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Cost of a "proper" electric boat/series hybrid


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Following various recent threads I've been looking into this seriously, to see what the real costs are compared to diesel or a parallel hybrid.

 

My starting assumption is that the target is to have a boat that can do pretty much everything that a diesel or parallel hybrid can do, including river transits and travel in the winter, and provide plenty of onboard power with a quiet generator as well as solar. Of course you can reduce costs by building your own, taking shortcuts like reducing engine or AC power or generator size or using smaller battery banks, but these are the numbers I came up with using what I'd call "proper" commercial-grade components to get an equivalent setup. They may come as a shock...

 

Motor/controller : 20kW, Bellmarine Drivemaster 20W EVO (£11500 including accessories) -- water-cooled direct drive, avoids whiny/fragile belts/motors

Batteries : 30kWh (50V 600Ah) LiFePO4, 2x BYB LVL 15.4 (£11000) -- "proper" big-boy batteries, included BMS which controls charging, no need for absorption

Generator : BetaGen 10 (£9000) -- 1500rpm for low noise and long life, keel cooled, simple and easily maintained

Solar : 6 x 380W panels (~2kW peak flat-mounted) + MPPT (£1200)

Inverter/charger : Victron Quattro 48/10000 (£3500) can accept full generator output and charge batteries at 140A (7kW) as well as provide 230Vac

Controller : Victron Cerbo GX + Touch50 (£1000), controls and monitors everything via CANbus (moter/controller, batteries, solar, inverter/charger, generator)

 

Total is about £37000 for the complete electrical/charging/propulsion system. Endurance at full power on a river with the generator running is about 3h so no problem. Batteries will recharge from 100% DOD (allowable given the BMS system) in about 4h. Allows more effective use of boat space, especially at the stern you can get an extra few feet "free".

 

Compared to this a parallel hybrid using flooded 2V 800Ah traction cells (with similar 230Vac capability but no generator) is about £27k, and a straight diesel with big alternators/TP and big LA batteries is about £17k. Both can use LA because the currents are lower (around 200A instead of 400A) but this means much longer charging times on top of the need to do equalisation -- using LiFePO4 instead adds about £7k to both.

 

So roughly speaking the parallel hybrid costs about £10k more than the diesel (both with LA batteries), the series hybrid (with LiFePO4, essential because of high currents) about another £10k on top of this. But this gives many advantages, not least no need for any absorption charging -- can charge up to 100% and discharge down to 0% (or what the BYB packs call 0%, which may not be...) at any time and keep them pretty much anywhere in between (yes I know about the lifetime effects, but discharge to 0% or long times below 20% are not likely to happen all the time).

 

Still an expensive luxury, but not that much extra on the price of a new boat, especially when you consider the cost of conventional diesel/parallel hybrids using LiFePO4.

 

I'm sure some people will object and say that this is overkill and you can build it cheaper yourself and nobody needs that much power, but then that's not a like-for-like comparison... 😉

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I'm not sure why but my boat has a 40HP diesel engine (about 30kW).

Previous discussions concluded that you need about 2kW on average for narrowboat propulsion so your battery is good for 15 hours if no other load. I think, however, you are going to use the majority of that capacity each day during winter, particularly if you plan to run a water source heat pump for your domestic heating. If you can store the waste heat from your genny you might not need a domestic hot water heater.

My concern would be the documented issue with LiFePO4 cells: they cannot be used or charged at or below 0 degrees C

 

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11 minutes ago, George and Dragon said:

My concern would be the documented issue with LiFePO4 cells: they cannot be used or charged at or below 0 degrees C

If it is below 0C, then the canal has frozen over and you aren't going anywhere anyway! Alternatively, moving the cells in to the occupied cabin, or including a small heater in an insulated battery compartment gets round this.

Jen

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For a new build boat sounds good.

However as a retro fit to an existing diesel boat my question would be how much pollution is produced building and running that kit versus how much pollution will my present system produce over the next 20 years.

I suspect that my present diesel system will be a lot less.

Edited by Loddon
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1 hour ago, Loddon said:

For a new build boat sounds good.

However as a retro fit to an existing diesel boat my question would be how much pollution is produced building and running that kit versus how much pollution will my present system produce over the next 20 years.

I suspect that my present diesel system will be a lot less.

