Converting a small outboard to electric

[peterhull]

I have a trailer sailer and I only need 4hp outboard for close quarters manoeuvring. I am starting to wonder if converting this size of outboard to an electric one is feasible.

Has anyone got any experience of this. I had a look on UTube and there seems to be several ways of doing this. There appear to be conversion kits available. So e seem to favour 48 volt brushless motor with lithium batteries.
Welcome any thoughts on this.

 

[Pete7]

Wouldn't it be easier to buy one of the small electric outboard motors and just add a lithium battery, either DIY in a pelican case or a suitable electric bike battery.

Electric Outboard

 

[peterhull]

Thanks Pete7. Yes could be an option. There are some cheap ones on the market. I am not sure about the quality of the Bison. Seems incredibly cheap.

 

[Pete7]

Agreed, difficult to sort them out into any sort of quality rating but at least they are cheap enough.

 

[Tranona]

Thanks Pete7. Yes could be an option. There are some cheap ones on the market. I am not sure about the quality of the Bison. Seems incredibly cheap.

Don't know what size your boat is but a Bison is not really suitable - not powerful enough to be practical as an auxiliary for a boat that needs a 4hp. There is really no alternative to having a dedicated electric outboard such as a Torqeedo and that takes you into price territory with a reasonable battery bank that is far greater than a petrol outboard. The Torqeedo Cruise 2 is close to £3k.

The cheaper "Trolling" motors are only suitable for dinghies, and even then because most require a separate battery are only of limited appeal.

As ever is something looks "cheap" it is cheap and not a viable alternative -if it was (and these motors have been around for 40 years) everybody would be using them.

 

[Ningaloo]

I have an ePropulsion Spirit for my 2.6m aerodeck tender. It is a perfect solution for me, but it is less slightly powerful (in terms of max speed achieved) than a 3hp petrol engine.
If you have a 4hp, I think that you would be best using the Navy 6 from the ePropulsion range. I'm sure Torqueedo have an equivalent offering. As you will find, this solution is much more expensive than an ICE. All depends on your needs, how much peace an quiet means to you and what options you have for recharging the battery.

 

[Neeves]

I'd pondered slightly differently

I'd wondered about converting a dead petrol outboard to use as a hydro-generator. Simply using the prop and, ideally (long), shaft etc to connect to the head from a bladeless wind gen. I did not get any further than pondering as I have neither the dead O/B nor the bladeless wind gen (but these restrictions might disappear).

Jonathan

 

[KompetentKrew]

I have an ePropulsion Spirit for my 2.6m aerodeck tender. It is a perfect solution for me, but it is less slightly powerful (in terms of max speed achieved) than a 3hp petrol engine.
If you have a 4hp, I think that you would be best using the Navy 6 from the ePropulsion range. I'm sure Torqueedo have an equivalent offering. As you will find, this solution is much more expensive than an ICE. All depends on your needs, how much peace an quiet means to you and what options you have for recharging the battery.

There's a video on ePropulsion's YouTube of the Spirit being used with a Melges 24. I'm certainly no expert, but it looked quite suitable to me.

This French guy tried one for a couple of weeks with his mini transact and seemed to like it:

Most of the video is sailing, and the ePropulsion is less featured, but if you skip to the last 5 minutes he gives a summary. The video covers a period when he sails from La Rochelle (or somewhere near there) to Lorient and back, and also mentions stopping at Île d'Yeu, so he must've used the Spirit several times to motor in or out of port.

As per previous thread, the different qualities of petrol vs electric motors mean the HP equivalence is inexact. I would have thought that the extra torque would electric more suitable than petrol for marina manoeuvring - that you could apply a burst of speed or breaking more quickly - and also for heavier boats. You may recall there's discussion of this on Nestaway's website - "Where the Torqeedos excel is pushing surprisingly heavy loads (when the 3hp petrol wouldn’t get you on the plane anyway) at up-to-displacement speeds. They’re more than happy pushing a 9ft inflatable dinghy with 4 people in it at about 5 knots, for example."

Another video, by a different author, shows a Spirit pushing a 11m 8000kg traditional boat along, but it's not clear to me how slowly - he is getting 3,9knots with the wind and tide. The boat has a 90HP main diesel, but he takes tourists on seal-watching trips so wishes to use the Spirit when close to the animals.

 

[ridgy]

I have a bison 68 for my hunter f1 and it works well for parking. Less so on the open sea against wind and tide for which I have a 5hp outboard but on inland venues that prohibit such engines it is just the job.

 

[peterhull]

Thanks for everyone who contributed to this thread. Very interesting to hear of different solutions.
My Privateer 20 design weight is about 660 kg but I guess when loaded with gear is heavier.
4hp is very adequate , in fact I do wonder if less power would be ok for slow manoeuvring.

I don't need a winter project but got a bit fired up by using a small electric outboard to get me in and out of small slots like marina berths. Since I created the thread I have looked at more Information on this. It looks like the most expensive item are the batteries if Lithium ones are used for compactness or weight.

Some enterprising boaters have even created a small inboard version but that means a stern gland which is a potential leak below the waterline. On outboard you can remove, store and service it at home.
Anyway many thanks for your contributions I need to give this some more thought.

 

[peterhull]

I have a bison 68 for my hunter f1 and it works well for parking. Less so on the open sea against wind and tide for which I have a 5hp outboard but on inland venues that prohibit such engines it is just the job.

Thanks. Yes I do wonder about keeping a petrol outboard and trying out the cheap Bison. I am a bit wary of wasting money on something that is not very durable though.

