Propulsion Power

[Antrepat]

3 hours ago, IanD said:

The problem with LA batteries is not just the charging time, it's the absorption time needed to get them up to 100% SOC and hold them there, which is needed to avoid sulphation.

 

The Leoch PLC batteries (batterystore.co.uk are the cheapest UK source, are partnered with Leoch) have more data available under other labels they're sold under such as Outback (Australian). If you dig into their data sheets, maximum recommended charge current is 0.25C, with about 4h absorption time at 100% SOC. But they are sealed. However this is little real-world experience of them in boat applications because they're relatively new, and they fall into the same "neither fish nor fowl" problem as advanced AGM/cell cells -- they're a lot more expensive than traction cells (about 2x the cost) and still have a lot of the LA disadvantages, and if you're going to pay this much you might as well pay even more and use LiFePO4 and get huge benefits (fast charging, higher efficiency, no absorption to speak of)

 

Traction cells (Tayna cheapest, or pbbatterysolutions?) are designed to be charged back to 100% overnight (>8h charging time) every night, and have similar maximum charge rates and if anything even longer absorption time. This is because they are very tall (typically a couple of feet) and rely on gassing at full charge to circulate the acid, and even then this takes a long time to equalise concentration over the full height. Which also means they *have* to be taken to the bubbling stage regularly to avoid sulphation, which is why fan extraction/venting is needed to prevent building up of explosive gases. Then you almost certainly need an automatic watering system to keep them topped up, which adds to the cost.

 

Having said this, if you do all this (and can put up with the long charging/equalisation times) they're relatively cheap and do last a long time -- when I spoke to Hybrid Marine they said they've got boats out there (all parallel hybrids) after 8-10 years still on their original set of batteries, though obviously without knowing how much they've been used you need to take this with a pinch of salt.

 

https://www.hybrid-marine.co.uk/index.php/products/narrowboat

 

Here's a source for BEV battery packs, much cheaper than new but still pretty expensive.

 

https://www.secondlife-evbatteries.com/collections/ev-battery/Module

 

Bear in mind that these are almost all Li-ion, which need *extreme* care with charging/discharging/protection because if things go wrong the consequences can be catastrophic (battery fires), and there may be consequences for boat insurance because of this -- an issue not often mentioned but I think everyone knows what insurance companies are like, if you don't tell them about the batteries they'll probably refuse any claim. I don't know if the companies who cover UK canals have much experience of Li-ion, but lumpy water companies do and they're very wary of them, especially with home-brewed BMS. I suspect this is the reason why none of the reputable builders of electric boats in the UK have gone down this route, they all use LiFePO4 (the ones who do a "proper job" i.e. an expensive one) -- the cheapskates use LA cells (PLC or traction) with all their disadvantages.

 

The real problem with LA in an electric boat/hybrid where charging is usually from a generator is the long charging/equalisation times -- depending on charging rates, generator run time is at least 2x what you'd predict by dividing required charge by maximum charge rate (can easily be as much as 3x, especially allowing for round-trip energy losses), and for a large part of this time the batteries aren't accepting much current (and it's tailing off) so the generator is running well below full power, bad for efficiency -- as well as wasting fuel, long run times mean servicing is needed a lot more often. You also have to pay close attention to your battery charging regime, making sure to fully charge to 100% SOC and equalise regularly.

 

In comparison LiFePO4 can just be treated as a power bank -- so long as you don't overcharge or overdischarge them (which is why a proper BMS is needed) they don't really care much what SoC they're at, have much higher round-trip efficiency, and need next to no equalisation or care and attention. The biggest bonus is having to run the generator for much shorter times than LA, which is pretty much the entire point of going electric/series hybrid in the first place.

 

Unfortunately they do cost more ?

 

More gold.  Thank you, Ian.

 

I absolutely get what you're saying about there being all sorts of issues associated with using any kind of LA battery, and that lithium simply avoids most of them.  LA is frankly old hat.  Totally sold on lithium, it's a brilliant solution for this application.  Unfortunately new lithiums are totally out of the question for me, so I'll look into these used EV packs.  I'd noticed that EV Li batteries are typically Li-ion, not LiFePO4, yes.  I hadn't even started looking at the full implications of that but I do know Li-ion (and Li-po, for that matter) are far more hazardous.  If Li is still unaffordable or as I suspect too risky for a relative beginner, and I do have to go with LAs, I've got to strike the right balance between affordability, charge rate (actually achieved, not just theoretical), safety (insurance, BSS), and battery maintenance workload (watering, gas venting, frequent enough equalisation, etc.).