You're almost certainly correct. Ripping out and replacing an existing [anything] very rarely makes sense if it's still working.

1 hour ago, Jen-in-Wellies said:

If it is below 0C, then the canal has frozen over and you aren't going anywhere anyway! Alternatively, moving the cells in to the occupied cabin, or including a small heater in an insulated battery compartment gets round this.

Jen

The BYD batteries specify operating temperature range down to -10C; sitting inside a boat in the water in the UK they'll never get this cold, even if the canal surface freezes over the water underneath doesn't go below 4C.

 

https://www.bimblesolar.com/BYD-LVL-15.4

Edited by IanD
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Like the OP we thought of hybrid drive for our new boat. His costings are much the same as we made a year ago. We would be on a river that often goes into strong stream conditions and I was concerned that series hybrid might not have the guts to push against it and if it did, how long the batteries would last. As we already cook electric that would be a further drain on the batteries, and whilst we could run the generator whilst cooking this would reduce the charge into the batteries. And then there was the question of mains generator as the OP has selected, or 48v one that would give a higher charge rate but still be affected by the power consumed when cooking.

 

We also looked at parallel hybrid but to get 20kw of electric motor meant using the Beta 75, a bit overkill on a 60 X 10, even in a river. And having read through the installation manual which shows forced air cooling of the battery bank, the cooling tank for the motor, and the complexity of the electrical system made me think, did I want to get into this if something goes wrong.

 

So we've decided an a Beta 60  with conventional drive and a Beta 10 generator. If it goes wrong I'm pretty sure I can get us going again.

 

Oh. And if is £15000 cheaper which will buy a lot of diesel.

 

 

Edited by pearley
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2 hours ago, George and Dragon said:

I'm not sure why but my boat has a 40HP diesel engine (about 30kW).

Previous discussions concluded that you need about 2kW on average for narrowboat propulsion so your battery is good for 15 hours if no other load. I think, however, you are going to use the majority of that capacity each day during winter, particularly if you plan to run a water source heat pump for your domestic heating. If you can store the waste heat from your genny you might not need a domestic hot water heater.

My concern would be the documented issue with LiFePO4 cells: they cannot be used or charged at or below 0 degrees C

 

Running a water source heat pump with CoP of 4 to heat the boat (are these available?) would consume about 1kW when it's running to put out the same heat as a 4kW Ebersplutter/Webasto/stove.

Edited by IanD
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26 minutes ago, pearley said:

Like the OP we thought of hybrid drive for our new boat. His costings are much the same as we made a year ago. We would be on a river that often goes into strong stream conditions and I was concerned that series hybrid might not have the guts to push against it and if it did, how long the batteries would last. As we already cook electric that would be a further drain on the batteries, and whilst we could run the generator whilst cooking this would reduce the charge into the batteries. And then there was the question of mains generator as the OP has selected, or 48v one that would give a higher charge rate but still be affected by the power consumed when cooking.

 

We also looked at parallel hybrid but to get 20kw of electric motor meant using the Beta 75, a bit overkill on a 60 X 10, even in a river. And having read through the installation manual which shows forced air cooling of the battery bank, the cooling tank for the motor, and the complexity of the electrical system made me think, did I want to get into this if something goes wrong.

 

So we've decided an a Beta 60  with conventional drive and a Beta 10 generator. If it goes wrong I'm pretty sure I can get us going again.

 

Oh. And if is £15000 cheaper which will buy a log of diesel.

 

 

20kW is still more than some people are saying is "OK" for series hybrids (Finesse/Shine are 10kW IIRC which I don't think is enough) -- it's not as much as is usually recommended for diesel engines but this is output at the prop and there are no gearbox/alternator losses, 1kW per ton at the prop is what is normally recommended for displacement boats and a typical narrowboat (up to 60 foot?) is 20 tons or less. Anything above 20kW for a single prop gets *really* expensive (makes the Bellmarine look cheap...), can't be done from 48V which is the highest standard inverter/charger voltage, and everything needs treating as HV for safety which is a big pain for installation and testing.

 

The reason for a 230Vac generator instead of a 48Vdc one is that they're much more widely available, and on a boat which relies on AC power (fridge/freezer etc) you have some AC redundancy while you get a dead generator or inverter fixed. It also means the battery charging can be completely controlled by the master BMS in the battery packs (via the Quattro as a slave) to guarantee both protection and lifetime, this is much more difficult if a DC generator connects directly to the batteries.

