IanD
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Posts posted by IanD
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15 minutes ago, magnetman said:
I have endless room in my head for batteries.
I suppose people do have space constraints which is why the drop in thing exists in the first place.
One day these problems will be solved when infernal combustion engines are banned.
See above
Its an interesting question.
i wonder if it is good for the makers (lets say Victron) to keep these two products separate in order to shift more blue items in flash boxes. They might be electronically very similar. I don't know but have difficulty working out why the output from an alternator through a battery would be so different from a solar panel.
A solar panel acts as a light-dependent current source, but at high voltages the current drops off -- as some point the product of V*I is maximum power, and the MPPT controller tries to find this by changing its own input voltage up and down periodically to track this point, or to be more accurate by adjusting the gain between input and output. It can only step voltage down so Vin has to be bigger than Vout. It's not expecting the input to be a low impedance voltage source like a battery, it's expecting it to be a solar panel with very different characteristics.
A DC-DC B2B converter is designed to work with low impedances (voltage sources) on both sides and control the current between them, and works when the input is lower or higher than the output.
They're fundamentally different beasts that work in different ways, have different internal circuits (buck vs. buck-boost SMPS if you want to get technical), and different control and protection algorithms.
The only thing they have in common is they both come in blue boxes... 😉
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10 minutes ago, Sue Taylor said:
Yes true but we really want to do the tardebigge in whatever capacity ! Didn't think it could be possible in the first day.... My brother is a bit tentative me and my son etc just want to get on with it 🤣
100% possible in the first day on a hire boat from Anglo-Welsh at Tardebigge... 🙂
To speed things up you need to get a system going at the locks, sending one person ahead to get the next one ready, ideally having two working the lock the boat is in, with one leaving when the boat does and the other staying behind to close up. That way there's no waiting, and if there aren't any other boats in the way you leave one lock and motor straight into the next one which is waiting ready. Slicker than a time traveling con artist that goes back in time to steal a submarine and mate with a whale swimming in olive oil... 😉
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1 minute ago, magnetman said:
24v Alternator 55A is £150 (prestolite lucas a127)
Couple of cheap lead acid batteries £150.
I already have a 50A MPPT which is surplus in winter.
50A b2b would be £300.
It costs the same. I think the 24v alternator might be better for thermal management as there are less amps coming out of it.
If you've got the space for 4 sets of batteries (12V starter, 2x12V LA, 12V LFP) and think the (surplus?) "free" MPPT will work as a B2B (only in winter?), go ahead, it's your boat.
For most people it doesn't seem like a good solution though... 😉
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4 minutes ago, magnetman said:
The Boat domestic system is run by a 12 (13) volt LFP bank.
The only 24 volt parts would be the alternator and the small Lead battery bank. This would be routed via the MPPT (might not work) to the LFP battery bank which would be 12/13v.
But what's the point? Do you have 12V (starter) *and* 24V (domestic) LA batteries as well as a 12V domestic LFP? Do you have 12V and 24V alternators?
Why do all this when a B2B (or alternator regulator) is simpler, probably cheaper, and less to change?
The simplest (and cheapest?) solution is probably to keep the 12V starter battery and alternator, swap the 12V domestic LA bank for LFP, and add an alternator regulator to the 12V domestic alternator to charge the LFP bank. Alternatively, keep the existing alternators and LA batteries and add a B2B and LFP for domestic power.
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Just now, Sue Taylor said:
Ok thanks for the information ! I have been told about the severn liable to flood .... fingers crossed.
Well we're pretty sure that we would /could do in a week weather and water permitting, as we're all quite fit and able.......
Both Avon and Stourport rings are great weeks for a keen/fit crew who like long days and locks, lovely canals and rivers with some excellent stopping places. Always worth having a contingency plan though, especially on rivers... 😉
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1 minute ago, magnetman said:
The system I was referring to has dual alternators. The starter would be 12v.
You seem to be trying to make a silk purse out of a sow's ear -- if you're going to start replacing alternators and adding a B2B, it's probably cheaper (and better!) to add an alternator regulator like the Wakespeed which can also sense alternator temperature and cut back current at low rpm and lots of other things.
If you're starting from scratch then 24V makes a lot of sense, but changing to this adds even more cost (lights, pumps etc...).
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8 minutes ago, Rob-M said:
Keep an eye on the weather in the weeks before you are going in case the Severn and\or Avon could go in to flood and prevent you doing the ring.
