Interested minds ... (boat electrical systems, the 'Big picture').

[T_i_m]

1 minute ago, Tony Brooks said:

 

The last point. This is why best practice is to mount any motor driven water pump vertically, with the pump part below the motor.

 

As this is a liveaboard one common cause of these pumps leaking is less likely, that is water in the pump freezing and forcing the plastic parts apart.

 

Sometimes tightening the screws holding the pump body together a little cures the leak, BUT as the screws are just self tappers into the plastic body, it is all too easy to overtighten and strip the plastic body thread.

 

It is not unknown for the diaphragm that works the pressure switch to leak, but that comes from the end of the pump, not from the joint(s) between the main plastic pump body.

 

Yes, you can get overhaul kits, but experience suggests that even when you fit one, it is not always possible to rebuild with no leaks. I consider such water pumps as consumable items.  If tightening the screws does not work I would fit a new pump, and then by all means try fitting an overhaul kit, so if it does not leak the boater has a spare. I have a feeling the difference in price between the kit and a new pump is not very great.

 

Once again thanks for the prompt reply and info Tony.

 

Again, it's difficult for me when trying to help my friend remotely and my own responsibilities (being the full time carer for my wife being the main one) meaning that I can't easily just 'pop up there' to check these things out for myself.

 

So when a failed gasket is mentioned I'm not exactly sure what we are dealing with, given the pump was working and only had a small seeping type leak.

 

Checking the Internet it seems there are quite a few people who have issues with their Jabsco pumps (especially new ones only lasting a month or two) but that could be a function of one 'lemon' model or production batch or simply because they sell 10x more pumps than the next brand?

 

Then you look to Seaflo as they are cheaper but read reports of poor customer service etc. ;-(

 

One responder suggested he had rarely had any issues with Flojet pumps when commercially maintaining RV's over many years but again, how many of each brand / model were they seeing?

 

The problem with me recommending 'something else' in the hope that it offers him a better / more reliable service is that I have no field experience of these and it may well be that recommending Jabsco is like the “Nobody gets fired for buying IBM”?

[Tony Brooks]

4 minutes ago, T_i_m said:

Is there such a thing as too much pressure with these domestic water pumps (within reason of course) and if so why please?

 

I ask because it seems there are more options if you are looking for a 12V, 15 l/m (min) pump in the 3 - 4 bar range (~ 40/60 psi) than to match the existing 25 PSI (~1.8 bar) offering?

 

I can't imagine the extra pressure would put most domestic plumbing or devices (head, sink taps or shower etc) at risk but maybe it could?

 

Yes, about as long-lasting and reliable as any other make of pump of this design. Some hold them to be less long-lasting than Jabsco. You can always adjust the cut-out pressure on the pump (screw usually in the end of the pump)

[T_i_m]

Just now, Tony Brooks said:

 

Yes, about as long-lasting and reliable as any other make of pump of this design. Some hold them to be less long-lasting than Jabsco. You can always adjust the cut-out pressure on the pump (screw usually in the end of the pump)

Thanks again for the reply Tony.

 

This looks to be the current replacement for my friends leaking pump ...

 

On the question of pressure though, what is it that determines what is 'right'? I get you need enough to say provide a decent shower (along with flow rate etc) but given you can manage both with the tap, when would it be 'too much'?

 

If his current setup has been working at 25 PSI (cutoff), what would change if he replaced it with a 40 PSI pump?

 

[David Mack]

14 minutes ago, T_i_m said:

 

On the question of pressure though, what is it that determines what is 'right'? I get you need enough to say provide a decent shower (along with flow rate etc) but given you can manage both with the tap, when would it be 'too much'?

The most pressure-sensitive component of the plumbing system is usually the calorifier. That's why they are fitted with a pressure relief valve, which will vent any excess pressure (which could arise either from the water pump or the expansion of water as it is heated). So whatever maximum pressure the pump is capable of providing, needs to be no more than the PRV pressure. The cut out pressure on the water pump should be adjustable, or you can fit an external pressure switch to do the same.

[Alan de Enfield]

23 minutes ago, T_i_m said:

On the question of pressure though, what is it that determines what is 'right'? I get you need enough to say provide a decent shower (along with flow rate etc) but given you can manage both with the tap, when would it be 'too much'?

 

I have found the regular (annually) servicing and de-scaling of taps and shower heads is more important than the pump pressure.

