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Hybridising engines


OCM

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12 minutes ago, MtB said:

 

Quite. I don't think basic engineering limitations will allow a narrowboat to rely wholly on solar for daily locomotion.

 

Occasional, yes. One day cruising, five days charging seems more viable for a narrowboat, especially one with perhaps only 25ft x 4ft of spare roof space.

 

 

 

 

Scope for improvement lies in solar panel efficiency, I suspect. Current technology harvests barely 10% of the energy landing on a solar panel. If we can find a way to ramp this up to harvest say 50%, everything changes.

I'd agree with your estimate given that little space, I'm assuming 6 full-size panels (2.2kW peak) which need 38' of roof length -- OK on a boat designed for this, difficult to add on later. Average summer yield should be about 7kWh/day, more on a good day, less on a bad one.

 

Current rigid mono panels are just over 20% efficiency, limited by physics given the materials used (silicon). Multi-layer panels in the lab are getting towards 50% but are extremely expensive  (100X more? 1000x more?) and can't be scaled up to the production volumes needed to get cost down because they use either exotic elements or manufacturing techniques. There may be ways to squeeze a few more percent out of low-cost panels, we'll have to see what makes it to the market, but getting past 25% is going to be very difficult -- sorry, that's physics.

 

https://www.technologyreview.com/2021/06/29/1027451/perovskite-solar-panels-hype-commercial-debut/

Edited by IanD
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Thanks for the replies, all very helpful. This morning I rang Beta Marine. They tell me there is something that can reduce emissions, but the Beta 43, approx £8K, cannot be hybridised. They also told me that a new engine hybridised (Greenline I imagine) would cost £28K, but with the battery set up etc, would need to be fitted into a new boat. So it looks like utilising solar panels and so on.

Things can change very quickly though, just look at the diesel car market, overnight just dropped like a hot potato.

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45 minutes ago, MtB said:

Do tell us more! Are these narrow boats?

Yes this is a narrow boat.

A lot depends on the efficient of the motor. I am using 8 pole motors with 3-phase electricity   

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2 hours ago, Keith M said:

Yes this is a narrow boat.

A lot depends on the efficient of the motor. I am using 8 pole motors with 3-phase electricity   

Good PMAC motors like Engiro are about 96% efficient under actual operating conditions used in a boat, and the controllers are similar, so about 90% overall. Older brushed DC motors like Lynch quote 90% efficiency but when you look into the actual curves they're a few percent less than this, and also the controllers are less efficient (older technology), so overall efficiency is closer to 80%.

 

So the motor has an effect (about 10%), but not a big one.

 

Typical power consumed when cruising on a normal canal is about 3kW/4hp; many sources agree on this figure including Lynch, Hybrid Marine, Waterworld, Finesse, comparison with diesel boats, and the Vicprop calculator. There have been various claims of lower figures than this but the only way to believe them is if they're travelling more slowly than normal -- by which I mean the speed that most boats seem to travel at, including all the ones I've driven over the years where typical cruising rpm in a Beta 43 is 1400, which is 4hp at the prop -- gentle wake at bows and stern, nowhere near a breaking wash. A similar calculation when passing moored boats (at typically 1000rpm) gives around 1kW.

 

In a typical full day, if you spend 4 hours cruising, 2 hours passing boats, and 2 hours in locks the total energy consumed is 14kWh -- different cruising patterns will give different numbers, but this is a good guesstimate from my experience. This has to come from somewhere, and a big solar setup on a narrowboat (6 full size 380W panels) will yield about 7kWh average in summer according to various (realistic) solar power estimators -- which either means you can only travel 50% of the time on average in summer, or the other 50% (7kWh) has to come from a generator or plugging in (where?). Most hybrid boats use a Quattro 48/10000 which can charge batteries at 140A (7kW), so this means running the generator for an average of one hour per day if travelling all day every day.

 

All these numbers are realistic not optimistic and are backed up by various reports from actual users as well as figures from hybrid boat suppliers -- except for a couple of super-optimistic ones who I won't name...