When I was 16 I took a group of Japanese students around the Avon ring from Alvechurch in a one week hire, as they didn't speak much English it was hard work.
If the rivers are high then the Stourport Ring may be easier than the Avon ring. Or not. Or both might be impassible...
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1 minute ago, Tony1 said:
I wish I could give you a proper answer!
What I did was to cut various lengths of cable, and did a bit of trial and error till I had a set of different cable lengths that would limit the output current from the alternators 30 amps, 35 amps, 40 amps, and 45 amps, and I think 50 amps.
I wired those in and ran the engine at idle, and used one of those thermometers that you point at things to measure the alternator temp (measuring the hottest spot, as the temp does vary around the casing).
In my case I found that if the alternator was putting out more than 35 amps at idle it would get hotter than 100 degrees, so I bought the B2Bs with that limitation in mind.
I did also measure how the alternators behaved at 1300 rpm, and found that I could suck more current from them at that speed, but you can only guarantee doing that rpm when sat on a mooring doing a 'static' charge.
So you could set a lower limit for the general case, and turn it up when charging at 1300rpm when moored... 🙂
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8 minutes ago, Tony1 said:
I follow that principle when engine charging- I usually charge at about 1100 rpm or bit more, after a couple of mins at idle to let things warm a little bit.
The scenario I have in mind is when cruising and you're going past a long line of boats at tickover, or going trough a lock, say- those times when you're engine is at idle for periods of time. Thats the sort of 'worst case' I had in mind when selecting the correct size of B2B to suit your alternator.
If you're worried about that case, B2Bs like the Victron have programmable current limits (phone app via Bluetooth, dead easy to adjust).
4 minutes ago, magnetman said:Maybe A 24v alternator, 2 LA batteries to make a 24v bank and the MPPT repurposed for winter to charge the LFP batteries via alternator. In summer the solar does the job and the other alternator is still 12 volts.
But the engine needs a 12V start battery, and has a 12V alternator...
I'm not sure using an MPPT controller as a B2B is a good idea, the nature of the beast is different -- an MPPT controller is expecting to have solar panels on the input, and to adapt the input current and voltage to maximise output power from the panels. Not sure how this will react when the input side is an LA battery being charged by an alternator, maybe it'll just provide maximum output current all the time...
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7 minutes ago, Sue Taylor said:
All that could be interesting I may contact them and tell them that's what we're planning and see what they say..
. Did you contact the boatyard or anglo welsh directly
Thanks for your help so far sorry I saw that you said anglo welsh
IIRC I rang Anglo-Welsh at Tardebigge directly (0117 304 1122).
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7 minutes ago, Tony1 said:
I currently use two LA batteries- one for each alternator. So each LA then 'feeds' into its own B2B unit.
I did try running both alternators through a single LA battery to start with, but one of them runs at about 0.5v higher than the other. What seems to happen is that when they run in parallel to a single LA, the alternator running at the lower voltage fails to operate fully, and only puts out maybe 10-15 amps at best. But when running into separate LAs, they both run properly.
I originally tried pulling more current from the domestic alternator but it just got too hot. Revving the engine to 1300 helps to cool the alternators, and I can squeeze out maybe 90 amps safely at 1300 rpm from both alternators, but it feels like I'm asking a lot of the crank and the belts doing that.
So a 50 amp unit wouldn't really help me.
I do think that before buying anything, people considering B2Bs need to test out their alternator(s) capability in the worst case scenario for alternator temp (i.e. sucking max current out when running at idle).
Because if you buy a 50 amp B2B and your alternator can only put out 35 amps like mine, you've wasted your money, because cant use the 50 amp B2B at all (although some can be set to run at half power, e.g. the Sterlings).
Completely agree -- but then it's usually recommended to run above idle (>1200rpm) for battery charging, it uses less fuel and charges the batteries faster and the alternators don't get so hot, they really don't like their cooling fans turning slowly while putting lots of current out. Some people have also added cooling fans and ducting to blow cold air from outside the engine bay into the alternators to stop them overheating.
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12 minutes ago, Sue Taylor said:
Well that sounds good it could be doable if we leave early enough. Although we are going Easter Saturday so I'm not sure how busy it will be 😬
Easter Saturday start date !
Anglo-Welsh were helpful, we told them in advance that we were planning to go down Tardebigge (and were experienced so didn't need a long handover) and they helped us get away relatively early, about 2pm IIRC.