 

The build up of fluff / muck / rust / lime scale in the tiny filter inside the tap spouts, and the shower head holes is amazing. 

Cleaning the shower head can result in going  from a 'dribble' to (almost) a power-shower.

[Tony Brooks]

32 minutes ago, David Mack said:

So whatever maximum pressure the pump is capable of providing, needs to be no more than the PRV pressure.

 

In theory yes, but as closing an outlet has been known to produce pressure pulses in the pipework that jumps the PRV off its seat I would suggest no more than about 5 psi below PRV opening pressure, so 3 bar PRV (say 45 psi), no more than 30 PSI operating pressure. Remember, any accumulator and expansion verse may need their air pressures adjusting to suit.

[T_i_m]

1 hour ago, David Mack said:

The most pressure-sensitive component of the plumbing system is usually the calorifier. That's why they are fitted with a pressure relief valve, which will vent any excess pressure (which could arise either from the water pump or the expansion of water as it is heated). So whatever maximum pressure the pump is capable of providing, needs to be no more than the PRV pressure. The cut out pressure on the water pump should be adjustable, or you can fit an external pressure switch to do the same.

Hi David (I thought I replied to this so sorry if it appears twice).

 

One thing I've not touched, or even seen on the Nb so far (and I'm from that 'what you do you understand', rather than 'see' or 'hear' camp) is the calorifier but you now remind me it has been mentioned before, probably around my first questions around the pumped water system and pressures etc.

 

So, that (the presence of a calorifier and hence the need of a PRV) sort of determines the upper pressure limit in these pumped water systems and so answerers many of my questions around this field (thanks). 😉

1 hour ago, Tony Brooks said:

 

In theory yes, but as closing an outlet has been known to produce pressure pulses in the pipework that jumps the PRV off its seat I would suggest no more than about 5 psi below PRV opening pressure, so 3 bar PRV (say 45 psi), no more than 30 PSI operating pressure. Remember, any accumulator and expansion verse may need their air pressures adjusting to suit.

Following the relayed advice from the good folk here my friend has ordered a car type footpump with built in pressure gauge, primarily to be able to monitor / adjust the pressures in this water system (secondarily to pump up the tyres on his bike). 😉 

 

Dealing with the water leak from the pump and so returning to the previous 'unnecessary pump overrun' issue is distracting us from installing the BMV-712 Smart and sorting the general wiring. 😉

1 hour ago, Alan de Enfield said:

 

I have found the regular (annually) servicing and de-scaling of taps and shower heads is more important than the pump pressure.

 

The build up of fluff / muck / rust / lime scale in the tiny filter inside the tap spouts, and the shower head holes is amazing. 

Cleaning the shower head can result in going  from a 'dribble' to (almost) a power-shower.

That's more good advice and another question / point I can relay to my friend. 😉

 

I notice that many of these pumps now come with an in-line input filter and I can't remember seeing one on my mates setup. One seems like a good idea, especially if some small foreign object could puncture the diaphragm.

 

That reminds me of the time we were bundling along in my Ex Ambulance Bedford CF Campervan when it spluttered to a halt. I diagnosed a fuel issue (overfueling) and in spite of having a fair range of tools onboard, none of them was able to undo the metal fuel union to the carb or remove the top of the float bowl. Luckily I carry a Leatherman Multitool that was able to allow me to remove the float bowl and find the small piece of swarf in the float jet. The Mrs was both amazed that 1) such a small thing could stop such a large thing and 2) that it was only my Leatherman that got us out of trouble. 😉

 

 

[RMK]

More electric.

 

I suppose we're all going to have to look seriously at electric.

[Alan de Enfield]

5 minutes ago, RMK said:

I suppose we're all going to have to look seriously at electric.

 

 

In which case someone (C&RT ?) are going to have to make some serious investment in charging infrastruture.

[David Mack]

1 hour ago, T_i_m said:

One thing I've not touched, or even seen on the Nb so far (and I'm from that 'what you do you understand', rather than 'see' or 'hear' camp) is the calorifier but you now remind me it has been mentioned before, probably around my first questions around the pumped water system and pressures etc.

If there isn't a calorifier in the boat, then does it have an instantaneous water heater - usually gas powered? If not where does the hot water come from?