 

Anyone claiming they don't need to use a generator on an "electric" narrowboat is either using some other type of physics, or pootles along very slowly holding people up, or doesn't travel very much in a day, or only travels where there happen to be marinas who have free plug-in mooring spaces overnight. All fine if that's what they want to do, but it's not how many people (including most hire boaters?) travel on the canals...

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6 minutes ago, IanD said:

Typical power consumed when cruising on a normal canal is about 3kW/4hp

I have to dis-agree with your figures typical with the narrow boats which I have been involved with no more than / 1.5 Kwatts roughly a third of your figures. With the GPS on board display around 3.5 miles per hour

Cursing the tidal Thames around 2.5 Kwatts against the tide part of the way. 

Edited by Keith M
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2 hours ago, OCM said:

Thanks for the replies, all very helpful. This morning I rang Beta Marine. They tell me there is something that can reduce emissions, but the Beta 43, approx £8K, cannot be hybridised. They also told me that a new engine hybridised (Greenline I imagine) would cost £28K, but with the battery set up etc, would need to be fitted into a new boat. So it looks like utilising solar panels and so on.

Things can change very quickly though, just look at the diesel car market, overnight just dropped like a hot potato.

 

The Beta hybrid is based on a Beta Greenline 43 (standard narrowboat fitting) but with the addition of the electric drive, dual 24V alternators, and control box -- it could be retrofitted but the labour (and hassle) involved means it would probably be cheaper to buy a ready-built new hybrid and sell the old Beta 43. The standard hybridmarine setup uses a massive 2V traction cell battery bank which is very difficult to fit into an existing boat; lithium cells are easier to fit in and need less generator running time but are even more expensive at present.

 

Of course if you remove the existing Beta 43 and install a series hybrid you still have to find somewhere to fit the batteries and -- often more difficult -- the generator, the motor and solar are the easy bit. Most marine gennies are too tall to fit on top of the swim, and there often isn't enough room to sit them on the baseplate where the diesel was once the electric motor is in.

 

Even if battery costs gradually come down (which is happening) generator costs (around £10k installed for a cocooned marine diesel) are not going to suddenly drop overnight though... 😞

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5 hours ago, pete.i said:

I do not know why everyone is bothering with hybridisation or Telsa or anything else that purports to save the planet. It's either doomed or it isn't no matter what paltry contributions we make. Big businesses are not going to stop shipping your iphones and all the other tech we use in great big heavy fuel oil powered ships belching out massive amounts of pollution. Nor are they going to stop using aircraft also belching out massive pollution in those pretty vapour trials everybody goes "OOOOOHHHHH" at. And that is not taking into consideration the vehicles on the roads or the industry or all the people who want to fly off to "exotic" locations around the world.

 

Some of the ships on our oceans at the moment and aircraft in the skys....... Think about it.

ships.jpg

flight.jpg

27% of ships delivered this year didnt use heavy oil things are changing consult splash 24/7 shipping website

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12 minutes ago, Keith M said:

I have to dis-agree with your figures typical with the narrow boats which I have been involved with no more than / 1.5 Kwatts roughly a third of your figures. With the GPS on board display around 3.5 miles per hour

Cursing the tidal Thames around 2.5 Kwatts against the tide part of the way. 

At what speed and on what canal?

 

(BTW 1.5kW is half of 3kW, not a third)

 

If on a deep canal up North like Peter, that's not typical for the UK canals. The Vicprop calculator -- based on lots of boat experience, and theory -- says 1.5kW/2hp will give 3kts which is 3.5mph in deep water, which agrees with your number -- this would be about 1100rpm on a Beta 43. In shallow canals people use more power to travel more slowly, hence the 3kW figure (1400rpm on a Beta 43). If you travel more slowly than this at fewer rpm, you will of course use less energy.

 

You can of course disagree with the figures I gave, but they're based on reports from various users and companies who build hybrids, as well as calculations and diesel boat experience -- are you saying they're all wrong and you're right? Or do you just go more slowly than normal, or only in deep water? Something doesn't add up...