 

A normal diesel has no drive if the diesel fails, a series hybrid has no drive if the motor/controller fails, so there's a single point of failure in both cases. The parallel hybrid is the winner here, you have two sources of propulsion -- OTOH you only have one source of 230Vac (the inverter). Depends which you think is worse, being unable to move or having no mains power and a freezer full of rotting food... 😉

 

Like I said, cost is not the reason for doing this, silent cruising and (maybe) future-proofing (diesel-free propulsion) for when charging stations appear is.

Edited by IanD
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If the objective is to reduce greenhouse gasses and so on - and that is a very good and necessary aim, then we all need accurate and easily accessible figures  comparing diesel to electric generating and storage. Obviously it is not just the wicked diesel fuel but as Loddon says making and running all the electrical gear might be much more damaging. I suspect it probably is. Remember when hybrid cars were going to save the world? A ton of batteries and electric motors AND a petrol engine. Hopeless. I expect there are figures but they are probably buried deep in scientific papers. Give us some figures! 

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17 minutes ago, Bee said:

If the objective is to reduce greenhouse gasses and so on - and that is a very good and necessary aim, then we all need accurate and easily accessible figures  comparing diesel to electric generating and storage. Obviously it is not just the wicked diesel fuel but as Loddon says making and running all the electrical gear might be much more damaging. I suspect it probably is. Remember when hybrid cars were going to save the world? A ton of batteries and electric motors AND a petrol engine. Hopeless. I expect there are figures but they are probably buried deep in scientific papers. Give us some figures! 

The only thing that will help with this are canalside charging stations, preferably using green energy, and minimising energy consumption. No solution is perfect, the question is whether it's better than the existing one. Don't forget that all the canal boats in the UK put together contribute 1000x~10000x less CO2 than all the cars do, so you could also say that UK-wide CO2 reduction isn't really a strong reason to go hybrid on a boat...

 

Electric cars (not hybrid tax fiddlers) are a different matter; cars generate a *lot* of CO2, and even if the energy comes from fossil fuels the "well-to-wheel" efficiency is about double that of ICE (so half the CO2 emissions). If the energy is green (solar/wind) the situation is obviously much better still. The numbers are out there, go and look, Google is your friend 😉

Edited by IanD
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A further advantage of the series solution is you can mount the generator anywhere, you can also use the generator cooling to provide space heating whilst it is running. I would be concerned about using water source heat pump because if every boat did it the surrounding canal/marina would soon freeze over.

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21 minutes ago, Detling said:

A further advantage of the series solution is you can mount the generator anywhere, you can also use the generator cooling to provide space heating whilst it is running. I would be concerned about using water source heat pump because if every boat did it the surrounding canal/marina would soon freeze over.

Very unlikely to cause a freezing problem -- a 4kW heat pump would cool 1kg of water by roughly 1C per second, and there's an *awful* lot of water in the canals...

 

Agreed about the generator -- my plan was to put it (and fuel tank/silencer/Ebersplutter) in the bows under a short tug deck. All the noise and exhaust fumes as far away from.the steerer as possible...

Edited by IanD
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1 hour ago, IanD said:

Electric cars (not hybrid tax fiddlers) are a different matter; cars generate a *lot* of CO2, and even if the energy comes from fossil fuels the "well-to-wheel" efficiency is about double that of ICE (so half the CO2 emissions). If the energy is green (solar/wind) the situation is obviously much better still. The numbers are out there, go and look, Google is your friend

About 10 tons of CO2 to make an ICE car and 15tons to make an electric car (i have seen figures as low as 13 and as high as 17 so have picked the midway point) that equates to about 40,000km before the electric vehicle becomes greener and that assumes all the electric is 100% renewable.

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11 minutes ago, Loddon said:

About 10 tons of CO2 to make an ICE car and 15tons to make an electric car (i have seen figures as low as 13 and as high as 17 so have picked the midway point) that equates to about 40,000km before the electric vehicle becomes greener and that assumes all the electric is 100% renewable.

The article quoted earlier (from a study funded by ICE manufacturers so may not be unbiased) had the CO2 difference at manufacture as 10 tons and the CO2 break-even mileage as 50k miles -- not forgetting this was for a big heavy Volvo, not a small city car.