We did come up behind a slower boat so it took us about 4 hours, it would have taken 3 hours otherwise... 😉
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2 minutes ago, Tony1 said:
Those are the ideal solutions, no doubt about that, but so expensive...
My thinking was that the market could do with having a unit that could be cabled in by an average boater (like an MPPT or a B2B can).
As magnetman says, the MPPTs seem to be tantalisingly close to being able to do the job...
MPPTs need the input voltage to be several volts higher than the output, so you can't use then for connecting alternator + 12V LA to 12V LFP.
B2Bs do the job required but decent higher-current ones aren't cheap, the 50A Victron one (looks perfect for the job) is about £300... 😞
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15 minutes ago, Tony1 said:
I can say the B2B units get very hot in use, so there's certainly a lot of heat energy wasted, although I've not measured the current going into them, only that coming out- so I cant say for sure. The previous Sterling unit I used seemed to waster at least 15% of the input current as heat.
My starter and domestic alternators are rated at 70 amps and 100 amps respectively, but they cant keep that up without overheating.
To keep their temp below 100 degrees, I can't take more than about 30 and 35 amps from them respectively, so the victron units are a pretty good match for their safe current output level. So I get about 60amps into the lithiums in total.
I did also install a third smaller B2B, with 18 amps output. I sometimes use the third B2B when I'm doing a static charge, because when doing that I can keep the revs up at 1300 rpm, which helps cool the alternators. So flat out I can get almost 80 amps of charge, but I don't always use the third B2B.
Mine is a canaline 38 and it has narrow V belts- not poly V- and I feel like I might be straining the belts and the crank more I should when I do a 90 minute battery charge at the full 80 amps. So I tend to stick to using two B2Bs for most of the time.
I cant remember the max charge of the lithiums, but its certainly much more than I ever do to them! Even when cruising in high summer, with maybe a further 90 amps of solar coming in for long periods of the day, the charge current is only around 150 amps max.
Tbh in those high solar months, I tend to leave the B2Bs switched off for most of the time, even when the engine is running, since the solar does everything I need and more.
(Speaking of which, I've had 1100 Wh of solar today, so I feel like we may be starting to get into the period where it gets useful again)
Are you planning to keep the LA domestic battery or just have LA starter + domestic LFP + B2B? In which case you'd connect both alternators in parallel to the LA (if this works...) and have a bigger B2B for charging the LFP
35A continuous out of your 100A domestic alternator sounds pretty poor, most people seem to be OK with maybe 50% current even when charging LFP banks. I'd have thought something like a Victron Orion XS 12V-12V 50A battery charger would do the job nicely -- programmable currents and voltages, maximum efficiency is 98.5%, I expect full-load is less than this but should still be well above 95%. About £300 though, and not out for a couple of months... 😉
https://www.victronenergy.com/dc-dc-converters/orion-xs-12-12-50a-dc-dc-battery-charger
https://offgridpower.solutions/shop/victron-energy-smart-buckboost-dc-dc-charger-non-isolated-50a
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57 minutes ago, Tracy D'arth said:
Trying to get 260A plus inverter losses out of batteries is not a good idea..............
I have found practically no marinas where you got the full 240V @13A supply to a boat. Some are only 5A
Best I found was a dairy farm where the electrics were straight off the overhead into their own transformer. You could see 256V when they were not milking cows or cooling the tanks.
The marina I'm at (Uplands) will happily supply 16A/230V (3.7kW) for several hours continuously...
(this is after the isolation transformer which has a slight step-up, so shoreline input is 230V/16A when charger sees 250V/15A)
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52 minutes ago, Tony1 said:
Obviously I'm no expert, but my hope/expectation is that placing a B2B charger between the LA and the lithium bank will resolve point 3.
I use victron 30 amp B2Bs, and my understanding is that no current can flow from the lithium back into the LAs.
The fourth issue is managed by setting a safe bulk charging voltage on the B2B, e.g. 13.8 or 13.9v.
From what I've observed, when the lithium gets up to about 90% full its voltage will start to rise above the bulk charging voltage in the B2B, and this causes the B2B to go into float mode.
If you set float voltage to something like 12.5v, it means effectively no further current will pass into the lithiums.
So maybe a B2B does provide a step up in terms of safety from a simple 'long wire' setup?
Certainly it allows more precise control of the charging that is done to the lithiums.
