Jackofalltrades

Yes I am aware of changes coming from 2025 for new boats and the plan to make all boats 'green' eventually. But that is presently a long way off and I would not be in the least bit surprised to find that the tax on marine diesel gets increasingly hiked to encourage the switch. In fact I would put money on it happening.

Martyn, the government is coming under increasing pressure to phase out fossil fuels. It doesn't take a genius to work out that they may well go after the easy targets first - one of which would be leisure boats. As almost all leisure boats get their fuel from marinas and boat yards it would be very easy for non-commercial purchase of marine fuel to be taxed at a higher rate. I'm not saying it will happen - I know nothing - but I can easily see that it might, and probably at some point will. Regardless, there is already increasing societal pressure to reduce carbon emissions. And then there's diesel particulates from old diesel engines... The lung damage caused by pollution and the effect it has on life expectancy is now known and (mostly) accepted. The problem won't go away on its own. And in my humble opinion, we should all take our fair share of responsibility for it and take mitigating action if and/or when we can.

We plan to constantly cruise for approx 8 months of the year. We'll constantly cruise more slowly when the weather isn't conducive to PVs doing their stuff or if we really want to move (moored next to someone who keeps telling us that our system won't work ? ) then we'll fire up the generator. Both ends of our cruising year will require some generator use too but we hope to minimise that by staying in one spot for several days where possible to minimise fuel use & pollution.

Yes, and catalytic converters, DPFs, AdBlue and turbos will increase purchase and running costs. Plus with fossil fuels being increasingly demonised pressure will grow on the government to increase fuel tax to encourage people to switch to cleaner and/or renewable sources of energy for everything including boat propulsion. And boat owners would be a soft target if the government wanted to particularly increase taxes on non-essential use of fossil fuels. On a different note, is anyone aware of the new solar panels coming in a year or two? Currently approx 20% of the sun's energy can be converted to electricity with a photovoltaic solar panel in real-world conditions. The new panels are said to be approx 30% efficient - again in real-world conditions (approx 40% in a lab, apparently). I understand several PV manufacturers are in early production planning stages. I don't like gin. I like wine.

A good point. Well made.

Arguing about a fraction of a fraction of a litre of diesel ? A first world problem I guess!

It would have cost the previous owner a lot more, yes ?

Generator diesel consumption. Here's the spec sheet for the generator installed on our sailing boat: https://static1.squarespace.com/static/55c3192ce4b099b364749dbb/t/55c88178e4b035759ce3bb2f/1439203704637/Paguro-6500-8500-Marine-Generator.pdf Fuel consumption is stated as: 0.35 l/KW/h

So what was your back-up plan in case it all went Pete Tong? You had a back-up plan, right?

That's why I said in my previous post "Tidal streams are always checked / worked out before setting off on passage to take advantage of them, not to battle against them **if at all possible.** " ...If anyone thought the motive power source (diesel or electric) on their boat was marginal for the conditions (i.e. left no margin for error) then they should be inclined to wait for more favorable conditions. But we're talking here about heading a few miles up river not crossing Biscay or the English Channel & shipping lanes, or timing an arrival at a ferocious tidal gate, etc. Now before anyone pounces on me, I doubt any of us who have been around boats long enough are complacent (surely not) and yes I know everyone makes mistakes and forecasts and local experts are sometimes wrong, etc, etc, but if we want to be as safe as it's possible to be all the time then best to hide under a duvet all day (and then get wiped out by a crashing plane...) I suppose what all this boils down to is: know thy boat and know thyself! And plan accordingly, with as wide a margin for error as you deem appropriate for you, your boat, and the conditions both actual, forecast and worst case. But from my so far limited knowledge of the UK's inland waterways it seems that more boats are sunk on their moorings and in lock incidents than through lack of power (perceived or otherwise).

Our other boat is a sailing boat. Tidal streams are always checked / worked out before setting off on passage to take advantage of them, not to battle against them if at all possible. I fully expect we'll do the same on the canal and river network where and when appropriate. I'd consider it to be poor seamanship to do otherwise. As for the ongoing debate concerning how many HP is enough. Well, in't olden days it wa one real 'orse per boat. Twenty 'orses or more... luxury!

I get the point about assembled batteries but in the absence of a written specification stating that what you are guessing is correct I'm guessing it probably isn't. Can I ask what experience you have with these batteries?

I do hear what you are saying but going down the (more expensive) lithium route seems risky from where I'm standing at the moment and the secondhand lithium battery route seems potentially fraught. Would it be possible for you to describe your setup in detail? I appreciate you might not want to though.

Maybe, maybe not. My only experience so far with lithium is with laptop batteries (Li-ion) and cordless tools. Oh and my shavers. And the toothbrush. And my phones. And, er, well, they're everywhere aren't they... OK, let me spell it out: - Budget is a factor (isn't it always) - A drop-in 48v LiFePO4 pack with a minimum of 300Ah usable to 80% DoD and charge to 95% SoC would be tempting - so 400Ah or 19.2KWh minimum - A DIY version of the above - I would want a guru on speed dial - Budget is a factor (have I said that?) £6K I can live with. Much more than that and the leather on my wallet starts to peel (well they said it was leather) - Safety - no compromises Now don't get me wrong I am open-minded and I have maybe two months before having to clean the dust off the dust on my wallet but at this stage, on balance, I still think lead carbon is the way to go and apart from anecdotal evidence I haven't yet seen anything to get me running for the hills. Yes the price difference isn't that great but the usable capacity of the lithium is only 240Ah compared to 300Ah for the lead carbon. 300Ah (usable) is the minimum I want to install.