Edited by IanD
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5 hours ago, Up-Side-Down said:

I understand that Hybrid Marine are no longer keen to be involved with retrofit parallel hybrid systems. As has been said, the way to go is to a serial hybrid system so junk the engine (you'll get a good price for it) and replace it with an electric motor. This is something I (amongst quite a few others) am looking at and at Crick it was interesting to see the choice, and to price up the exercise. I reckon  £20,000 would be a realistic figure for a basic conversion, from which you can deduct the value of your existing diesel.

 

As a member of the IWA Sustainable Boating Group (albeit with responsibility for HVO) the best advice I've obtained from my 'electric colleagues' is to not buy the whole package from one manufacturer. I'm strongly advised to have the confidence to mix and match with the possibility of saving up to a third on the total price. I'm assured that it's not rocket science and that a half decent marine electrician can specify and fit the right combination of kit.

 

You can certainly spend another £10,000 if you want to go down the lithium route but if you look around at the current parc of electric narrowboats, by far and away the majority them have chosen the half way house of lead carbon batteries for a whole raft of good reasons.

Lithiums are always the best route to go, secondhand packs are available cheaply enough in 48 volts configurations and will outlast the lead carbon batteries by a long way

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1 minute ago, IanD said:

At what speed and on what canal?

 

(BTW 1.5kW is half of 3kW, not a third)

 

If on a deep canal up North like Peter, that's not typical for the UK canals. The Vicprop calculator -- based on lots of boat experience, and theory -- says 1.5kW/2hp will give 3kts which is 3.5mph in deep water, which agrees with your number.

 

You can of course disagree with the figures I gave, but they're based on reports from various users and companies who build hybrids, as well as calculations and diesel boat experience -- are you saying they're all wrong and you're right?

I will try answer questions  1.0 kwatts is a third please read and reproduce all of sentence not just the bit which helps you out. 
The figures were obtained over a number of years and now nearly 2000 miles cruised.
I did attend Crick and did not hear the figures you are quoting more than one supply was using similar figures to which have been produced over a number of years and many craft built 

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3 minutes ago, peterboat said:

Lithiums are always the best route to go, secondhand packs are available cheaply enough in 48 volts configurations and will outlast the lead carbon batteries by a long way

For DIY like you did secondhand is obviously cheaper -- and if anything goes wrong, it's your problem.

 

Most commercial suppliers are understandably reluctant to use secondhand cells of unknown provenance such as those extracted from written-off cars, because it's very difficult to guarantee that they're not damaged, and if they are the consequences can be nasty -- especially since most are lithium-cobalt not LiFePO4 and can go wrong much more spectacularly even with sophisticated BMS systems which have been thoroughly tested by the car manufacturers.

 

LiFePO4 is safer for DIY, but most secondhand packs are not LiFePO4...

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@Keith M I wonder if you give us a few more details about your boat, ie how long, displacement, draught.  The figures you quote are way below what most of us assume a typical narrowboat might need, so I wonder if you have a particularly light boat, or if there is something else about it that makes it much more efficient through the water.

 

You are making some pretty groundbreaking claims which would completely change my views of electric power on narrowboats, and probably most folk on this forum.  It isn't surprising if we are a little sceptical. 

 

 

 

 

 

 

Edited by Neil2
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16 minutes ago, Keith M said:

I will try answer questions  1.0 kwatts is a third please read and reproduce all of sentence not just the bit which helps you out. 
The figures were obtained over a number of years and now nearly 2000 miles cruised.
I did attend Crick and did not hear the figures you are quoting more than one supply was using similar figures to which have been produced over a number of years and many craft built 

You're the one who said 1.5kW, I quoted you directly...

 

Yes several people including you (e.g. Shine) have claimed 1kW, and if you travel slowly I'm sure that is possible -- especially if it's an average including passing moored boats and in locks. My 14kWh/8hr day is 1.75kW average, which is not far off your 1.5kW -- and it only takes more moored boats or locks to pull this down further.

