thrust as the comparative measure. Just like today's electric motors we were able to use the 1Kw output of our puny 1930s 2 stroke engine to produce thrust and power small dinghies at comparable speeds to 3hp outboards and our larger 1.5Kw engine to give performance equivalent to 5 or 6hp petrol engines on boats up to 20' or so.

Very simple - we started with the most efficient propeller type and turned it at the lowest shaft speeds through reduction boxes varying from 2:1 to 5:1 depending on the type of boat we were aiming at. Just look at any Seagull engine and you will see what large propellers they have compared with high speed engines of greater power - most of which is wasted and can't be turned into thrust.

 

[Chiara’s slave]

It’s easy to verify that, too. Find the pitch of your propellor. Multiply by the number of revs a minute at the shaft at max power rpm. Then by 60 to get the distance advanced in an hour. Make that into nautical miles, deduct say 15% for slip, and theres the speed your engine and prop are designed for. Usually that will be planing speed. If the motor doesn’t have the actual power to make your tender plane with your wife, a crew, the dog and the gear on board, the electric motor will be just as fast and 1/10 the hassle.

 

[snowbird30ds]

Thank you all for clearing up my query, I'm now more tempted with an e-propulsion spirit.
And apologies to OP for effectively hi-jacking the thread.

 

[ylop]

I looked briefly at options for charging on board for most makes the cost of a 12v charger you can get an inverter which whilst less efficient would provide the option for other uses too. It’s worth noting that none of the chargers are that fast, even the “fast chargers”. When you take that into account I started to wonder if a second battery (how much!!!) was a better option.

 

[Chiara’s slave]

I looked briefly at options for charging on board for most makes the cost of a 12v charger you can get an inverter which whilst less efficient would provide the option for other uses too. It’s worth noting that none of the chargers are that fast, even the “fast chargers”. When you take that into account I started to wonder if a second battery (how much!!!) was a better option.

We might not have bothered with a 12v charger, but the option to plug the charger in to a solar panel directly persuaded us.

 

[mattonthesea]

Our Torquedo battery charges at about 1%/hour off the domestic batteries. There's nothing clever about the 12v chargers you can buy; they are just connectors. All the clever stuff is done by the battery. Not really a problem for us as we don't feel the need to travel faster in the dinghy than we do in the boat . We generally use about 7% per day when at anchor.

Nest away contributed a lot of good stuff on a forum thread a few years ago until he was warned off. It might be worth a search for that for the comparisons. It was very objective.

 

[Chiara’s slave]

Seriously, 1% an hour?

I ask because that’s not the case with the e propulsion. The combined charger has a box of smarts of it’s own. The book says it can do 180w on solar, and from the design of the device, that has to be true of 12v, it uses the same power input cable to the charger.