 

From that perspective, given all the drawbacks of LAs, it seems to me that they are worst for standard wet batteries, even worse for the traction cell version because of their shape and configuration as you point out, and that the developments like gel, AGM and lead carbon electrodes are efforts to mitigate the issues.  Gel technology was devised (80 odd years ago) to allow a battery that wouldn't glug out its electrolyte if it wasn't upright.  AGM (60 odd years ago) achieves the same but supposedly also improves the charge/discharge characteristics.  Sealed units, VRLAs, suchlike, are low maintenance but don't last as long (because you can't top them up).  Lead carbon, well, "replacing the active material of the negative plate by a lead carbon composite potentially reduces sulfation and improves charge acceptance of the negative plate. The advantages of lead carbon therefore are: - Less sulfation in case of partial state-of-charge operation. - Lower charge voltage and therefore higher efficiency and less corrosion of the positive plate. - And the overall result is improved cycle life."  Hopefully.  "Potentially."

 

I think I must have found the really expensive traction cells, because the prices I noted before weren't half that for the Leoch SLCAs, they were just marginally less:

3 IPZS 420 from PB: bank £2463.60 for 420Ah 48v.

Leoch 400Ah 6v SLCA from Tayna: £320, £2600 for 400Ah 48v (this seems to be a bargain price, I wonder why).

Leoch 145Ah 12v SKCA from BatteryStore: £227.48, £2790 for 435Ah 48v (cheapest combination, includes bulk discount).

and for comparison, ReLiON 12v100Ah LiFePO4 from BatteryStore: £900 each, £14,400 for 400Ah 48v.

 

Like I think I said previously, this business of batteries is a bloody minefield.

 

I won't be living on board, it's a boat for holidays and weekends, so whilst there would be periods of daily discharge/recharge without time for full equalisation, they would be limited to a few days of cycling.  If I go navigating, it could be a fortnight of daily use, but I'd happily settle for a day or two moored within that to allow a thorough equalisation, if that's what's needed to have a battery that is £2600 rather than £14000 or won't catch fire if the BMS isn't right.  And 0.25C is fine - that's 100A at 48v, which is 5kW, and I certainly haven't got room for a generator any bigger than that, and I'm hoping to fit 1kW of solar anyway from which I'd hope to get 2kWh on a middling day.  Every little helps, and that's enough to maintain a nice, gentle, full charging cycle between trips.  If equalisation can only safely be done supervised, so be it.  The boat is at a lovely mooring, I like spending time there, I'm putting in some MiFi gear so I can work there, so doing that to supervise equalisation would be fine.

 

Incidentally, the solar charger I have identified is the  Morningstar TriStar-45, which seems tried and tested, well documented, and fully equipped to deliver charging and equalisation without overcharging (as long as you configure it correctly - RTFM).  I also considered the  Voltacon Conversol S1 - a combined inverter/charger/solar controller, Taiwanese, not much comment about it from users (I found one blog) , typically garbled and vague documentation, and it only does 60A charging and even that's not clear from the docs.  But it's only £650, compared with £375 for the TriStar, £431 for an inverter from RS, and £570 for an 80A 48v charger from PB.  (Higher-power chargers seem basically unavailable, so either I'm missing something, or people put multiples ones in parallel when they want to charge at a higher rate, like wot you'd do with Lithiums for example.)

[magnetman]

5 hours ago, IanD said:

 

 

 

5 hours ago, IanD said:

 

 

Edited March 1, 2021 by magnetman
Edit for multiple post issues

[IanD]

I was comparing traction cells to the Leoch PLC (Pure Lead Carbon), the "superior lead carbon" ones you picked have much shorter lifetimes (also compared to traction cells).

 

The cheapest PLC per kWh are the PLH+C210FT 12V 210Ah which are £450 each -10% for 8, so £3240 for 48V 420Ah.

 

The traction cells have gone up in price since I looked, and also smaller ones (like the 420Ah) are more expensive per kWh than the bigger ones.