[Tony Brooks]

1 hour ago, T_i_m said:

I notice that many of these pumps now come with an in-line input filter and I can't remember seeing one on my mates setup. One seems like a good idea, especially if some small foreign object could puncture the diaphragm.

 

Arguably more likely to jamb some valves open, so pressure leaks back into the water tank - hence the pump keeps turning itself on and off when no water is being drawn.

 

Edited to add: Or block/partially block the drilling that allows pressure into the pressure switch diaphragm chamber.

Edited October 2 by Tony Brooks

[T_i_m]

4 minutes ago, RMK said:

More electric.

 

I suppose we're all going to have to look seriously at electric.

I have always considered that an electrically propelled narrow boat be the optimal use for electric propulsion.

 

eg, Unlike a vehicle you aren't so worried about weight (in fact you need ballast), you have a long roof for solar panels, you aren't trying to go from 0-5 (let alone 60 mph) in 3 seconds, you therefore only putting a low load on the battery for propulsion (Peukert's law), you are generally moored up overnight for a shore charge etc.

 

I did actually get chance to speak to the owner of an EV/Nb at the local Canal Festival a couple of years back and I believe he was fairly happy with the electric propulsion bit but had more or less abandoned the use of solar energy to charge the traction batteries?

34 minutes ago, David Mack said:

If there isn't a calorifier in the boat, then does it have an instantaneous water heater - usually gas powered? If not where does the hot water come from?

Sorry David, I didn't mean to suggest there wasn't a calorifier and I believe there is one (I asked him), just that as yet I hadn't come in contact with it myself yet.

[RMK]

6 minutes ago, T_i_m said:

I have always considered that an electrically propelled narrow boat be the optimal use for electric propulsion.

 

eg, Unlike a vehicle you aren't so worried about weight (in fact you need ballast), you have a long roof for solar panels, you aren't trying to go from 0-5 (let alone 60 mph) in 3 seconds, you therefore only putting a low load on the battery for propulsion (Peukert's law), you are generally moored up overnight for a shore charge etc.

 

I did actually get chance to speak to the owner of an EV/Nb at the local Canal Festival a couple of years back and I believe he was fairly happy with the electric propulsion bit but had more or less abandoned the use of solar energy to charge the traction batteries?

Sorry David, I didn't mean to suggest there wasn't a calorifier and I believe there is one (I asked him), just that as yet I hadn't come in contact with it myself yet.

Do you think solar can produce enough to power, lets say, 4hr cruise ?

 

Electric is the way things are moving so nothing against that. Only thing is keeping things charged up..

[Tony Brooks]

38 minutes ago, T_i_m said:

I have always considered that an electrically propelled narrow boat be the optimal use for electric propulsion.

 

eg, Unlike a vehicle you aren't so worried about weight (in fact you need ballast), you have a long roof for solar panels, you aren't trying to go from 0-5 (let alone 60 mph) in 3 seconds, you therefore only putting a low load on the battery for propulsion (Peukert's law), you are generally moored up overnight for a shore charge etc.

 

I did actually get chance to speak to the owner of an EV/Nb at the local Canal Festival a couple of years back and I believe he was fairly happy with the electric propulsion bit but had more or less abandoned the use of solar energy to charge the traction batteries?

Sorry David, I didn't mean to suggest there wasn't a calorifier and I believe there is one (I asked him), just that as yet I hadn't come in contact with it myself yet.

 

As an electric narrowboat built today is almost certainly going to use lithium batteries, I suspect Peukert's law will not apply in a significant way.

30 minutes ago, RMK said:

Do you think solar can produce enough to power, lets say, 4hr cruise ?

 

Electric is the way things are moving so nothing against that. Only thing is keeping things charged up..

 

Which is why lithium batteries will be the most appropriate. They will take as much charge for as long as the solar panels can send to them. I think @IanD and @peterboat has proved that solar will provide enough charge, but perhaps at a limited speed.

 

Edited to add: during the summer - no chance in winter.

Edited October 2 by Tony Brooks

[RMK]

24 minutes ago, Tony Brooks said:

 

As an electric narrowboat built today is almost certainly going to use lithium batteries, I suspect Peukert's law will not apply in a significant way.

 

Which is why lithium batteries will be the most appropriate. They will take as much charge for as long as the solar panels can send to them. I think @IanD and @peterboat has proved that solar will provide enough charge, but perhaps at a limited speed.

Must be very peaceful cruising along with more or less no sound, other than the surroundings.