 

[Tranona]

I have a bison 68 for my hunter f1 and it works well for parking. Less so on the open sea against wind and tide for which I have a 5hp outboard but on inland venues that prohibit such engines it is just the job.

That is the whole point - you can move big boats slowly in flat water with minimum HP - just lash a dinghy alongside with a 2hp outboard and you will be surprised at how well you can push the boat around.

However once you want a practical auxiliary for a trailer sailer you soon hit the limits of electrics - lack of power and limited range. Worst at the cheap end using motors originally designed as trolling motors (low speed, flat water, powered from the mother ship batteries). As you move up the price range things improve - the Torqeedo 1003 (big dinghy motors) are OK for light boats up to about 20', but as a serious alternative to a 4hp outboard the Cruise 2 will do the job, except you still have the range issue and the faff of recharging.

 

[Kelpie]

I got a secondhand Bison 68 last year, it was certainly worth what I paid for it but after a few months of using it several times a week it is starting to fall apart. One of the transom clamps has stripped, which means it's pretty much unusable. For occasional use it's certainly better than rowing, and the silence and ease of use are great. I've also never worried about anybody stealing it!
I've used it on three different dinghies, I'm not sure how it would cope with a bigger boat. In reality it's more of a substitute for a pair of oars than a petrol outboard.

 

[peterhull]

That is the whole point - you can move big boats slowly in flat water with minimum HP - just lash a dinghy alongside with a 2hp outboard and you will be surprised at how well you can push the boat around.

However once you want a practical auxiliary for a trailer sailer you soon hit the limits of electrics - lack of power and limited range. Worst at the cheap end using motors originally designed as trolling motors (low speed, flat water, powered from the mother ship batteries). As you move up the price range things improve - the Torqeedo 1003 (big dinghy motors) are OK for light boats up to about 20', but as a serious alternative to a 4hp outboard the Cruise 2 will do the job, except you still have the range issue and the faff of recharging.

Thanks , I have a sculling oar on the stern, always a belt and braces person me. Yet to be used. Not sure how practical that would be in a marina though when you want to get the stern in a tight space.

 

[peterhull]

Vevor supply a 48volt brushless 1800watt motor with control gear and twist grip for a go kart. The technology exists for E Scooters and electric bikes which could easily transfer to a DIY project using an existing outboard leg. Just needs time and patience. Could be done I am sure. It's the lithium batteries which make it expensive but the cost of the whole project could be similar to the Bison but a lot more durable. The motor draws 40 amps so it would need electronic gear and battery to match.

 

[ghostlymoron]

There's a video on ePropulsion's YouTube of the Spirit being used with a Melges 24. I'm certainly no expert, but it looked quite suitable to me.

This French guy tried one for a couple of weeks with his mini transact and seemed to like it:

Most of the video is sailing, and the ePropulsion is less featured, but if you skip to the last 5 minutes he gives a summary. The video covers a period when he sails from La Rochelle (or somewhere near there) to Lorient and back, and also mentions stopping at Île d'Yeu, so he must've used the Spirit several times to motor in or out of port.

As per previous thread, the different qualities of petrol vs electric motors mean the HP equivalence is inexact. I would have thought that the extra torque would electric more suitable than petrol for marina manoeuvring - that you could apply a burst of speed or breaking more quickly - and also for heavier boats. You may recall there's discussion of this on Nestaway's website - "Where the Torqeedos excel is pushing surprisingly heavy loads (when the 3hp petrol wouldn’t get you on the plane anyway) at up-to-displacement speeds. They’re more than happy pushing a 9ft inflatable dinghy with 4 people in it at about 5 knots, for example."

Another video, by a different author, shows a Spirit pushing a 11m 8000kg traditional boat along, but it's not clear to me how slowly - he is getting 3,9knots with the wind and tide. The boat has a 90HP main diesel, but he takes tourists on seal-watching trips so wishes to use the Spirit when close to the animals.

Bruno (the sailing Frenchman) particularly likes the recharging facility which means you wouldn't be tied to marinas for keeping the battery topped up. AFAIK, Torqueedos don't have this facility but you can bet your boots their working on it. Looks like you get I hour running for ten hours recharging which is great for someone like Bruno.

 

[peterhull]

Bruno (the sailing Frenchman) particularly likes the recharging facility which means you wouldn't be tied to marinas for keeping the battery topped up. AFAIK, Torqueedos don't have this facility but you can bet your boots their working on it. Looks like you get I hour running for ten hours recharging which is great for someone like Bruno.

Like the Evo pod even better, also uses hydrogeneration

 

[peterhull]

Like the Evo pod even better, also uses hydrogeneration

just got a quote for the smaller Evo pod over £2k for a 1 kw , the battery is about the same as the Evo pod they say the equivalent of 3hp , not sure how they work that out since 1 HP equals 746 watts doesn't it?

 

[KompetentKrew]

just got a quote for the smaller Evo pod over £2k for a 1 kw , the battery is about the same as the Evo pod they say the equivalent of 3hp , not sure how they work that out since 1 HP equals 746 watts doesn't it?

Previous discussion of this in this previous thread, starting at post 20 with some explanation on the following page.

 

[Boathook]

just got a quote for the smaller Evo pod over £2k for a 1 kw , the battery is about the same as the Evo pod they say the equivalent of 3hp , not sure how they work that out since 1 HP equals 746 watts doesn't it?

There has got to be another way to compare electric and petrol outboards as HP doesn't seem to fit to well. Maybe its a bit like comparing LED and incandescent light bulbs. They moved from watts to lumens. Personally I haven't a clue watt at present. Hopefully some minds greater than mine will have a sensible suggestion; possibly .....