 

The cheapest LiFePO4 per kWh are the BYD LVL Premium 15.4 (300Ah 51.2V) which are £6767 inc VAT from bimblesolar -- cheaper from offgrideurope but EU... ?

 

These are 15.4kWh usable, so similar or bigger actual capacity than the LA solutions. About 2x the cost of PLC, about 3x the cost of 2V traction (which get cheaper in bigger sizes), but longer lifetime, and no long charging times.

[magnetman]

5 hours ago, IanD said:

LA traction cells are certainly big and heavy and need careful planning in to fit them into a boat, they're difficult to add on afterwards. The banks used by Hybrid Marine (24 x EPzS 775) weigh about a ton, and cost with auto topup and venting is about 5 grand...

 

Charging by solar during the week (assuming big enough solar panels and enough sun!) and cruising at weekends does avoid the generator problem, also the long equalisation time. But this will need a fairly sophisticated and reliable charging system to charge and then absorb/equalise them while unattended, a week (or more) of overcharging would be disastrous...

 

I do worry about people suggesting that using secondhand Li-ion BEV batteries on a boat is a good idea. When built into a car the BMS is designed/verified/guaranteed by the manufacturer, who has a huge incentive to do it properly (which means, not cheapskate -- the electrics are a typically at least a third of the cost of the car) because having them catch fire and burn cars out is bad publicity -- and the insurance companies are aware of all this and allow for it. They also make them in large volumes so any bugs in the system are likely to be found and fixed.

 

Now consider people using these Li-ion packs second-hand on their boats with a DIY (or bought-in from bits) BMS, and doing it all on the cheap -- which means the reliability/fault-tolerance/protection/idiot-proofing is likely to be to a far lower standard than in a car, with very few of them out there to find any problems. And when things go wrong with Li-ion they go really wrong, putting out a battery fire is not for the faint of heart -- or even many (most?) fire brigades.

 

Put all this together and I very much doubt than any insurance company would touch Li-ion on a narrowboat with a bargepole, unless it was a properly designed and installed system from a reputable commercial supplier who can demonstrate the same design/safety/regulation standards as Li-ion cells in BEV. Which costs an absolute fortune to do, and certainly wouldn't be the cheap solution that everyone is looking for.

 

LiFePO4 is a different matter, these are *much* safer and easier to deal with. But almost all BEVs that these battery packs are coming from (Tesla, VW, BMW) are Li-ion because the higher power density is critical for cars...

Good points but it's worth pointing out that "Lithium Ion" does in fact include the LiFePo4 chemistry. It is a generic term rather than one which refers to a specific type of lithium battery. 

 

Other than that slight misdemeanour I agree with the caveats in your post and it was well constructed. 

 

 

 

 

5 hours ago, IanD said:

 

 

 

 

 

 

 

Edited March 1, 2021 by magnetman
Edit the remove the sex references

[Antrepat]

4 hours ago, Tony Brooks said:

 

As hydrogen is considerably lighter than air I would have though providing you organised decent engine room vents above the deck board level the hydrogen would naturally disperse. Any fan would have to be explosion proof or you would have to blow into the bilge so any hydrogen is vented through a passive vent. You would also have to take steps when working around the batteries to disperse any local pockets of hydrogen.

Very good advice, Tony, thank you.  I think I could manage a ducted draught to blow around the batteries, as you suggest, rather than drawing the air over them and out through the fan.

[magnetman]

https://www.tayna.co.uk/leisure-batteries/sonnenschein/

 

Innit

[IanD]

Just now, magnetman said:

Good points but it's worth pointing out that "Lithium Ion" does in fact include the LiFePo4 chemistry. It is a generic term rather than one which refers to a specific type of lithium battery. 

 

Other than that slight misdemeanour I agree with the caveats in your post and it was well constructed. 

 

 

 

 

Good points but it's worth pointing out that "Lithium Ion" does in fact include the LiFePo4 chemistry. It is a generic term rather than one which refers to a specific type of lithium battery. 

 

Other than that slight misdemeanour I agree with the caveats in your post and it was well constructed. 

 

 

 

 

Glad to see my post was so good you quoted it twice ?