[IanD]

3 hours ago, Tony Brooks said:

 

As an electric narrowboat built today is almost certainly going to use lithium batteries, I suspect Peukert's law will not apply in a significant way.

 

Which is why lithium batteries will be the most appropriate. They will take as much charge for as long as the solar panels can send to them. I think @IanD and @peterboat has proved that solar will provide enough charge, but perhaps at a limited speed.

 

Edited to add: during the summer - no chance in winter.

 

The issue is how long, how fast and how often you cruise. If I started with full batteries (35kWh) and ran them right down I could typically cruise (and it seems I go a bit faster than many electric boats...) for more than 25 miles (measured average use is 1.3kWh/mile) without recharging, it doesn't matter whether this is all in one long day or over several shorter days -- but then the energy has to be put back.

 

How long this takes with solar depends on the time and year and whether you're moored in a sunny spot or cruising with moorings in shaded spots some of the time. I would expect my panels (2.1kW flat-mounted) to average about 7kWh/day in summer (or up to 10kWh on a sunny day) when moored in the sun, but have found that over several weeks of cruising and mooring in various places -- some in the sun, some in the shade -- I only saw about 4kWh/day on average when cruising in summer this year (2x rated panel power), about 60% of the "official" estimate.

 

This reduction is rarely considered when boaters estimate solar panel yield, but the reduction is real if you're actually moving about, and would mean only about 3 miles per day if I cruised every day on solar power alone. If you went slower then the distance would be correspondingly longer -- some boaters have claimed to use less than 1kW (which would mean going pretty slowly all the time, at "passing moored boats" speed) and that would give something like 5 miles per day (average) on 4kWh/day (average). Or a lot more on a perfect sunny day on an open canal or river with no shade, should this ever happen... 😉 

 

Note that these are all real measured power levels and solar yield, not best-case or cherry-picked numbers. And this ignores domestic power use, which again is very dependent on what you have on the boat (e.g. electric cooking, washing machine, TV, laptop) and how much you use them -- my boat is gas-free (and has all the above, and a washer-drier) and I've seen an average domestic use of 3.7kWh/day -- but ranging from 2kWh/day (very little cooking or TV, no washing) to 6kWh/day (lots of cooking and TV and washing). Other boaters with less electrical stuff will undoubtedly use less...

 

Since that domestic use is about 90% of the average solar yield when cruising, the conclusion -- at least, for me -- should be obvious... 😞 

 

And in winter the solar yield will be a lot lower, though with less reduction from shading -- the lowest I saw on a trip in mid-October was 1.9kWh/day (90% of the predicted 2.1kWh/day), compared to 4kWh/day (60% of predicted 7kWh/day) for tips in June and July. That's just enough to keep up with the lowest domestic use I ever saw, assuming not moving the boat at all... 😉 

 

Over multiple trips spread over the last year -- averaging 5 hours per day cruising at an average (including locks and passing boats) of 1.8mph, so 9 miles per day -- solar power has provided about 20% of my total energy use (generator 80%) -- the best trip (a week in June) was 33%/67%. Travelling fewer hours per day or more slowly (or better weather!) would obviously improve this... 🙂 

Edited October 2 by IanD

[T_i_m]

8 hours ago, Tony Brooks said:

 

Arguably more likely to jamb some valves open, so pressure leaks back into the water tank - hence the pump keeps turning itself on and off when no water is being drawn.

 

Edited to add: Or block/partially block the drilling that allows pressure into the pressure switch diaphragm chamber.

So, I managed to get some time on the boat this evening and ended up stripping the pump down (fully), we cleaned it up and put it together again but I wasn't convinced it was going to affect it's leaking as I felt it was likely that the diaphragm was fairly hard and so not sealing where it should (or had a split that I couldn't see).

 

We then went to check the pressure in the expansion vessel with the new foot pump I'd borrowed from daughter on the way only to find the gauge didn't work (Of course).

 

However, after the clean-up and adding 'some' pressure it seems to work to their satisfaction (quieter and doesn't over-run for as long).

 

So, given the motor is fine and the pump actually works I'd be interested to see if I can find a service it for it to cure the leak and if it doesn't with just that, I'm sure some CT-1 would seal it. 😉

 

He does have a small / spare pump to tide him over if needed.

8 hours ago, RMK said:

Do you think solar can produce enough to power, lets say, 4hr cruise ?