 

I do not believe that 1kW (or 1.5kW) is correct for "normal" cruising on a typical narrow UK canal, unless you travel more slowly than normal -- "normal" meaning most of the boats I see on the canals, when not going slowly past moored boats or in locks. This figure doesn't stack up with either theory or rpm on a diesel engine, for a large number of boats that I've steered over the years.

 

Going by my diesel experience, many of the boats I see on the canals, other people and suppliers who are less evangelical about electric boats (and the recent Ortomarine comparative test), I prefer to use a higher figure. But the average including moored boats and locks will be lower than 3kW, as I keep saying but you seem to keep ignoring...

 

When I've seen lower figures quoted and actually dug into them, they've often been average over a long journey -- which as I keep saying, depends on how fast you go and what the canal is like.

Edited by IanD
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1 minute ago, Neil2 said:

@Keith M I wonder if you give us a few more details about your boat, ie how long, displacement, draught.  The figures you quote are way below what most of us assume a typical narrowboat might need, so I wonder if you have a particularly light boat, or id there is something else about it that makes it much more efficient through the water.

 

You are making some pretty groundbreaking claims which would completely change my views of electric power on narrowboats, and probably most folk on this forum.  It isn't surprising if we are a little sceptical. 

 

 

 

 

 

 

It is standard NB built by one of the many fabricators within the UK.

As to weight most have been around 15+ tons.

It is down to design and care of installation, Using correct cable and CSA of cables. and other design features.

I one builder at Crick was stating only around 3 / 4 hours of cursing before recharging and that was Lithums.

 

 

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3 minutes ago, IanD said:

You're the one who said 1.5kW, I quoted you directly...

I have just looked at my post and it did say 1.0 / 1.5 kwatts.

What alot of people are missing is the torque of an electric motor which you cannot compared with a diesel engine.

 

The reason I do not often post on this forum is the people who shout put of people off who have the knowledge.

Why cannot my figures be accepted over 5 years of development.
With a very full order book 

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2 minutes ago, Keith M said:

It is standard NB built by one of the many fabricators within the UK.

As to weight most have been around 15+ tons.

It is down to design and care of installation, Using correct cable and CSA of cables. and other design features.

I one builder at Crick was stating only around 3 / 4 hours of cursing before recharging and that was Lithums.

 

 

No amount of correct CSA of cables and other design features will allow your boat to break the laws of hydrodynamics -- a standard 60' narrowboat weighs about 18 tons, 1.5kW will push this along at 3kts in deep water but considerably less on a normal UK canal. The normal diesel fitted to such boats is a Beta 43, and prop loading curves say this puts 3kW/4bhp into the prop at 1400rpm, which in my experience is normal open-canal cruising speed -- small wake at bow and stern, wash a couple of inches high at the bank and nowhere near breaking.

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33 minutes ago, Keith M said:

I have just looked at my post and it did say 1.0 / 1.5 kwatts.

What alot of people are missing is the torque of an electric motor which you cannot compared with a diesel engine.

 

The reason I do not often post on this forum is the people who shout put of people off who have the knowledge.

Why cannot my figures be accepted over 5 years of development.
With a very full order book 

Your post as it appears on the forum says "no more than / 1.5 Kwatts"

 

Low-speed torque is irrelevant for driving a prop, absorbed power is what matters -- any basic naval engineering textbook will tell you this.

 

30 minutes ago, Keith M said:

Ian D you do like putting people down who have a better knowledge than you 

Good Bye.

 

Please explain how low-speed torque matters in this case, when driving a prop where the absorbed torque goes up as rpm^2 and the absorbed power as rpm^3.

 

Go on, I'd love to know, as would all the naval architects who've obviously been getting it wrong for so many years...

Edited by IanD
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3 minutes ago, Keith M said:

I have just looked at my post and it did say 1.0 / 1.5 kwatts.

What alot of people are missing is the torque of an electric motor which you cannot compared with a diesel engine.

 

The reason I do not often post on this forum is the people who shout put of people off who have the knowledge.

Why cannot my figures be accepted over 5 years of development.
With a very full order book 

 

If you could bear with those of us who don't have a technical background Keith - could you explain how the torque characteristics of an electric motor make such a difference?  Is it simply because you can fit a much bigger prop than you could for the equivalent power diesel engine?  