 

Agreed that "they're all Li-ion", but normally this term is used for Lithium Cobalt Oxide (LCO) or Lithium Nickel Manganese Cobalt Oxide (NMC) or Lithium Nickel Cobalt Aluminum Oxide (NCA). all of which share the desirable feature of high energy density with the undesirable feature of burning ferociously and almost unstoppably at a very high temperature if things go wrong like massive overcharging or a cell short -- these are what normally get lumped together as "Li-ion" from a hazard point of view, which insurers don't like.

 

LiFePO4 (LFP) batteries are lower density and can be lower cost (which is why Tesla are using them for some cars in China) but are much safer, these are the only lithium batteries that anyone sane should be considering using on a boat ?

[magnetman]

As someone who has experienced a thermal runaway of a "lipo" type which was probably a LiCo battery due to overcharging I agree with you.

 

It was a jump start pack, I had made my own leads as lost the original ones which had a diode pack and I left it connected after engine started. Due to the fact it was a 3S LICo (probably) battery the 14+ volts it received was not welcomed by the device. It started smoking, I removed it from the engine room and hung it off the side of the boat. Thermal runaway proceeded and a quite nasty flame-out. I still have not painted over where it burnt the paint off the boat. 

 

 

So yes the risk is real with these things. It was like setting fire to a can of petrol with a 20:1 2 stroke mix. Something I did a lot of when I was younger. 

 

 

[magnetman]

To be fair you could use a non LFP battery system and get away with it if it was done right. I suppose it's a bit risky to recommend it as in a lot of cases it would not be done right. 

 

There will be insurance claims around this. 

 

Luckily I have work based insurance and it covers everything I post in a professional capacity. 

 

 

[Alan de Enfield]

4 minutes ago, magnetman said:

20:1 2 stroke mix.

 

 

Seagull ?

[Antrepat]

1 hour ago, IanD said:

Most LA batteries are happy being charged at 0.25C, including traction, AGM, gel and lead-carbon, so long as there's proper control of absorption/float voltages to prevent overcharging. The bigger PLC batteries can be charged at 0.25C, see attached data sheet from Outback (badged Leoch pure lead carbon).

 

Sealed batteries like the Leoch PLC (or AGM or gel?) don't give off any gases in normal operation and don't need any venting. Traction cells do, and do.

enegycellPLC_specsheet.pdf 336.37 kB · 2 downloads

 

OK, that simplifies things (thank goodness).  Someone said, I think it was you Ian, that you can reckon on £5k for traction cells with a watering system, or spending a lot of time crouching about dribbling distilled water into small holes since venting gas is part of the necessary charging cycle of this type more than any other, and if you don't do it right you'll soon end up with knackered cells.  I can't imagine ordinary-shaped LAs (your classic wet cell deep cycle leisure battery) would really be much better.  None of that faff is necessary with sealed types, but they may not last as long.  So, I'm seeing the balance of costs much better now: £5k for traction cells with watering and very careful charging; or £2.6k for sealed lead carbons with much less maintenance but still needing careful charging; maybe £8-9K LiFePO4 if you are OK getting them on Ebay (I've just discovered), or hazardous and complicated used Li-ion from EVs.

 

I mean, put like that...

[Antrepat]

34 minutes ago, IanD said:

I was comparing traction cells to the Leoch PLC (Pure Lead Carbon), the "superior lead carbon" ones you picked have much shorter lifetimes (also compared to traction cells).

 

The cheapest PLC per kWh are the PLH+C210FT 12V 210Ah which are £450 each -10% for 8, so £3240 for 48V 420Ah.

 

The traction cells have gone up in price since I looked, and also smaller ones (like the 420Ah) are more expensive per kWh than the bigger ones.

 

The cheapest LiFePO4 per kWh are the BYD LVL Premium 15.4 (300Ah 51.2V) which are £6767 inc VAT from bimblesolar -- cheaper from offgrideurope but EU... ?

 

These are 15.4kWh usable, so similar or bigger actual capacity than the LA solutions. About 2x the cost of PLC, about 3x the cost of 2V traction (which get cheaper in bigger sizes), but longer lifetime, and no long charging times.