 

Electric is the way things are moving so nothing against that. Only thing is keeping things charged up..

Q1. Yes (given the right conditions).

 

Agreed.

 

FWIW I hired a day boat in Norfolk a good few years ago now and I think they said they only needed to charge it once every 3 days if it was out 8 hours a day?

[BoatinglifeupNorth]

9 hours ago, RMK said:

More electric.

 

I suppose we're all going to have to look seriously at electric.

 I wouldn’t look at these guys work, one of the most ugliest boat interior’s I’ve seen. Looks like they got a job lot of cheap softwood floorboards and made everything out of them, floor, walls, ceiling, cupboards, very cheap looking interior 😂

[T_i_m]

8 hours ago, Tony Brooks said:

 

As an electric narrowboat built today is almost certainly going to use lithium batteries, I suspect Peukert's law will not apply in a significant way.

 

Which is why lithium batteries will be the most appropriate. They will take as much charge for as long as the solar panels can send to them. I think @IanD and @peterboat has proved that solar will provide enough charge, but perhaps at a limited speed.

 

Edited to add: during the summer - no chance in winter.

Agreed on the last point (in the UK) but I'm not sure why you would have to go lithium given the weight of LA isn't an issue for a Nb and also LA is nearly 100% recyclable and so far 'greener' than Lithium?

[IanD]

7 minutes ago, T_i_m said:

Agreed on the last point (in the UK) but I'm not sure why you would have to go lithium given the weight of LA isn't an issue for a Nb and also LA is nearly 100% recyclable and so far 'greener' than Lithium?

Because LA batteries have low efficiency (what you get out compared to what you put in), need many hours of low-current charging to get them up to 100% SoC regularly to prevent sulphation, don't like being regularly discharged to below 50% SoC, and have maybe 10x shorter lifetime than LFP.

[T_i_m]

5 hours ago, IanD said:

 

The issue is how long, how fast and how often you cruise. If I started with full batteries (35kWh) and ran them right down I could typically cruise (and it seems I go a bit faster than many electric boats...) for more than 25 miles (measured average use is 1.3kWh/mile) without recharging, it doesn't matter whether this is all in one long day or over several shorter days -- but then the energy has to be put back.

 

How long this takes with solar depends on the time and year and whether you're moored in a sunny spot or cruising with moorings in shaded spots some of the time. I would expect my panels (2.1kW flat-mounted) to average about 7kWh/day in summer (or up to 10kWh on a sunny day) when moored in the sun, but have found that over several weeks of cruising and mooring in various places -- some in the sun, some in the shade -- I only saw about 4kWh/day on average when cruising in summer this year (2x rated panel power), about 60% of the "official" estimate.

 

This reduction is rarely considered when boaters estimate solar panel yield, but the reduction is real if you're actually moving about, and would mean only about 3 miles per day if I cruised every day on solar power alone. If you went slower then the distance would be correspondingly longer -- some boaters have claimed to use less than 1kW (which would mean going pretty slowly all the time, at "passing moored boats" speed) and that would give something like 5 miles per day (average) on 4kWh/day (average). Or a lot more on a perfect sunny day on an open canal or river with no shade, should this ever happen... 😉 

 

Note that these are all real measured power levels and solar yield, not best-case or cherry-picked numbers. And this ignores domestic power use, which again is very dependent on what you have on the boat (e.g. electric cooking, washing machine, TV, laptop) and how much you use them -- my boat is gas-free (and has all the above, and a washer-drier) and I've seen an average domestic use of 3.7kWh/day -- but ranging from 2kWh/day (very little cooking or TV, no washing) to 6kWh/day (lots of cooking and TV and washing). Other boaters with less electrical stuff will undoubtedly use less...

 

Since that domestic use is about 90% of the average solar yield when cruising, the conclusion -- at least, for me -- should be obvious... 😞 

 

And in winter the solar yield will be a lot lower, though with less reduction from shading -- the lowest I saw on a trip in mid-October was 1.9kWh/day (90% of the predicted 2.1kWh/day), compared to 4kWh/day (60% of predicted 7kWh/day) for tips in June and July. That's just enough to keep up with the lowest domestic use I ever saw, assuming not moving the boat at all... 😉 

 

Over multiple trips spread over the last year -- averaging 5 hours per day cruising at an average (including locks and passing boats) of 1.8mph, so 9 miles per day -- solar power has provided about 20% of my total energy use (generator 80%) -- the best trip (a week in June) was 33%/67%. Travelling fewer hours per day or more slowly (or better weather!) would obviously improve this... 🙂 

Interesting numbers, thanks.