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22 minutes ago, Neil2 said:

 

If you could bear with those of us who don't have a technical background Keith - could you explain how the torque characteristics of an electric motor make such a difference?  Is it simply because you can fit a much bigger prop than you could for the equivalent power diesel engine?  

There's no magic here, a prop has no idea whether it's being driven by a diesel engine or electric. Roughly speaking, propeller power goes up as rpm cubed -- actually even a bit faster, bu let's take this as a good approximation.

 

Take a typical Beta 43 diesel with a 2:1 gearbox, allowing for losses this will put 40bhp (about 80lb-ft of torque) into the prop at 2800rpm (1400rpm at the prop), typically with an 18" x 12" prop.

 

Drop the engine rpm by half to 1400 and the power into the prop drops by 8x to 5bhp, torque drops by 4x to 20lbft. The fact that the engine can produce more power and torque than this at 1400rpm (18bhp/90lb-ft) is irrelevant because the prop can't absorb it -- the actual figure is 10x drop to 4bhp from the propeller law curves I have, based on measurements of a real propeller.

 

A bigger diameter or pitch prop absorbs more power at a given rpm, so with the same power it has to turn more slowly -- for example if you use a 2.8:1 gearbox with a Beta 43 you end up with a 20" x 16" prop turning at 1000rpm while still absorbing 40bhp. Again the prop doesn't care what it's being driven by, all that matters is pitch and diameter and rpm. With either a diesel engine or an electric one the gearbox ratio sets the prop size -- or electric motor rpm if it's direct drive.

 

(bigger slower props are a bit more efficient, tiny fast eggbeater ones are a bit less efficient, but the difference is only about +/-10% either way)

 

If you drop engine rpm further then the power and torque into the prop drop even further, so drop the engine to 1100 rpm and the prop power is only 1kW and the torque is lower still (about 10lb-ft). The engine can generate 80lb-ft at full power but the prop doesn't care.

 

This is why the "electric motor has great low-speed torque" doesn't matter when you're driving a propeller -- in a car the situation is completely different and the torque really does help, but a boat isn't a car.

 

These are all basic calculations which are used for design of boat/ship propellers/engine/gearboxes all over the world, not just for narrowboats. If KeithM knows differently then it's time to rewrite all the textbooks, and tell all those marine engineers that they're wrong and he's right...

Edited by IanD
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I suspect at the end of the day a lot of the difference in the power figures being argued above come down to the fact there is no standard speed to operate a narrow boat - as demonstrated in the calculations even a small reduction in speed above makes a big difference in power required. 

 

In one of the posts above, 1400rpm on a Beta 43 is quoted as typical cruising revs. That may be the case for some, but I never use revs that high except on a river pushing some current. I have a 57' standard Liverpool Boat Company hull (so not spectacularly efficient) powered by an Isuzu 35 (not particularly new) and I find my cruising needs are met at typically at  900-1000 rpm whether on deep or shallow canals. At these revs I am moving fast enough for me and am not moving abnormally slowly to impact other boats (in the last three months out, on mainly busy canals, only two boats have caught me up from behind). So accepting that my speed needs are met by relatively low powers then the sums earlier show electric propulsion backed up by solar and limited generator use would probably work well for me.

 

But there is also the other side of the coin. Since I'm already using my diesel at low powers I'm already using considerably less fuel than someone moving faster. So given the current state of technology and electrical infrastructure my feeling is at the moment I shall best limit my environmental impact by using what I have effectively rather than scrapping a working existing resource and buying lots of shiny new, albeit efficient, equipment which all have significant amounts of embodied energy. In five years time maybe things will be different and a change more justified.

 

It's an interesting debate and I'm enjoying reading everyone's input.

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42 minutes ago, Awayonmyboat said:

I suspect at the end of the day a lot of the difference in the power figures being argued above come down to the fact there is no standard speed to operate a narrow boat - as demonstrated in the calculations even a small reduction in speed above makes a big difference in power required. 

