Electric vs Petrol: Which Is Better?
I’m going to put it out there, I have a dog in this race…
We’ve used various petrol outboards over time. I’m a petrol head. I like thrashing cars, particularly those with large V8’s with tonnes of power and torque.
But, out on the water I’ve not been happy about petrol outboards for a long time.
- I hate the smell in the car when carrying it to and from the boat
- Temperamental starting even on my trusted Tohatsu 3.5hp four stroke
- Don’t ask about my 4hp 2 stroke
- Or my other 3.5 four stroke
- The noise
- Dear god the noise
There is a lot more to consider so I’ll take you through our thought processes and why we’re fully committed to the electric outboard route for all of our boats, why they suit what we do, why they might not suit what you do and if so, ways you can mitigate that if you are still interested.
A quick summary of some pro’s and cons for electric outboards in no order whatsoever:
|Ease of use
|Batteries are very expensive Change of mindset needed to "buying all of my fuel forever right now!"
|Unknown and / or limited range
|Reduces water pollution
|Limited range of power options for larger boats
|Reduces sound pollution
|Weight of batteries
|Reduces air pollution
|Helps your carbon footprint with zero emissions at point of use
|Reduced weight and better weight distribution
|Can save you money
|Electricity is cheaper than petrol
|Almost infinite range with solar panels and wind turbine
|Improving battery technology
So lets take these points and see what they really mean and what actually applies to you.
Ease Of Use
So you’ve had no winter maintenance, just put your battery on charge (possibly via solar) to make sure it is bang up full.
You turn up at the dock and drop the motor on the bracket – it’s nice and easy as the motor is lighter than the petrol outboard.
You put the battery onboard separately – having the system in two parts makes each part lighter and easier to handle (so I can let my wife do it. Hooray!)
Plug in your battery, turn on the motor, twist the throttle and reverse off the dock. Hmm that was easy.
You’d forgotten how good it is to not have to spin the motor around for reverse. Bloody awesome!
You partly turn around then reverse the throttle and silently glide off forwards making the most of the massive torque and low revs.
In peace and quiet!
Anyway, you are out for a couple of hours, everything feeling good and decide to use the shallow draft of the Adventure 600 to pull up on to the very shallow beach.
As you approach the beach you can simply reverse and coast up perfectly – no crashing in unable to get reverse thrust. Joy.
You enjoy your lunch and head back to base – edging onto the pontoon and the reverse and massive torque means your ability to manoeuvre is radically better.
So easy. No stress. No hassle. Just enjoying the sailing.
Thinking about it, you’re really missing
- the arsing about setting the throttle just so (you always forgot to lubricate the throttle on the petrol so it was sticky)
- getting the choke just right
- multiple pulls later “oh it caught”, rev it up and let it get warm (while your wife is getting cold)
- ok you’re ready, spin the engine 180 degrees to get into “reverse”, drop it into gear and have to think about turning the throttle the wrong way
- engine dies as you didn’t quite catch it right
- you’re now adrift as the lines were released as your wife couldn’t hear over the initial noise
- which swiftly died along with your ability to steer
- so, some frantic pulling on the starter handle and it’s back up and running, you clunk it gear and narrowly miss drifting into your mates boat next to you
- that is only there because he hadn’t winterised his petrol outboard properly so wont be out until next week as the b4stard wouldn’t start
- it’s ok, no stress, we’re happy, loving it in fact
- this is why we go sailing?!?!?!
This also ties up with the overall and ongoing costs below BUT this is also about massive convenience.
You finish your sail, coming back in you are enjoying being able to hear your wife telling you that next time you “had better go slower or else!” and revelling in the ease with which you can soak up the abuse.
A quick wash, pop it in the car (no stench, lovely!), no spilt petrol on the seat (awesome), pop it on the rack in the garage. Job done. Maintenance finished…
The new season rolls up and you don’t have to drive back and forth to your local workshop to find they’ve closed early again even though you said you were coming, then have annoying calls to find out they still haven’t done it but will “probably have it ready for the first race of the season” and seem impervious to the fact that they’ve had it for 4 months. Apparently that is your fault / problem – “take it however you like, no else will get it done quicker, it’s peak season now mate!”.