 

I wonder how much any of that could be improved by designing a Nb with high efficiency in mind?

 

Like, I'm sure many here would be aware of Cedric Lynch, the inventor of the Lynch Motor who took a very new a motor design and came up with something that couldn't be beaten by any commercial offering (at the time or that we could afford when racing against him at the time). 😉

 

So, when he was 'electrifying' an outboard he was aware that oil seals caused a lot of drag in the underwater bevel gears and so he replaced the metal bevel gears (or one gear) with some 'plastic' ones that could be lubricated with water and so he could do away with some of the energy sapping components. So I believe his 'Solar Canoe' won some record for distance travelled purely by solar power or some such?

 

So what I think we often do is try to electrify some existing solution but also try to retain all the 'mod cons' or design because that's all people know / want.

 

By that I mean insisting that a car has to be an extension of your lounge and be able to have different temperatures in each side of the same space!

7 minutes ago, IanD said:

Because LA batteries have low efficiency (what you get out compared to what you put in), need many hours of low-current charging to get them up to 100% SoC regularly to prevent sulphation, don't like being regularly discharged to below 50% SoC, and have maybe 10x shorter lifetime than LFP.

But ignoring any self discharge or efficiency issues for a moment and assuming the ability to charge using green energy, just how green / sustainable are Li compared with LA?

 

I mean, it seemed to work for milk floats for many years / miles *because* the use in a Milk Float (/ fork lift / pallet truck / golf buggy) was fairly well matched with that chemistry and / or you matched the use with the energy available?

[Tony Brooks]

The problem with narrowboats is that the roof area limits the amount f solar you can easily install, that limits the amount of electricity they can generate. This means that to maximise range (and domestic use) every scarp of that electricity needs to e stored and not wasted. When you get the battery monitor working properly, you will see that in less than an hour of engine running, the charging current starts to drop. Not because the alternator can't maintain the charge, but because lead acid batteries start to refuse to accept any more current. The drop in charging current continues for many hours, until eventually (maybe 8 to 10 hours or more) it stabilises at a few amps. Then the batteries are as fully charged as you can get them. So for the vast majority of the time, the amount of the available charge is refused by the LA batteries. As an example, over about the first 3 hours the average charge is about 50% of what the charge source can provide. The for each further hour, the average drops lower and lower. The fact it takes so long to fully charge LA batteries is why so many boaters ruin then by consistent undercharging. It won't matter how efficient you make the motor and control gear, you will never overcome this drop in charging current with a LA bank.

 

Lithium batteries are different, from discharged to fully charged they will accept as much current as the charge source can supply, so they take all the solar charge for as long as it is available. That makes a huge difference in how fully solar can charge the bank.

 

On the green score, I doubt LA batteries could be endlessly recycled in the early years of the last century but gradually the facilities and procedures became available, I think the same will happen with lithium over the coming years.

[Jon57]

27 minutes ago, Tony Brooks said:

The problem with narrowboats is that the roof area limits the amount f solar you can easily install, that limits the amount of electricity they can generate. This means that to maximise range (and domestic use) every scarp of that electricity needs to e stored and not wasted. When you get the battery monitor working properly, you will see that in less than an hour of engine running, the charging current starts to drop. Not because the alternator can't maintain the charge, but because lead acid batteries start to refuse to accept any more current. The drop in charging current continues for many hours, until eventually (maybe 8 to 10 hours or more) it stabilises at a few amps. Then the batteries are as fully charged as you can get them. So for the vast majority of the time, the amount of the available charge is refused by the LA batteries. As an example, over about the first 3 hours the average charge is about 50% of what the charge source can provide. The for each further hour, the average drops lower and lower. The fact it takes so long to fully charge LA batteries is why so many boaters ruin then by consistent undercharging. It won't matter how efficient you make the motor and control gear, you will never overcome this drop in charging current with a LA bank.

 

Lithium batteries are different, from discharged to fully charged they will accept as much current as the charge source can supply, so they take all the solar charge for as long as it is available. That makes a huge difference in how fully solar can charge the bank.