On the downside, as has been said here many times, B2Bs are very inefficient, and not really very a cheap solution, and who knows whether they will be deemed acceptable by potential future regulations?
A decent B2B isn't inefficient (well over 90%?), and should be accepted by future regulations since you're treating the LFP properly/safely, not connecting it in parallel with LA and charging from an alternator. Make sure the B2B does have settings suitable for charging LFP not just LA.
Not sure that 30A will be enough though if you want to minimise engine running time when charging, something that can use more of the alternator's output (without overheating it!) would be better, so long as it doesn't exceed the maximum charge current of the LFP. What size alternator do you have, and what's the LFP charge current rating?
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52 minutes ago, Sue Taylor said:
We are having a boat from tardebigge for one week and hopefully intend to do the Avon ring. What are people's thoughts on that there are four active members on board that I used to doing lots of locks and covering distance. I know the topic has been covered but should we attempt the lock flight on the first day if we get away at a reasonable hour ?
We -- also with four active lock-lovers on board -- got down Tardebigge (starting from Anglo-Welsh, which I guess you're doing?) on the first afternoon, in plenty of time for dinner at the Queen's Head.
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37 minutes ago, blackrose said:
I said it's not a useful feature for most users, not just for me.
I have a different opinion on this to you and Ian, is that ok? You think it's a useful feature, I don't. I hope different opinions are allowed. We'll just have to agree to disagree.
You do have a track record of denigrating anything high-tech -- especially if it's fitted to other people's boats but not yours -- as "silly", when it's nothing of the kind, it just happens you don't need it or it doesn't suit you -- which is perfectly fine.
And I agree that it's not useful *for you*, just like DC powering of a router. But it is useful *for others*, just like DC powering of a router.
Making a statement like "That sounds like another silly high tech feature that certain expensive electronics manufacturers add which ends up creating more trouble than it saves!" just shows you haven't really thought about it... 😉
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20 minutes ago, cheesegas said:
Routers designed for mobile use like Proroute and Teletonikas are a bit more expensive but they have wide range DC inputs, often 9v-30v meaning they can be powered straight from 12v. High end ones even have built in GPS receivers so all you need is a £10 GPS antenna and you've got a built in boat tracker.
I have a Teletonika RUTX12 on my boat with two SIMs and two 4G antennas. It balances the load across the two modems, and if one connection is too slow to respond, it'll funnel it all towards the better one automatically. Works great for most of the south east, I get 10-100mbps depending on location. Three and EE SIMs at the moment but around the Stort, O2 seems to be a better option so I might swap the Three one out.
They do but they can be a *lot* more expensive depending on what you're looking for, and also lack some useful features.
I was looking for a 5G 4x4 MIMO router, the Proroute NR550 was £570 compared to £150 for an ex-Three NR5103E. It does support dual-SIM failover (good!) but doesn't have USB file-sharing which I wanted, nor a mobile app for management/logging.
Ideally I'd have liked all the above features, but couldn't find anything that provided them -- then you have to make a choice as to what best suits you, and I went for the NR5103E on the principle that it did everything except dual-SIM and was cheap enough to replace if/when something better came along.
As usual it's horses for courses, there's no single ideal solution for everyone... 😉
5 minutes ago, blackrose said:Yes, and I never said that they were or they did.
Oh come on, stop wriggling -- you said that particular one was silly, and it's not, there is a good reason for it -- but you don't want to admit you were wrong... 😉
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9 minutes ago, magnetman said:
It would be fun if a court had to decide what 'drop in' means.
They might come to the conclusion it just means two items the same shape.
If somebody whose electrics were damaged ever sued an LFP "drop-in" battery supplier for using the term, I suspect the supplier would lose -- because the potentially damaging consequences of naive "LFP drop-in" are well known, and normally manufacturers have to warn of any known consquential risks of using their products as sold and advertised. And the courts have often found that a disclaimer in the small print of an page 37 of the user manual is not sufficient if the consequences can be severe -- in this case, hundreds of pounds worth of damage, maybe more if a load dump kills other 12V gear not just the alternator.
If it's ever going to happen, I expect it would happen first in the USA -- and shortly afterwards LFP advertising would change tone... 😉
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25 minutes ago, blackrose said:
I don't think my inverter has power save mode. The quiescent current is only 0.6A and it doesn't require a certain load to keep it working. That sounds like another silly high tech feature that certain expensive electronics manufacturers add which ends up creating more trouble than it saves!
