PaulRainbow
Well-Known Member
Was about to type exactly this.
Self install of LifePo4 and what requirements for insurance (UK)
- Thread starter davethedog
- Start date
PaulRainbow
Well-Known Member
Not entirely correct. If you get the charging wrong the BMS will block charging, loads remain on, unless you have a crap BMS.
"Dark ship" would be rare, but not nice if it happened, exactly the same as if, under certain circumstances, you lost the LA domestics. It's oh so easy to overcome though, in several different ways. In fact, all of my LA installations and upgrades are already setup to be able to overcome it within seconds. I always fit an emergency parallel switch between the load terminals of the main isolators, so all you'd need to do is turn the emergency switch on and the domestic switch off. Get yourself somewhere safe and then investigate what went wrong. In a properly installed system, short of a failed battery or BMS, the most likely thing to cause the loads to be turned off would be over discharge protection, that's user error.
It's rare to have the alternators connected to the LFPs, that would require expensive and unnecessary equipment, where a DC-DC charger would do the job, in which case, no way the alternator would be damaged. Not sure how you'll fry the electronics by turning them off. I turn mine off everytime i've finished with them, they don't seem to mind.
That's just a way to sell you more blue boxes, see Geems post.
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aqua_sax
Well-Known Member
Indeed. Why waste a good headline? To survive, a media source, which these days covers a lot more than the press, has to be more interesting than its competitors. Exploding battery stories will always sell better than ones covering the flow of electrons along a conductor, the electrical equivalent of watching the paint dry.
I agree the US Coast Guard data is probably the best we have, because generally (I think there are variations between states) both boat registration and incident reporting are compulsory. As an aside, it always amuses me when it turns out the land of the free endows its citizens with the unalienable rights to life liberty and the pursuit of regulation - they are often much more regulated than we are - but it does make the data more robust in that both the numerator (number of incidents) and denominator (vessels at risk) are better known, and very importantly, rates can be determined, which in turn allows comparisons to be made, over time and place and setting. Voluntary reporting on the other hand is always subject to bias eg hot topic bias (reports more likely when something is in the news, as happened during the early stages of the covid pandemic, when every cough sniffle and sneeze was put down as covid without a shred of evidence), and, to make matters worse, you often do not know the denominator (number of vessels at risk), which means you cannot calculate rates. To understand the importance of this, consider two countries of simlar population size, one of which has more deaths than the other. But all is not as it seems. The country with more deaths has a very old population, and even though its death rate in every age band is less than the death rate in every age band in the country with fewer deaths, the fact it has a very old population compared to the country with fewer deaths means that overall it has more deaths, despite having lower mortality rates for all ages. Put another way, crude numbers (counts) can be very misleading. The country with more deaths is actually the healthier country. Without reliable valid data, we simply do not know whether LiFePO batteries are more or less dangerous than lead acid batteries.
You are also right about MAIB reports. Never a dull read (there but for the grace of God go I), they are nonetheless the maritime equivalent of medical case reports, that is, anecdotes. That does not mean they don't contain valuable lessons, they usually do, but it does limit their ability to tell us anything meaningful about actual risk in the real world eg the Cheeki Rafiki report tells me nothing about what my encapsulated ballast keel/hull with effectively non-existent AVS may or may not do.
aqua_sax
Well-Known Member
It is more likely to convince me I don't want anything to do with Victron!
fredrussell
Well-Known Member
Indeed. We’ve got no chance really. By the time I get round to ‘losing the lead’ the requirement will probably be a raft towed behind boat with the LiFePo house bank on it.
Tranona
Well-Known Member
Population data per se is of limited use for boats as just counting registrations gives no information about patterns and levels of usage. Equally inter nation comparisons are of little value because of the different boat types and patterns of usage. For example if you look at the US data the high level of things like fire and collisions occur on inland waterways and mostly small powerboats. This population is totally unlike the UK. if you look at the coastal incidents they are more like N Europe and UK - that is very low in relation to the boat population, particularly sailing boats. Australia , which is often cited in the drink boating debate is again nothing like the UK. They really do (or did) have a serious drink problem now largely reduced by heavy regulation and enforcement just like the UK road user regime.
Any comparison in terms of loss of life in boating shows the UK to be arguably among the safest countries in the world for leisure boating
Sorry for thread drift, although underlying issue of empirical data is relevant to fire risk from lithium batteries.
thinwater
Well-Known Member
Agreed.
However, your response required considerable knowledge. That is the point.
Re. dark ship, not hypothetical. You would be able to troubleshoot it, but the average cruiser, maybe not. And has he become so electronics-dependent that he can't navigate without electricity? Can he anchor? You and me sure. We started sailing in boats without electricity at all!
Re. frying electronics, that is not hypothetical. When the BMS disconnects with the alternator running full clip (agreed, a DC-DC charger is smarter) there is a brief voltage surge up to 50V and this has happened more than once.