 

On the green score, I doubt LA batteries could be endlessly recycled in the early years of the last century but gradually the facilities and procedures became available, I think the same will happen with lithium over the coming years.

Even trying to go green is expensive. https://www.theguardian.com/business/2024/oct/01/sweden-fears-for-future-of-batterymaker-northvolt

[T_i_m]

51 minutes ago, Tony Brooks said:

The problem with narrowboats is that the roof area limits the amount f solar you can easily install, that limits the amount of electricity they can generate. This means that to maximise range (and domestic use) every scarp of that electricity needs to e stored and not wasted. When you get the battery monitor working properly, you will see that in less than an hour of engine running, the charging current starts to drop. Not because the alternator can't maintain the charge, but because lead acid batteries start to refuse to accept any more current. The drop in charging current continues for many hours, until eventually (maybe 8 to 10 hours or more) it stabilises at a few amps. Then the batteries are as fully charged as you can get them. So for the vast majority of the time, the amount of the available charge is refused by the LA batteries. As an example, over about the first 3 hours the average charge is about 50% of what the charge source can provide. The for each further hour, the average drops lower and lower. The fact it takes so long to fully charge LA batteries is why so many boaters ruin then by consistent undercharging. It won't matter how efficient you make the motor and control gear, you will never overcome this drop in charging current with a LA bank.

 

Lithium batteries are different, from discharged to fully charged they will accept as much current as the charge source can supply, so they take all the solar charge for as long as it is available. That makes a huge difference in how fully solar can charge the bank.

 

On the green score, I doubt LA batteries could be endlessly recycled in the early years of the last century but gradually the facilities and procedures became available, I think the same will happen with lithium over the coming years.

Interesting points Tony but possibly only 'an issue' if you try to work around the issues of LA (compared with say Lithium) rather than working with them and using them as we have so far?

 

Like, I wasn't suggesting that you ran entirely on Solar but that 1) it should be considered 'a bonus', as when it's available ... or even be focussed on the domestic proportion / component of the battery.

 

It's also possible that the solar array be more efficient, self erecting and tracking so to make the best use of the panels where circumstances allow (like when moored beam on to the general sun path).

 

There could also be mooring provision for such boats, just as there currently are for parent & child parking where there is no shade etc.

 

2) The LA battery would be very large, especially given the load carrying capacity of these boats. Possibly large enough to allow you to cruise for a week between charges. This may require a different approach to their construction with a false / (reasonably) accessible floor to a keel level and fully ventilated 'battery hold'. The batteries would be sealed 'recombination' vent type, or even gel etc. Again, with a big enough bank the load would be very low and so well up the discharge efficiency chart.

 

3) Because the battery was so large, you wouldn't need to worry about it being fully charge every charge cycle and you wouldn't therefore have to worry about about over-discharge and cycle life. This is like us only using the car infrequently and so a 'full tank' sometimes lasting us a couple of months.

 

4) The focus for these sort of EB's would be those who may be mainly - 'Live aboard' / free mooring where the propulsion side / use of the battery would only need to cover the fortnightly move (potentially allowing plenty of time for a solar top-up / shore / generator charge). This is like focussing the use as you might for a second / shopping EV or any of the millions of LA powered utility vehicles who run an 8 hour shift and then put on charge overnight or every so often.

 

When I designed, built and raced (endurance rather than speed) my electric motorcycle, I ran the same battery as most people (25kg of LA) and was limited to the best (efficiency) commercially available electric motor I could find / afford. Cedric Linch, running the same capacity battery but his home made battery could probably do twice the laps the rest of us could OR, was far less likely to be putting his battery under anywhere near the stress we were (where we nearly treated them as consumable).

 

Re recycling, I understand lead (inc from LA batteries) is one of the most completely recycled metals and always has been.

"Lead batteries reign as the most recycled consumer product in the U.S. today and the most sustainable battery technology; 99% of lead batteries are safely recycled in an established, coast-to-coast network of advanced recycling facilities."

 

I'm not sure how that compares with Lithium but why would we want to compete with that (EV etc) market when the usage is (or could be) completely different?

 

Just interested minds, thinking out loud. 😉

1 hour ago, Jon57 said:

Even trying to go green is expensive. https://www.theguardian.com/business/2024/oct/01/sweden-fears-for-future-of-batterymaker-northvolt

And yet LA has been used for propulsion for over 100 years and LA are still used for all sorts of things.