Instead, you just take it off the rack, drop it in the car and you are ready to go. Take the battery of charge and put it in the car.
That is it. Pretty tough. What have I forgotten?
No, that is it. Really.
No worrying about the crappy ethanol in the fuel gumming up your fuel filter and float bowl and having a layer of water in your tank ready to cause a(nother) fiasco.
Did you run the motor for long enough in clean water to fully clear out all of the cooling channels?
Where is my toolkit with spare spark plug and kit to remove the fuel pipe and drain water while out on the water?
Why didn’t you winterise it? Well you didn’t want to pay the workshop guys because they were so rude and useless again.
You were going to do it yourself.
Really do it this time.
Not just talk about it!
But you forgot again anyway and then in February thought “I’ve got plenty of time before the first sail”.
But you’re meant to be sailing tomorrow night and no way in hell that thing is starting.
Reduces Water Pollution
All petrol outboards create some mess in the water, from the exhaust venting through the water (we will be writing a separate article on this and will update a link to it from here), spilling fuel while refuelling on the water to the basic combusted gases being expelled via the exhaust and dissolving in the water.
Nitrogen, carbon monoxide, particulates and various harmful organic compounds are all vented out into the water. 4 strokes are approximately 10 times cleaner than 2 stroke engines but are far from angels themselves.
The IMO released a study in 2007 that showed that 1.12 billion metric tonnes of carbon dioxide are released into the oceans year.
That will not have improved since then.
This is something I find really unpleasant and was certainly
Reduces Sound Pollution
This is actually the biggie for us.
I used to love my old 2 stroke motorbikes. Awesome things. Tuned up Yammie FS1E, loads of off roaders, Suzuki RG500 all great fun.
But jeepers the crap that comes out of them!
But really it’s about the noise.
As a kid, it was great fun burning round the fields and mountains of Wales on your scrambler.
BUT, trying to come back in to land with heavy wind, sails and rigging flapping and slapping, it’s all getting a bit stressy and being unable to understand your crew (wife) who is shouting her lungs out 4 meters away is dreadful.
More stress between us getting in and out than anything we’ve ever had! Needed sorting, so electric all the way!
With the brushless motors immersed in the water, you barely know they are there and at low revs are effectively silent.
Stress gone. Happy wife. Happy life.
Reduce Air Pollution
2 strokes particularly emit a lot of particulates into the air, four strokes are better but not remotely good still.
Zip, zilch, nada, nix, zero.
You’ll be welcome at your lake long after the petrol outboards are banished.
Zero Emissions At Point Of Use
A potentially contentious one?
Oh, but the electricity is from burning coal at the power station!
The solar panels are created using fossil fuel and toxic chemicals
Two stroke motors were banned due to the vile and massive level of emissions (ignoring the sound nightmare) and as many cities are becoming unwelcoming to petrol and diesel vehicles, so more and more waterways and lakes are becoming electric only. I doubt it will be too long before your local marina starts charging a premium for fossil fuelled outboards are their use becomes more restricted / chargeable.
As mentioned previously above, you might be on a sustainable electric tariff – no coal there. We are and it blows the fossil fuel mains charging argument away. We also have a large solar array with battery system so barely use the grid anyway.
That argument is becoming less and less relevant I think?
You might also have a wind generator on your boat for topping up – again it is all taking away from wasting finite and toxic fossil fuels.
Reduced Weight* And Better Weight Distribution
The electric motors are very light, much lighter than the outboard.
As an example, the Haswing Protruar 5 (2.5kw max power) completely outclasses the Tohatsu 3.5hp for speed and responsiveness and weighs 14.5kg, while the Tohatsu with petrol weighs 19kg.
This is possibly not a huge thing for some boats, but on our Adventure 600 trimaran, we are reaching over the side AND back to mount it – saving nearly 5kg at arms length is very handy indeed!
The weight of the battery depends on which motor we are using exactly, but is circa 12kg for the LiFePo4 50Ah. This sits up front by the daggerboard in the cockpit so well out of the way and moves some weight forward.