No one mentioned sub-freezing temperatures. Not a problem most places, since it isn't old enough, long enough. But something I have to deal with in January. Not difficult, and more batteries are coming with internal protections.
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I like lithium for a number of reasons and switched over this spring. And I 100% agree that Victron has made it too complicated. But neither is it as simple and robust as LA. But I believe we are headed in the right direction and it will get simpler.
lustyd
Well-Known Member
Take a look through this forum. Lead acid is far from robust.
geem
Well-Known Member
Victron makes someone the best 12/24v solar kits on the market. You would seriously be missing out on excellent mppts and smart shunts.
AngusMcDoon
Well-Known Member
I have it on authority from a former marine electronics development engineer with whom I sail quite often (even when I'm sailing single handed) that marine electronic devices from mainstream manufacturers have load dump voltage regulators or separate protection circuits to prevent damage from disconnection events like this. A typical protection range will be -40V to +90V.
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Dockhead
Well-Known Member
I can do anything without electrical power, but would I WANT to? No!!! Without electrical power you don't even have nav lights!
I have what seems like half a ton of paper charts stuffed under every mattress on board (that's 7 of them!) but they are not kept updated and they are not complete. I found it impractical to keep paper charts, even if I gave up on updating them, to cover the waters of the more than dozen countries I cruise in. I have sextant, hand bearing compass, etc. etc. on board, but without up to date charts? So it would be a most unwelcome challenge to navigate without electronic charts.
I can get anchored with the kedge or by gravity dropping the best bower, but getting it up?!? My ground tackle weighs 400kg, nearly half an English ton.
Average cruiser or old salt, I think electrical power is mission critical for 99% of us.
Sea Change
Well-Known Member
In four years of liveaboard cruising, we've had two BMS disconnects- both due to over-current. Both happened at anchor whilst cooking. One was on my birthday when SWMBO had steak, sauce, chips, onion rings, etc etc all going at the same time. Sadly, that event killed our first (Epever) inverter. We swiftly replaced it with a Victron.
When underway, we tend to draw comparatively tiny currents from the lithium. Even with the fridges, autopilot, nav lights, etc all running, we're probably still under 20A. Cooking is going to be something pretty simple done on one ring. No steak dinners underway!
So in my experience it's not a big problem. But it's still worth planning for. The BMS could in theory cut off for some other reason. My solution was to wire up two separate power supplies for the critical equipment- one from the lithium and I've from the LA. Changeover is via keyed isolators, with only one key between them, so you have to turn off one supply to remove the key and use it to turn on the second supply.
In practise I had more power drop outs from the LA, which I eventually traced to a faulty isolator.
When underway, we tend to draw comparatively tiny currents from the lithium. Even with the fridges, autopilot, nav lights, etc all running, we're probably still under 20A. Cooking is going to be something pretty simple done on one ring. No steak dinners underway!
So in my experience it's not a big problem. But it's still worth planning for. The BMS could in theory cut off for some other reason. My solution was to wire up two separate power supplies for the critical equipment- one from the lithium and I've from the LA. Changeover is via keyed isolators, with only one key between them, so you have to turn off one supply to remove the key and use it to turn on the second supply.
In practise I had more power drop outs from the LA, which I eventually traced to a faulty isolator.
Sea Change
Well-Known Member
It may well do, but the most you'll ever actually have to lift is the weight of the anchor plus a length of chain equal to the depth of the water.
thinwater
Well-Known Member
In fact, ground tackle from seabed to boat (obviously a range) weighs more like 70-110 pounds at most. But that's still a tote!
That said, windlasses do fail for a variety of reasons, so there should always be a means of lifting the hook. I had to lift mine with a line to a primary winch once. Not too bad, really. I laid out some towels to avoid scratching. I was singlehanded, so I wanted to get it up in one long pull while staying nearish the helm.
billskip
Well-Known Member
And some anchors weigh 3 times that without the chain
aqua_sax
Well-Known Member
Is this thread beginning to drag its anchor?
Dockhead
Well-Known Member
At one time, you are correct. But over the course of the whole anchor-lifting operation, all 400kg will have to be raised, if all of the chain was out. The problem is not only peak load (so kgf, or kW), but also total work (kWH). Without electrical power (and the electric winches would be down as well as the windlass), that's quite a job.
S04
Well-Known Member
It has morphed into a combined anchor/lithium battery thread. Now that's an explosive combination.
billskip
Well-Known Member
Someone is pulling your chain
Dockhead
Well-Known Member
I've been anchored in 45 meters of water. 45 meters of 12mm chain plus a 55kg anchor is more than 200kg, or 440 pounds.
My Plan B to lift the anchor in case of windlass failure, which I've practiced and tested, is to tie on a rope and lead back to a big electric primary winch. Haul in 7 or 8 meters at a time, retie the rope, haul, rinse and repeat. It works -- but that's with power on. Without power on, it would be hand humping. Can be done of course, but could be VERY tricky, especially with strong wind blowing and/or any kind of sea state.
It is VERY DESIRABLE, to not have an interruption of electrical power.