Yes I agree with that, if that's what you're doing. I'm not though so there's no reason for me to run it from DC.
No, it's a feature which can be useful on inverter/chargers bigger than yours (for electric-heavy boats) which have higher no-load power consumption, up to 5A (60W) in some cases. It can always be turned off to stop possible AC power cuts if you don't want to use it. Some setups even allow this to be done remotely, via the DC-powered router... 😉
Not all high-tech features are silly, and not everyone has the same setup and requirements as you (or I) do... 🙂
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16 minutes ago, MtB said:
Nope. Not a word about it came with either my Renogy Drop-In or my LifeBatteries Drop-In.
Either the customers buying these things are better informed than we here think, or the manus have some rock-solid defences against people complaining their alternators have cooked or lost all their magic smoke.
But it's not their fault if you fry your alternator by loading it heavily for ages, it's yours for not keeping it cool enough or limiting the charging current. And it's not their fault if the voltage spike when it overvoltage disconnects blows up either your alternator or other stuff on the boat, they told you the BMS would do this at high voltage so it's up to you to deal with the consequences. They'll just say "We can't possibly know how you're going to use our battery, we just provide it".
Plenty of cases of killed/fried alternators, see marinehowto or any of the yachting forums... 😞
10 minutes ago, BEngo said:But it is not the alternator ( or other dumb) charging in itself that is a problem. The problem is the effect of relying on the BMS ( a battery protection device) to be a charge control device and of using an inappropriate alternator ( not able to providea suitable continuous output) as charge source.
Neither is difficult to solve safely though charge control solutions are somewhat limited options.
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Correct, but these problems don't happen with LA do they? So if you tell people that your LFP is a "drop-in" replacement so they do exactly that, whose problem is it?
Many people don't have a clue about battery chemistry or charging or alternators or BMS or charge control, they just connect something up as the suppliers suggest -- so "drop-in" means just that, nothing else is changed.
This isn't a "nanny state" thing, I'm not saying LFP batteries shouldn't be sold as modern replacements for LA -- but it's dishonest for the suppliers to use the term "drop-in" with no warnings about what the (expensive!) consequences of doing this can be in some -- not all! -- cases.
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11 minutes ago, MtB said:
I wonder how many off grid caravans there are out there, forming the main market for 'drop-in' LFPs.
My finger in the air guess is about a million. Against perhaps 30,000 liveaboard and holiday boats big enough to be charging an LFP from an engine alternator. Total guess.
By far the biggest market for "drop-in" LFP batteries -- what they were originally made for, in massive numbers at minimum cost -- are solar backup batteries mounted on lighting poles in the Far East. All that's needed here is the lowest possible price and relatively low current capability and adequate lifetime, which is exactly what some of the cheapest "drop-ins" provide with a cheap nasty internal BMS -- stick a new label on ("marine" or "heavy duty" or whatever) and get them out of the door. They're not designed to play nicely with alternators -- or high-current loads, like some on a boat -- because they don't have to for the application they were originally intended for.
https://marinehowto.com/drop-in-lifepo4-be-an-educated-consumer/
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19 minutes ago, GUMPY said:
Most of the marketing is aimed at caravans and mobile homes and not boats. In caravans and mobile homes it is pretty much drop in so not misleading.
I disagree -- if you're going to market something as "drop-in" that clearly suggests you can safely do this anywhere an LA battery is used, just "drop-in" LFP as a replacement. Which is not the case... 😞
If the sellers also attached warnings about how these may not be suitable where alternator charging -- or any other "dumb" charging -- is used then maybe this would be OK. But they don't, do they?
It's a bit like promoting a novel foodstuff as a healthier replacement without pointing out that some people are allergic to it and might die as a result, except here the potential victims are equipment not people... 😉
Don't get me wrong, I think LFPs are great when used appropriately, otherwise I wouldn't have a boat with a huge bank of them. But like any new technology there are cases when care is needed, and some suppliers are ignoring this.
Curtain and blind advise please
in Boat Equipment
Posted
I looked at using bungs on the portholes, but decided against them -- one reason being that you can't have light blocked out and still have any ventilation (opened portholes), for example in a bedroom in summer.
The roller blinds with magnetic catches solve this problem, but some may not like the looks -- or the cost, though porthole bungs still have to be made and covered.
As so often, there's no solution which suits everyone's needs and preferences, all have plus and minus points -- you just need to pick what's best for you... 😉