 

Part of that is the simplicity and so robustness of them as a solution. No individual cell BMS, no need to heat or cool (if the river is frozen the chances are you aren't going anywhere <G>) fairly simple chargers can be used, little retraining for service personnel etc etc.

 

Even my EV (8 x 6V LA) that only had a range of 20 miles and a top speed of 30 mph would take me to work and back for a couple of weeks on one change (50p at the time). The point being it was being used in a way appropriate to it's abilities.  Many people insist on driving a car that is capable of 100 mph whilst living and driving in London where the average speed is 11 mph?

[nicknorman]

40 minutes ago, T_i_m said:

Interesting points Tony but possibly only 'an issue' if you try to work around the issues of LA (compared with say Lithium) rather than working with them and using them as we have so far?

 

Like, I wasn't suggesting that you ran entirely on Solar but that 1) it should be considered 'a bonus', as when it's available ... or even be focussed on the domestic proportion / component of the battery.

 

It's also possible that the solar array be more efficient, self erecting and tracking so to make the best use of the panels where circumstances allow (like when moored beam on to the general sun path).

 

There could also be mooring provision for such boats, just as there currently are for parent & child parking where there is no shade etc.

 

2) The LA battery would be very large, especially given the load carrying capacity of these boats. Possibly large enough to allow you to cruise for a week between charges. This may require a different approach to their construction with a false / (reasonably) accessible floor to a keel level and fully ventilated 'battery hold'. The batteries would be sealed 'recombination' vent type, or even gel etc. Again, with a big enough bank the load would be very low and so well up the discharge efficiency chart.

 

3) Because the battery was so large, you wouldn't need to worry about it being fully charge every charge cycle and you wouldn't therefore have to worry about about over-discharge and cycle life. This is like us only using the car infrequently and so a 'full tank' sometimes lasting us a couple of months.

 

4) The focus for these sort of EB's would be those who may be mainly - 'Live aboard' / free mooring where the propulsion side / use of the battery would only need to cover the fortnightly move (potentially allowing plenty of time for a solar top-up / shore / generator charge). This is like focussing the use as you might for a second / shopping EV or any of the millions of LA powered utility vehicles who run an 8 hour shift and then put on charge overnight or every so often.

 

When I designed, built and raced (endurance rather than speed) my electric motorcycle, I ran the same battery as most people (25kg of LA) and was limited to the best (efficiency) commercially available electric motor I could find / afford. Cedric Linch, running the same capacity battery but his home made battery could probably do twice the laps the rest of us could OR, was far less likely to be putting his battery under anywhere near the stress we were (where we nearly treated them as consumable).

 

Re recycling, I understand lead (inc from LA batteries) is one of the most completely recycled metals and always has been.

"Lead batteries reign as the most recycled consumer product in the U.S. today and the most sustainable battery technology; 99% of lead batteries are safely recycled in an established, coast-to-coast network of advanced recycling facilities."

 

I'm not sure how that compares with Lithium but why would we want to compete with that (EV etc) market when the usage is (or could be) completely different?

 

Just interested minds, thinking out loud. 😉

And yet LA has been used for propulsion for over 100 years and LA are still used for all sorts of things.

 

Part of that is the simplicity and so robustness of them as a solution. No individual cell BMS, no need to heat or cool (if the river is frozen the chances are you aren't going anywhere <G>) fairly simple chargers can be used, little retraining for service personnel etc etc.

 

Even my EV (8 x 6V LA) that only had a range of 20 miles and a top speed of 30 mph would take me to work and back for a couple of weeks on one change (50p at the time). The point being it was being used in a way appropriate to it's abilities.  Many people insist on driving a car that is capable of 100 mph whilst living and driving in London where the average speed is 11 mph?

Couple of things, firstly LA batteries don’t like being left for long periods below 100% SoC

 

But the main point is energy efficiency. LA has a charge efficiency (charge as in the integral of current) of around 94% vs 99% for Li. But that is only part of the story. Because the voltage difference between charging and discharging is quite high for LA (say 14.4 and 12.5) vs Li (say 13.6 vs 13.2) the “voltage efficiency” is 86% vs 97%. So the energy or power efficiency, being the multiple of charge and voltage efficiency, is around 80% for LA and 96% for Li. So 16% of energy is wasted by using LA vs Li.