 

In one of the posts above, 1400rpm on a Beta 43 is quoted as typical cruising revs. That may be the case for some, but I never use revs that high except on a river pushing some current. I have a 57' standard Liverpool Boat Company hull (so not spectacularly efficient) powered by an Isuzu 35 (not particularly new) and I find my cruising needs are met at typically at  900-1000 rpm whether on deep or shallow canals. At these revs I am moving fast enough for me and am not moving abnormally slowly to impact other boats (in the last three months out, on mainly busy canals, only two boats have caught me up from behind). So accepting that my speed needs are met by relatively low powers then the sums earlier show electric propulsion backed up by solar and limited generator use would probably work well for me.

 

But there is also the other side of the coin. Since I'm already using my diesel at low powers I'm already using considerably less fuel than someone moving faster. So given the current state of technology and electrical infrastructure my feeling is at the moment I shall best limit my environmental impact by using what I have effectively rather than scrapping a working existing resource and buying lots of shiny new, albeit efficient, equipment which all have significant amounts of embodied energy. In five years time maybe things will be different and a change more justified.

 

It's an interesting debate and I'm enjoying reading everyone's input.

Absolutely correct, power increases so rapidly with rpm and speed that how fast you go makes a huge difference -- and this effect is *much* bigger with electric/hybrid boats than diesels, because diesels get less efficient as power/revs fall and still consume fuel when idling, electric motors don't. So dropping speed a bit makes a small difference to fuel consumption with a diesel but a big difference to energy use with electric.

 

The numbers I picked aren't drawn out of a hat, they're based on how fast I travel on the canals, which I'd say is fairly typical (I'm hardly a speed merchant) seeing what happens with other boats in front of me or behind me -- and going by the size of the wakes (and engine noise) I've often seen with boats coming the other way, some people go a lot faster, or at least burn a lot more fuel to go a little bit faster 😉

 

Some people -- you included -- travel more slowly -- and will use less power. Some people don't. YMMV -- literally.

 

However the "low-speed torque" argument keeps being put forward as an advantage of electric motors in boats, and it's just as wrong this time as all the other times, regardless of how many people keep saying it...

 

(there are lots of real advantages with electric drive but this isn't one of them)

Edited by IanD
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1 hour ago, Keith M said:

It is standard NB built by one of the many fabricators within the UK.

As to weight most have been around 15+ tons.

It is down to design and care of installation, Using correct cable and CSA of cables. and other design features.

I one builder at Crick was stating only around 3 / 4 hours of cursing before recharging and that was Lithums.

 

 

Needs a bigger battery bank then! I have 36kwh which I consider right for a days cruising, my motor draws 3.3kw at 3 mph ish [satnavs useless at slow speeds] I have had 2 different motors and the performance was similar on both.

Solar I have 4.6kws which for my sort of summer cruising works fine as well, I do have a 6kw genny as backup

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11 minutes ago, peterboat said:

Needs a bigger battery bank then! I have 36kwh which I consider right for a days cruising, my motor draws 3.3kw at 3 mph ish [satnavs useless at slow speeds] I have had 2 different motors and the performance was similar on both.

Solar I have 4.6kws which for my sort of summer cruising works fine as well, I do have a 6kw genny as backup

You could afford to put a decent sized bank in because you built it yourself using cheap secondhand LiFePO4 batteries.

 

Many of the builders want to put lithium batteries in for all the obvious reasons but they (and their customers) are horrified at the cost, so they put much smaller ones in (e.g. 10kWh) which means they have to recharge a lot more often. A perfectly valid choice, even a small lithium bank can supply hundreds of amps if the right batteries are used, but means they can't run for a day or even two without recharging. Not a problem now (just turn the genny on for less time but more often), but won't be suitable if/when canalside charging becomes widespread... 😉

 

4.6kW of solar on a wideboat is also why this works for you in summer, that's 2x what it's practical to fit on a narrowboat. Also you're on deep wide canals not narrow muddy ditches, which helps keep your speed up and power consumption down...

Edited by IanD
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