IanD

That figure was taken from actual efficiency curves for a Beta 43 with standard prop, about 19% efficient at 3kW/4hp output at 1300rpm -- see attached plot. Peak efficiency is 32% around 2000rpm, but this will never be reached when driving a prop (blue line). A condenser should mean higher efficiency than a direct exhaust like a railway loco, that's the whole point -- yes heat goes out of the condenser into the cooling water, but less energy is lost overall than by just throwing the steam away, especially since the expansion ratio can be bigger. But maybe with only double compounding this isn't that big an advantage... As you say compounds are less sensitive to cutoff than simple expansion engines (and use longer cutoffs anyway), and also more efficient -- even non-condensing ones.

Just imagine the number of pages of whining on CWDF if CART went to (logical!) area-based pricing... 😉

Given that their lifetime is so much shorter, that's kind of necessary... 😉

Mixed Young's Ram (bottled) and Special (draught) used to be popular in London... 😉

Including costing 4x as much? I'm sure that'll go down well with those doing possibly-problematic LFP installs "on the cheap" as noted above... 😉

As do Fogstar and various other suppliers. But if you're looking to rabbit on endlessly about LFP problems -- real or imagined -- this doesn't matter... 😉

And in that case if the batteries get cold and there are no heaters, they won't be able to charge them. That's not the fault of LFP batteries, that's the fault of whoever designed/bought/installed a crappy LFP system on the cheap and without thinking -- probably also with parallel LA and long wires, and a BMS that gets hot at high currents and dies after a few years. Nobody made them do it... 😉

When we're out cruising (series hybrid boat) I normally start the (very quiet, cocooned diesel) genny up at 8am while we have tea in bed, which heats the water up and charges the batteries -- or if we're not going anywhere and don't need the power, I do the same with the diesel boiler. Either way, there's plenty of hot water when we get up and shower. Same thing before we stop in the afternoon/evening if we want showers then. In between the hot water cools down, but it's still warm and there's usually enough for at least one shower at any time. I guess that's the disadvantage of not running a diesel engine all day, you need to think a bit more... 😉

BYD -- who are the world's biggest LFP manufacturer, *hundreds* of times bigger than Victron, and make their own cells and BMS from scratch -- start to reduce charge rate below +12C but allow charging at reduced rates all the way down to -10C, see numbers I gave above. The low-temperature requirement is driven by off-grid domestic installs in cold countries which is a *huge* market, far bigger than boats, and that's what pushed BYD allow lower-temperature charging -- they updated their software about 3 years ago to do this. I'm sure Victron -- who are much smaller and relatively new to the LFP game, but still far bigger and better-resourced than the small cheap BMS manufacturers -- will catch up eventually, because that's what their markets will demand... 😉

Which is why I'm not worried about it... 🙂 See post above about what a properly designed/integrated BMS/LFP system should do, as opposed to cheap nasty off-the-shelf BMS from China... 😉

Even so, he's still wrong for properly managed LFP/BMS systems, see the numbers I quoted. The fact that a lot -- especially cheap ones -- just go from full rate above 0C to zero below just shows how little their designers understand LFP batteries... 😉

That's pretty poor then. A narrowboat diesel engine at cruising power is about 20% efficient, a big single-expansion superheated high-pressure non-condensing steam engine (railway engine) might manage 8% at peak efficiency but rather less at low power levels. Compounding and condensing both push efficiency up, but having a small low-power engine pushes it down again (more surface area and frictional losses). Even so 10x the consumption implies about 2% thermal efficiency which is pretty appalling... 😞 Out of curiosity, what boiler pressure do you run at? (I assume the engine is not superheated)

The last one isn't surprising, about 10x the fuel consumption for 10x the displacement... 🙂 The first one is pretty surprising though, given sensible guesses for the thermal efficiencies of a non-condensing single-expansion steam engine (is that what you have?) and a diesel engine I'd have expected a difference of a few times (3x-5x?) but not 10x. But then so much depends on the details, if you don't have variable cutoff valve gear and reply entirely on throttling to vary power (do you?) then 10x is perfectly reasonable... 😞

I assume you mean 0.5C? 5C is quite large, 500A for a 100Ah battery (which probably has a 100A BMS)... Low temperature charging is another area where the integrated battery/BMS suppliers can do much better, rather than just stopping charging completely at 0C as many do. For example, the BYD 14kWh 48V pack (280Ah) has maximum charging current of 160A (0.6C) from +12C to +50C, 80A (0.3C) from +2C to +12C, 60A (0.2C) from -10C to +2C.

This is like two bald men arguing over a comb -- lithium batteries on canal boats are likely to outlast the owner and maybe even the boat, so long as they're treated properly for charge and discharge -- the ambient temperatures are generally suitable for them, and several thousand cycles at 100% DoD (or 2x-3x that at more usual DoD) means lifetime will be so long as to be not worth worrying about. Here's an example of 15 years of heavy use -- much heavier than most boats! -- with close to zero capacity loss... 😉 (but with a properly designed BMS...) https://marinehowto.com/happy-15th-birthday-to-my-lifepo4-battery/