The Adventure 600 is designed to be sailed nose down and is very sensitive to heavy weight hanging off a bracket at the back, so this is really helpful both in setting up / taking down as well as out on the water.
- * Yes more weight overall with electric BUT the weight distribution is much better making the boat far more efficient helping to keep the transom out of the water.
Can Save You Money
One interesting aspect that needs careful consideration is the concept that buying your battery is effectively buying all of your fuel forever up front, in one go.
How much fuel do you use? How often are you out in the boat and how long do you need the engine for?
Counterintuitively for us, we only use the motor on the Adventure 600 for a few minutes leaving the ramp while we hold into the wind, raise the sail then clatter off at a rate of knots. Coming back in again, a few minutes holding into wind, drop the sail and motor back in. Half an hour all in?
However, if you are using several gallons fuel a time (we used to use about half a cupful per trip) then with costs at around 170p litre (16/03/2022), this soon mounts up.
Recharging your battery via solar is essentially free – yes, I’m ignoring the capital cost of the panel, but a single cheap panel can have the battery ready for next weekend normally no problem.
Charging from the mains at home, trivial, a few pence depending on your battery size and state of discharge. Currently we pay 18p per kWh, and our 48v 30amp hour battery is 1.4kw so negligible.
This was not the driver for us but also the not calling in to the garage to top up half a gallon, spill it, get a smell in the car is a related factor.
The bigger aspect is more to do with the lack of servicing and winterising costs though. If you do not do this yourself and get the local workshop to do it, it is probably costing you £150 a year in re-commissioning and de-commissioning each year. That will buy your battery outright within a couple of year.
I do my own servicing but still had consumable spark plugs etc to replace.
Larger motors can potentially more readily show a long term cost saving:
Buy a £4k 15hp petrol outboard, spend £800 on petrol a year and £200 a year on servicing (minimum I think).
Instead buy an 11kw (15hp-20hp) electric motor plus batteries and only spend £200 a year on electricity.
The electric motor and batteries have paid for themselves within 5 years and fuel prices are only going to go up.
Electricity is Cheaper than Petrol
Wow. So petrol at 170p a litre, the previous Tohatsu 3.5hp would run for approx an hour at part throttle using approximately a litre, so £1.70.
Using our 48v 2.8kw Ez Outboard L03, we have way too much power and run it around 20% max throttle so would use perhaps 576 watts. Literally a few pence to recharge at the mains or “free” from a solar system.
Depending on your boat, solar panels directly on it can be really powerful. A houseboat potentially has space for a large amount of solar panels.
Almost Infinite Range With Solar Panels and Wind Turbines
What we find interesting is that the Adventure 600 really requires very little power to cruise along with the electric outboard.
We’ll be posting videos showing the speed/range expectations for different motors and batteries.
Essentially, with only mid hundreds of watts, we can cover a serious amount of ground and even if totally becalmed, we can easily get back in.
We’re putting in some small solar panels to boost the battery back up and will be trialling a WindLilly (when it finally arrives). Even a small amount of additional power wile out out sailing or while moored up over night will make a huge difference to range because we generally only need half an hour at low hundreds of watts to launch and retrieve.
Looking at this logically, if we can top up at 50-100w for several hours we are back completely full and if a sunny day we could potentially keep moving just under solar to at least some degree.
We don’t have much space for solar on Skippy the Adventure 600 trimaran, but when we launch our new RowSailer prototype later in 2022, we are designing and building it specifically to have a significant amount of flexible solar panels. However, being MUCH much lighter and only requiring a pretty small motor, we should end up with some impressive electric range potential.
If you really can’t be bothered to actually row it using the full sliding seat rowing station it comes with….
Or the pedal drive if that is your preference…
We’ll get testing hopefully later this year and post some results.
Improving Battery Technology
Battery technology is improving all time, with more power density, faster charge times, smaller size and reducing weight evolving all the time.