 

None of which changes the conclusion that even in the worst case (power from fossil fuels) the lifetime CO2 emissions of BEV are much lower (less than half) than ICE. If the numbers are closer to yours and/or the power is renewable or the BEV lifetime is longer (all likely) the difference is even bigger.

Edited by IanD
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1 hour ago, IanD said:

20kW is still more than some people are saying is "OK" for series hybrids (Finesse/Shine are 10kW IIRC which I don't think is enough) -- it's not as much as is usually recommended for diesel engines but this is output at the prop and there are no gearbox/alternator losses, 1kW per ton at the prop is what is normally recommended for displacement boats and a typical narrowboat (up to 60 foot?) is 20 tons or less. Anything above 20kW for a single prop gets *really* expensive (makes the Bellmarine look cheap...), can't be done from 48V which is the highest standard inverter/charger voltage, and everything needs treating as HV for safety which is a big pain for installation and testing.

 

The reason for a 230Vac generator instead of a 48Vdc one is that they're much more widely available, and on a boat which relies on AC power (fridge/freezer etc) you have some AC redundancy while you get a dead generator or inverter fixed. It also means the battery charging can be completely controlled by the master BMS in the battery packs (via the Quattro as a slave) to guarantee both protection and lifetime, this is much more difficult if a DC generator connects directly to the batteries.

 

A normal diesel has no drive if the diesel fails, a series hybrid has no drive if the motor/controller fails, so there's a single point of failure in both cases. The parallel hybrid is the winner here, you have two sources of propulsion -- OTOH you only have one source of 230Vac (the inverter). Depends which you think is worse, being unable to move or having no mains power and a freezer full of rotting food... 😉

 

Like I said, cost is not the reason for doing this, silent cruising and (maybe) future-proofing (diesel-free propulsion) for when charging stations appear is.

Our original quote from Fischer Panda with a 20kw Bellmarine motor, 1000 amp/hr of lead carbon batteries and a 48 volt generator plus 7 kw of Mastervolt inverter was £48000. After demurring a bit it was reduced to £39000 with a 15kw motor and 800 amp/hr of LC.

 

The argument between 48volt gennie and 230 volt was never resolved. Academic now as new boat is in build, although not as much in build as we hoped due to you all know what. 

Edited by pearley
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19 minutes ago, pearley said:

Our original quote from Fischer Panda with a 20kw Bellmarine motor, 1000 amp/he of lead carbon batteries and a 48 volt generator plus 7 kw of Mastervolt inverter was £48000. After demurring bit was reduced to £39000 with a 15kw motor and 800 amp/hr of LC.

 

The argument between 48volt gennie and 230 volt was never resolved. Academic now as new boat is in build, although not as much in build as we hoped due to you all know what. 

Fischer-Panda are very expensive for generators (especially 48V) which have some reputation for being unreliable, are higher speed so need more maintenance, and are not really designed for keel cooling, and for high powers their inverters are more expensive than Victron and need paralleling up.

 

Lead carbon batteries cost more than traction cells but less than LiFePO4, are better than traction for partial SoC operation and absorption but not as good as LiFePO4, and are as big and heavy as traction cells -- LA weigh about 3x as much and need a lot more space. It seems to me that if you want the lowest cost for a big bank (e.g. parallel hybrid) 2V traction cells are the right option, if you want a serial hybrid without long charging times and can afford them then LiFePO4 is the right option. Lead-carbon are the in-between solution, not as cheap as traction cells and without the advantages of LiFePO4.

 

Edited by IanD
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43 minutes ago, IanD said:

Fischer-Panda are very expensive for generators (especially 48V) which have some reputation for being unreliable, are higher speed so need more maintenance, and are not really designed for keel cooling, and for high powers their inverters are more expensive than Victron and need paralleling up.

 

Lead carbon batteries cost more than traction cells but less than LiFePO4, are better than traction for partial SoC operation and absorption but not as good as LiFePO4, and are as big and heavy as traction cells -- LA weigh about 3x as much and need a lot more space. It seems to me that if you want the lowest cost for a big bank (e.g. parallel hybrid) 2V traction cells are the right option, if you want a serial hybrid without long charging times and can afford them then LiFePO4 is the right option. Lead-carbon are the in-between solution, not as cheap as traction cells and without the advantages of LiFePO4.