 

Oh, sorry Ian, didn't realise.  Actually I found the pure LC ones for £404.98 from BatteryStore - you get a 10% discount if you order 8, then £60 for delivery is £3,300.  You're right, these do seem to be much more robust than the SLCAs, and they weigh 61.6kg, so a bank comprising 8 would be about 500kg, only a bit more than the SLCAs.  They're the ones claiming a 0.9C charge rate, which I've been scoffing at but no one has joined in!  Anyway, that's £700 more but potentially a lot more resilience and longer life.  The BYD packs are much cheaper, I see.  That's a big difference from £14600.

[magnetman]

46 minutes ago, Alan de Enfield said:

 

 

Seagull ?

It was a seagull featherweight. 

 

Mother used to authorise me to buy fuel for it but when taking the dinghy out on the River Thames got too boring we (a "friend" and me) used to pour the diluted petrol in the cracks of the collapsing concrete bank at the bottom of the garden and see what happened if you dropped a lighted match in. 

 

River police stopped to check a couple of times but mother was always authoritative and told them to clear off ! 

 

True story. 

 

The one with the scared rower was funny. Burning can of petrol floating down the River towards neighbours boat I had to explain "it's ok it is a 20:1 two stroke mix it will not be a problem" he did seem worried it would burn uncontrollably but it wasn't going to. 

 

This was after I had chosen to add more petrol to the concrete experiment and set fire the the container. "Best to throw it in the River" was my thought. 

Edited March 1, 2021 by magnetman

[Antrepat]

43 minutes ago, magnetman said:

To be fair you could use a non LFP battery system and get away with it if it was done right. I suppose it's a bit risky to recommend it as in a lot of cases it would not be done right. 

 

There will be insurance claims around this. 

 

Luckily I have work based insurance and it covers everything I post in a professional capacity. 

 

 

 

As someone who's quite new to various aspects of all this, I think I'd be best avoiding adventures with the more hazardous types of lithium battery for now - sorry Peter, but I don't think I quite have your chuztpah yet!  Maybe I should play the lottery or rob a post office, buy LiFePO4 and all this will be simple.

[magnetman]

1 minute ago, Antrepat said:

 

As someone who's quite new to various aspects of all this, I think I'd be best avoiding adventures with the more hazardous types of lithium battery for now - sorry Peter, but I don't think I quite have your chuztpah yet!  Maybe I should play the lottery or rob a post office, buy LiFePO4 and all this will be simple.

I'm andrew not Peter and I was the one recommending buying gel cells

 

LFP is interesting but at the end of the day you need to have the funds. It's easy for people who do have the funds to say it is the answer but if you don't then it isn't. 

 

Newer battery tech is always going to be more expensive. Bolinders engines were probably more expensive than horses but there was a business case for adopting them as propulsion units. 

 

i still think that a land based traction system like a mechanical horse of some sort might end up being the answer overall for canals. Without sufficient dredging propellers, which rely on water, become less and less effective..

 

This is sometimes not that obvious but when you are sucking the bottom in a deep draught vessel you do tend to wonder about it.

[Antrepat]

14 minutes ago, magnetman said:

I'm andrew not Peter and I was the one recommending buying gel cells

 

LFP is interesting but at the end of the day you need to have the funds. It's easy for people who do have the funds to say it is the answer but if you don't then it isn't. 

 

Newer battery tech is always going to be more expensive. Bolinders engines were probably more expensive than horses but there was a business case for adopting them as propulsion units. 

 

i still think that a land based traction system like a mechanical horse of some sort might end up being the answer overall for canals. Without sufficient dredging propellers, which rely on water, become less and less effective..

 

This is sometimes not that obvious but when you are sucking the bottom in a deep draught vessel you do tend to wonder about it.

 

I know, Andrew, but Peter has been the main advocate during this discussion of the used EV battery option.  That's what I was referring to.

 

You're absolutely right, and I haven't got the funds and I'm not kidding myself that it's really an option.  Ian's case is convincing and I'm convinced, I just can't afford it.  I'm at the level of second hand equipment if I can find it, motor, controller, chargers, generator.  Peter for one seems to be good at knowing where to get that kind of stuff (and he lives in Rotherham, which is actually not far from my mooring), but the one thing that really has to be new is batteries since I can't afford the kind that don't wear out.

 

I think what we need is AI-piloted drones to draw us along.  I'm sure that'd be completely practical and not at all dangerous.  The mechanical horse would suffer the same problems as the real ones: cyclists, runners, people who get stroppy about the towing path being used for towing, etc.  Wait...how about paddle-wheels?