On balance, although I am electrically-minded and can turn my hand to most things (successfully!) I am nevertheless cautious with going down the lithium route. There is far more to lithium batteries than lead batteries and although I'm all for taking calculated risks and learning new stuff my gut feeling is to stick with lead, albeit probably lead carbon, batteries. I see LC as a half-way house between flooded LA traction batteries and lithium so I can't be called a complete Luddite ...or should that be Leaddite? ?

The Leoch's you've quoted are the LRC2 not the LC2 that I would use. The LC2 600's can be found for £245 x 24 = £5880 inc VAT The BYD is £6,377.21 inc VAT The smallprint on the BYD LiFePO4 spec sheet stats " [1] DC Usable Energy, Test conditions: 100% DOD " I would not be happy stressing the battery to this level. Good practice is 80% DoD and charge to 95% so 75% usable capacity of 15.4KWh = 11.55KWh or 240Ah

600AH @ 48v minimum. 800AH would be better but probably not necessary from an expected 50% DoD / cycle life / cost point of view. Cost difficult to say as we haven't decided which batteries we'll go for at present. Lithiums (LiFePO4 not Li-ion) would be a budget blower (yes I am aware of ability to use a higher DoD but good practice seems to suggest 80% DoD and only charge to 95% for long(er) life). The Leoch 2v lead carbons have a stated cycle life of approx 3,300 at 50% DoD. This is the spec sheet for the 800AH battery http://www.leoch.com/pdf/reserve-power/leadcarbon/LC2-800.pdf

Yes 48v. Interested in why you think the 2v cells won't work. They have a higher stated cycle life that the equivalent 12v batteries and I can't find anything (apart from what you've just said) that suggests they won't work. Might be interested in secondhand batteries but it depends on price, age, cycles consumed already (how do you know?) and capacity. Is there an online seller?

Well, lead carbons are much better than flooded and better than gell and AGM. Weight isn't an issue (ballast) and although lithiums are better - no denying it - lead carbons are significantly cheaper. Victron MPPT and Quatro charge controllers will ensure the batteries are charged correctly. Batteries need looking after. What we've done thus far is check the weather forecast and if it looks like being a sunny day and the batteries aren't too discharged then let the solar look after them. Less good weather and/or batteries more discharged then crank up the generator for a while in the morning and let the solar top the batteries off. ...Although lead carbons lessen the worry about partial state of charge. As I've said, everything is a compromise.

We have a sailing boat with 400w solar array so we have a good feel for output. In the summer that's more than enough. In December - not worth mentioning. But as most of our canal cruising will be done in the summer the 2.2Kw array should be sufficient if we don't cruise every day. As I said, spring/autumn generator will be required to supplement the solar. Winter months we''ll be on shorepower. We'll be very happy if we only have to run the generator 20 - 30% of the time. We think that's doable on average. We'll see.

Yes, trees. We'll carry a chainsaw. < joke. We'll manage as best we can, dodging the rain, trees, shadowing from clouds and Grockles passing by... Only the shell is on order. Batteries - not ordered yet - but leaning towards Leoch 2v lead carbon. Lithium too expensive. By the time the lead carbons are ready to be retired lithium batteries will be old tech and dirt cheap and we'll probably be discussing solid state batteries or something more exotic. Everything is a compromise. Yes, fully installed marine diesel generator. Hopefully fitted in the bow but that's still to be discussed with the shell builder to see if it's really possible. Can't say I'm aware of many narrowboats with gens in the bow? Nice cat BTW. FP Athena?

No salesmen involved! All based on my own research, reading and power audit. We know a generator will be needed as there are no CRT shorepower points along the canals and we want to be out there cruising as much as possible with the least amount of pollution possible but still have a life! Summer should be OK mainly on solar. Spring/autumn generator required to supplement the solar. Winter = negligible solar so into a marina and plug in to shorepower.

No, using solar to avoid running the engine/generator has very different benefits. On a diesel engined boat all the solar will do is charge domestic batteries. If you want to move the boat you have to fire up the diesel engine. On an electric propulsion boat the solar will charge the propulsion batteries. If you want to move the boat you do not have to fire up the generator. Edited to add: Are we talking about the same things? I'm comparing a serial electric propulsion narrowboat with solar array and backup generator to a conventional diesel engined narrowboat.

A very interesting discussion, especially as I (we) will soon be going down the electric propulsion route on a narrowboat shell. However, although it is interesting to see a fair comparison of hybrid and straight diesel systems, what the comparison seems to be failing to take into account is the much larger solar array on an electric propulsion boat. A diesel powered boat might have say 600 watts of solar (an average?) solely to keep the domestic batteries charged whereas a boat with an electric motor as a sole means of propulsion will have as much solar on the roof as it's physically possible to install and from my own calculations I will be disappointed if we end up with less than 2.2 Kw. In the summer months when most cruising is done we expect (from what we have read elsewhere) to be able to cruise for a day on battery power and solar alone. We then plan to spend a few days in each location wherever possible to maximise solar charging of the batteries (weather permitting) before setting off for another day of cruising. For our use case we expect our diesel generator usage to be negligible in the summer months and outside of these months we still expect the solar array to make a noticeable contribution to the battery bank - especially as we would be moving less when it's colder and wetter - and in the depths of winter the boat will be in a marina on shorepower. We think our diesel use over the course of a full year of cruising will be somewhere in the region of 70-80% less than using a straight diesel engine for propulsion. That's 70-80% less pollution too. That's the theory anyway. I'll post some real life figures after the boat is launched early summer, all being well. Edited to add: Hello everyone - I've lurked for a while and only just realised this is my first post.