 

Thanks Ian. I did know all that but the OP was talking about a packaged deal so my post needs to be read in that context.

 

The problem at present is that unless you buy a packaged system if something goes wrong then if you have sourced bits from several suppliers then if something goes wrong everyone will blame everyone else.

 

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13 hours ago, pearley said:

Thanks Ian. I did know all that but the OP was talking about a packaged deal so my post needs to be read in that context.

 

The problem at present is that unless you buy a packaged system if something goes wrong then if you have sourced bits from several suppliers then if something goes wrong everyone will blame everyone else.

 

Agreed, but the problem with a packaged deal is often that some of the parts of it are more expensive or not as good or both.

 

Support of complete marine electrical systems (e.g. by Victron) is getting better as they realise that they can't supply everything that people want, so they need to be able to integrate gear from outside using CANbus -- this is largely driven by the yachting market which is much bigger (and richer!) than the narrowboat one and where people often want a lot more electrical gear, and also where a lot of electric drives are now being installed.

 

The BYB LVL batteries are a good example, the BMS in these these takes over charging control and battery protection from the Quattro and also provides all the diagnostic information (including individual cell voltages, temperature and SoC), and Victron have tested it and certify that it all works together.

 

The Cerbo GX is designed for exactly this purpose, there's a growing list of third-party kit that has been tested with it and is known to work, practically anything CANbus-based can be plugged in like alarms, level sensors, MPPT controllers, generators, battery monitors, alternator controllers and so on. I would expect electric drives like Bellmarine to either already be on this list or be added to it as more demand appears, again driven by the yachting market.

 

Technology (urghh, nasty nasty modern thing, make it go away...) is moving forwards rapidly and making these kinds of setups a lot cheaper and easier than only a couple of years ago... 😉

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For anyone still following, there's now an off-the-shelf (with UK support) electric drive solution for less than half the price of the Drivemaster (which is actually £12500 inc. throttle/display/cooling/contactor)

 

https://www.energy-solutions.co.uk/products/waterworld

 

Same output (15kW continuous/20kW peak), air-cooled instead of water-cooled -- so needs ventilation, but also doesn't need a keel cooler installing. Cost includes everything for the drive system, obviously batteries/inverter/charger/generator/solar are still on top of this. Either way, the cost for systems like this is dropping and hopefully will continue to do so.

 

Total cost for entire system including 30kWh of LiFePO4, 10kVa generator, 10kW Quattro, solar, and all other hardware (including house batteries) is now about £35k (with all the bits and pieces I didn't include before), compared to about £30k for a parallel hybrid and £20k for a "heavy-electric" diesel (without a generator) both with lead-acid batteries.

waterworld_wiring.PNG

Edited by IanD
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On 29/11/2020 at 15:47, George and Dragon said:

My concern would be the documented issue with LiFePO4 cells: they cannot be used or charged at or below 0 degrees C

Incorrect. They can be discharged below 0°C.

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I still think that a pod motor mounted in the rudder and leave the existing diesel in place is the way to go. 

 

Karvin 6800 looks good. About £7k for the pod and controls. 

 

Add to that some LTO batteries and a mains charger plus solar and you get a Secondary Propulsion electric system. 

 

Wouldn't it be nice to go along on diesel when you need the range then seamlessly switch across to electric for quite cruising and close quarter maneouvering..

 

At the end of the day the times when you need to do a lot of maneouvering tend to be when the boat is moving slowly so a vectored thrust and electric drive would be a very very nice thing to have. 

 

 

I think a folding prop would be worthwhile so that during diesel use there would not be too much resistance built into the rudder. 

 

You keep your original rudder and get a custom one made with the pod in it. That way you can put everything back to how it was if it turns out to be a nuisance.

 

 

48v charging alternator mounted on the diesel driveline perhaps on the prop shaft with extra plummer blocks for the side loading. That means that when using the diesel, which would be used when a bit of extra power is required, you would be using it as efficiently as possible with a variable load charging system. 

 

 

Edited by magnetman
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2 hours ago, magnetman said:

I still think that a pod motor mounted in the rudder and leave the existing diesel in place is the way to go. 

 

 

 

 

I think a folding prop would be worthwhile so that during diesel use there would not be too much resistance built into the rudder. 

 

 

A folding prop on a canal????

...er No!

It would need its own weed hatch. 

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