Edited March 1, 2021 by Antrepat

[magnetman]

Thanks for clarifying that. I sometimes get misunderstood and misrepresented and misidentified. Among other misses this can cause quite serious issues so apologies if it seemed over the top but in this case I misunderestimated you. 

 

[Antrepat]

2 minutes ago, magnetman said:

Thanks for clarifying that. I sometimes get misunderstood and misrepresented and misidentified. Among other misses this can cause quite serious issues so apologies if it seemed over the top but in this case I misunderestimated you. 

 

 

Well I'd be mystified if there were any remaining mistake or misapprehension.

[magnetman]

46 minutes ago, Antrepat said:

 

I  The mechanical horse would suffer the same problems as the real ones: cyclists, runners, people who get stroppy about the towing path being used for towing, etc.  Wait...how about paddle-wheels?

What you do is just remove the permission so no public allowed on towpaths..

 

I suppose this would cause some issues with non commercial boat operators. 

 

Maybe it's worthwhile looking at commercial opportunities. Perhaps someone who does an entirely pointless vlog about narrow boats would be able to continue using the towing path for their mechanical horse due to the commercial use of their vessel. 

 

Blatant Pleasure Seekers should be banned anyway as that is not a valid use of boats. 

 

 

Edited March 1, 2021 by magnetman
Edit to add terrible jokes

[peterboat]

1 hour ago, Antrepat said:

 

As someone who's quite new to various aspects of all this, I think I'd be best avoiding adventures with the more hazardous types of lithium battery for now - sorry Peter, but I don't think I quite have your chuztpah yet!  Maybe I should play the lottery or rob a post office, buy LiFePO4 and all this will be simple.

I do have LifePo4s when it wasn't popular it was as cheap as chips! Which is why I bought loads of them 

Since then I have built battery banks up using other lithium chemistry (polymer) which is in my little electric car, I have battery balance boards on them. 

Edited March 1, 2021 by peterboat

[Antrepat]

Incidentally, I got the following response from PB about the 2v traction cells. The equalisation frequency is interesting - I mean, an hour once a month is hardly a chore - but he didn't answer my actual questions which were about maximum and recommended charge and discharge rates, and for some kind of datasheet. It seems astonishing that they don't know that kind of thing. If you can only charge at 0.1C...thank goodness Ian knows better.

 

Peak bulk 64.32v

Absorption 57.6v

Float 53.52v

Equalise - 1x per month for 1 hour - 62.4v

 

£1998.00 ex vat. 

[peterboat]

5 minutes ago, Antrepat said:

Incidentally, I got the following response from PB about the 2v traction cells. The equalisation frequency is interesting - I mean, an hour once a month is hardly a chore - but he didn't answer my actual questions which were about maximum and recommended charge and discharge rates, and for some kind of datasheet. It seems astonishing that they don't know that kind of thing. If you can only charge at 0.1C...thank goodness Ian knows better.

 

Peak bulk 64.32v

Absorption 57.6v

Float 53.52v

Equalise - 1x per month for 1 hour - 62.4v

 

£1998.00 ex vat. 

That doesn't seem right? Equalise is normally higher than bulk, as I said I had these as leisure batteries for years worked ok but very heavy 

[Antrepat]

2 hours ago, peterboat said:

That doesn't seem right? Equalise is normally higher than bulk, as I said I had these as leisure batteries for years worked ok but very heavy 

Yes, that's what I thought too - the purpose of equalisation is to max charge the battery for a controlled amount of time, to get that lead sulphate fully dissolved, isn't it?  If they'd give me the damned datasheet for the cells they use, we'd be able to make sense of it, I dare say.

Edited March 1, 2021 by Antrepat

[Antrepat]

Anyone know anything about this one?

 

https://www.voltsport.co.uk/voltsport-marinepropulsionsystems/beltdrivesystem

[DHutch]

On 26/02/2021 at 17:26, TheBiscuits said:

Funny things steam whistles.  A few years ago I very nearly hit @DHutch on Emily Anne at Litherland swing bridge - he had clearly whistled but my brain didn't register it as a boat noise at all until I came round the blind corner and he was right there in the bridge narrows.  I wasn't speeding though, so stopped before bouncing off him!

 

You are not the first, and no doubt are not going to be the last!