Converting a small outboard to electric

[LONG_KEELER]

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 .....

It's all a bit confusing isn't it . As has been mentioned many times , range and power are the problem. Seems to work well for many folks on this forum for a taxi service to and from the mother ship .

There is further confusion as most electric vehicles are not electric vehicles at all. They are gas/coal/wind/nuclear/hydro/fossil vehicles converted to electricity. It does seem to help however if the emissions are diluted and moved from cities to less populated areas. It's also questionable if a large influx of electric vehicles could be catered for by our current power stations .

I think the best thing us sailors can do is slap on more sail and solar. Lots of our forward motion is going downhill . Was it John Goode who said that 1kt of tide is the same as a F4 wind ? so we use lots of natural tide propulsion .

 

[dunedin]

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 .....

Actually I suspect may be compared to power and torque in cars. The electric motor has a lot of low end torque, whereas the petrol engine needs to rev nearer to full revs to reach full torque. But provided properly matched with the right propellor for the application, a small outboard will generally rev well.
Hence in the real world tests of the outboards in things like a small tender, the 1kW electric outboard has proven to be slower than a 2.5hp petrol outboard at full throttle. So the ”1kw equates to 3hp” statement should be considered marketing speak, unless proven in independent real world tests.
Precise comparison depends on application and prop - but for small outboards perhaps a comparison of 1kW to 1.8-2.0hp might be as good a start point as any (compared to the strict 1kW to 1.34 hp)

 

[slawosz]

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 use 3.3 Mercury for my 1300 kg Achilles 24. It gives my more than enough power for local sailing. And its much lighter than 4 hp. With your yacht I would check 2 hp Tohatsu or equivalent. I am going to try Aspen fuel which does not decay with time.

 

[AntarcticPilot]

It's all a bit confusing isn't it . As has been mentioned many times , range and power are the problem. Seems to work well for many folks on this forum for a taxi service to and from the mother ship .

There is further confusion as most electric vehicles are not electric vehicles at all. They are gas/coal/wind/nuclear/hydro/fossil vehicles converted to electricity. It does seem to help however if the emissions are diluted and moved from cities to less populated areas. It's also questionable if a large influx of electric vehicles could be catered for by our current power stations .

I think the best thing us sailors can do is slap on more sail and solar. Lots of our forward motion is going downhill . Was it John Goode who said that 1kt of tide is the same as a F4 wind ? so we use lots of natural tide propulsion .

Actually, most of the time the majority of UK electricity is generated from renewable sources, and it's usually well over 50% from non-CO2 generating sources (i.e. including nuclear). See G. B. National Grid status

 

[LONG_KEELER]

Actually, most of the time the majority of UK electricity is generated from renewable sources, and it's usually well over 50% from non-CO2 generating sources (i.e. including nuclear). See G. B. National Grid status

Yes renewables , although highly variable, can be impressive at times. It does offer hope for the future, and we are fortunate to be an island race for many reasons.

If there is a major shift from fossil fuels driven cars to electricity used from the grid it is difficult to see where the extra power is going to be coming from though.

 

[syvictoria]

I am going to try Aspen fuel which does not decay with time.

Interesting, although somewhat expensive, even at current forecourt prices. Let us know how you get on!

 

[slawosz]

Interesting, although somewhat expensive, even at current forecourt prices. Let us know how you get on!

I think this season I burned like 5-8 liters. So the price here is negligible. Or - I could have Aspen as reserve and use normal fuel? I will definetely create a topic after I will test it.

 

[peterhull]

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.

Thanks for the feedback. It's interesting to know about other members experience. I am not really prepared to spend the sort of money necessary to buy a commercially available electric outboard, I like the idea of experimenting with a DIY one. There was an interesting article in PBO in 2018/19 about someone who did this but it requires a fair knowledge of electronic components and even some simple software programming

 

[peterhull]

Actually I suspect may be compared to power and torque in cars. The electric motor has a lot of low end torque, whereas the petrol engine needs to rev nearer to full revs to reach full torque. But provided properly matched with the right propellor for the application, a small outboard will generally rev well.
Hence in the real world tests of the outboards in things like a small tender, the 1kW electric outboard has proven to be slower than a 2.5hp petrol outboard at full throttle. So the ”1kw equates to 3hp” statement should be considered marketing speak, unless proven in independent real world tests.
Precise comparison depends on application and prop - but for small outboards perhaps a comparison of 1kW to 1.8-2.0hp might be as good a start point as any (compared to the strict 1kW to 1.34 hp)

Thanks yes I tend to agree with all your comments. Matching the torque and power to get the result you need is key.

 

[peterhull]

Actually, most of the time the majority of UK electricity is generated from renewable sources, and it's usually well over 50% from non-CO2 generating sources (i.e. including nuclear). See G. B. National Grid status

Thanks , my original post was a need for an outboard for close quarters manoeuvring and a low power electric outboard . I thought it would fit the bill and avoid and nasty fumes and noise in marinas.

 

[peterhull]

Yes renewables , although highly variable, can be impressive at times. It does offer hope for the future, and we are fortunate to be an island race for many reasons.

If there is a major shift from fossil fuels driven cars to electricity used from the grid it is difficult to see where the extra power is going to be coming from though.

Yes I tend to agree with you about grid demand but I think it is early days yet. There is work going on with hydrogen powered cars. The Grid may also get smarter and be able to use power from other countries when renewables are producing more power.

 

[slawosz]

Yes renewables , although highly variable, can be impressive at times. It does offer hope for the future, and we are fortunate to be an island race for many reasons.

If there is a major shift from fossil fuels driven cars to electricity used from the grid it is difficult to see where the extra power is going to be coming from though.

I believe that this problem will solve 'magically' itself. Like many before. I think electric cars did breakthrough like 3-4 years ago, when all makes started to plan and now sell electric only cars. With current revolution, probably there is lot of companies that are working on the problem. Also, the solar panels could be a solution, even in UK. I believe that goverment could be keen to give people grants to install them as it could be cheaper in long run.

 

[AntarcticPilot]

Yes I tend to agree with you about grid demand but I think it is early days yet. There is work going on with hydrogen powered cars. The Grid may also get smarter and be able to use power from other countries when renewables are producing more power.

In my work editing academic manuscripts, I have seen a lot of work on the general topic of integrating EVs into the Smart grid. It's on the way.

 

[AntarcticPilot]

I believe that this problem will solve 'magically' itself. Like many before. I think electric cars did breakthrough like 3-4 years ago, when all makes started to plan and now sell electric only cars. With current revolution, probably there is lot of companies that are working on the problem. Also, the solar panels could be a solution, even in UK. I believe that goverment could be keen to give people grants to install them as it could be cheaper in long run.

Domestic solar panels have long attracted government subsidies and a generous return on the electricity generated. In fact, it's less now than it was 10 years ago.

 

[peterhull]

Domestic solar panels have long attracted government subsidies and a generous return on the electricity generated. In fact, it's less now than it was 10 years ago.

Yes Fortunately we invested about £10 K 10 years ago and we have just broke even..It was a good deal at the time, tax free income and index linked.!! Unfortunately our backward Govt reduced the grants which severely reduced investment in solar power. With any new technology there needs to be a certain amount of ' pump priming' to encourage 1st movers.