Our motors are basically battery agnostic – you are not going to be tied into a particular battery with a proprietary connector (apart from the Haswing Ultima series – but you can still use external batteries on that – article to follow).
I prefer the LiFePo4 chemistry which is extremely safe – having no issues with thermal runaway and able to deal with punctures.
This has a slight weight / volume penalty but is my preference.
You might prefer Lithium Ion because you already have some available?
Perhaps you might have a pile of Lead Acid batteries that have some decent life in them. Crack in and use them. You know they weigh a tonne but use them until they die and maximise your value from them before replacing them with whatever chemistry you prefer and is available at that point.
- Lithium Titanate Oxide can have a massive number of charge cycles – more even than LiFePo4 batteries
- Sodium may well replace Lithium in the near future – it is much cheaper as it is more abundant and not limited to politically dubious countries
- Solid state batteries
We will even be testing keeping our mini 800w petrol generator with us to act as a fail safe in case of some utterly random or bizarre battery failure – I’m really thinking of me being drunk and tipping it overboard somehow…
A petrol genny that can output some decent charge either directly to the battery or potentially straight to the motor will make for some interesting tests and understanding of efficiencies.
For some people, a petrol or diesel genny in conjunction with and electric motor (making a sort of hybrid system) could be very useful for much longer range but quieter ability to cover ground.
We will keep you posted!
The Elephant In The Room
Range, Range, Range!
The electric motor naysayer equivalent of Location, Location, Location!
Well, let’s think about this a bit more clearly and logically.
If we take a 1kw electric motor eg the Haswing Ultima which has max 1030w from 29.6V so a maximum draw of 35amps.
The battery is a 20.3Ah so at full tilt it will run for 35 minutes.
A spare battery weighs 5kg so can be thought of as similar to a spare can of petrol.
Total weight for the Ultima with spare is 21kg but with only 16kg hanging off the transom.
How often are you running flat out with your outboard for an hour or more?
I assume after that long you would be going to hospital to get your impending deafness investigated, but……
The biggest problem that we are aware of from petrol outboards as well, a huge increase in throttle does not result in a huge increase in speed.
Burning through your petrol or electricity much more quickly does not mean you will actually get where you want to go!
|Max Speed (km/h)
|Running Time (hh:mm)
This table is very interesting! To me anyway…
If I need to get back to base and have 10km to cover, am I bothered about covering that as quickly as possible?
An emergency perhaps? Hopefully I would call the RNLI and they will be out in their 25+ knot ribs, grab and take us back.
Under normal circumstances I would look at this scenario and think, ok, if I sit at half throttle it will take me just under two hours and I will still have plenty to spare.
If I need to speed up some as I get closer I will knowing I have plenty of leeway.
However, how often am I needing to motor for 10km?
You might argue well in significantly larger boats I may need to motor but then we would have a much larger battery bank, and a sizeable solar installation no doubt.
If we are only drawing 17-18 amps at half throttle, that is around 500 watts and we are making nice steady progress.
300w of solar panels feeding in possibly 200 watts passively to the battery is potentially adding 40% further range again.
However, for most smaller boats, the motor is used launching and retrieving and even a couple of smaller panels charging while you are can potentially completely top you back up before you get to your destination where you want to navigate into the harbour.
I think the elephant in the room should be thinking about hiding behind the curtains as this is not the massive issue that many people think it is!
Are you convinced?
Or perhaps even just a little bit interested?
I hope you are – if you’ve not tried it you may well be very surprised by how electric could work for you.
The main thing to understand is that this is potentially just a bit of change and change is very often very good and nothing to be scared about!
Instead, you just need to understand exactly what updates to your current ways of thinking and processes might be needed to maximise the gains you could get from going electric.
It is not all roses of course and simply may not be suitable for your needs at the moment.
It might take a little thought and effort but the rewards can be massive.
If you have a think about how it could work for you will be very different from thinking abut how it won’t work for you.
Certainly, since making the change to electric motors, we have never looked back and it has removed the biggest pain for us going sailing – noisy and unreliable launches and retrieval.
Drop us a line and see what motor and battery might suit you and we can see if we can arrange a suitable test for you.