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Cheap LiFePO4 BMS?


jetzi

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2 minutes ago, magnetman said:

 

I probably am now but no intention of driving again so it doesn't matter.

 

 

What actually happened is that I got it wrong. The car was insured fully comp because it is cheaper but in my head it was only 3rd party. This is because I would under no circumstances claim on insurance for something which was my fault. It goes against the grain. Similar with contents insurance. Simple answer is don't own any possessions you can't afford to lose.

 

I really do have a significant dislike of the principle of insurance. Big time.

 

 

The CO20B cells are alright. High quality, Nobody is going to go up in flames unless they do something very silly.

 

I've experienced a thermal runaway with a jump pack due to overvoltage. Its not ideal but that was cheap rubbish and I did go well above the top voltage. 

 

The problem is that the "something very silly" can be not just physical damage but also a BMS which doesn't monitor/balance individual cell voltages and causes gross overcharging of a cell -- this can (and has) happened without the overall battery voltage going above the top limit, and especially if the cells are not new and a matched set to start off with, or one has lost capacity.

 

So in EVs which are built with new matched cells and have sophisticated/thoruoghly-tested BMS (and cell cooling) the risk of this happening is small.

 

For a DIY system the risk is much higher, often the quality and matching of the cells is not known, the BMS may not be well enough designed or badly constructed or wired up.

 

Big DIY NMC battery banks for boats are really *not* a good idea, even if you know what you're doing, because if they go wrong they can go *horribly* wrong -- LFP are *far* safer, unlike NMC there is no recorded case of a catastrophic boat fire caused by them.

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LFP is definitely the safer option yes. I wouldn't argue with that but I think you are a bit alarmist about the dangers of NMC batteries.

 

It is a fair point though. I must admit I thought e scooters were banned on underground because of the obvious problem of idiots riding them around in the stations and causing accidents. I didn't realise it was the fire risk. I suspect even if they had LFP batteries they still might be banned for other reasons but yes the fire thing is a good argument for steering clear.

 

In the case of the batteries being discussed I do know that extensive testing was carried out and they are actually good cells.

Edited by magnetman
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24 minutes ago, magnetman said:

LFP is definitely the safer option yes. I wouldn't argue with that but I think you are a bit alarmist about the dangers of NMC batteries.

 

It is a fair point though. I must admit I thought e scooters were banned on underground because of the obvious problem of idiots riding them around in the stations and causing accidents. I didn't realise it was the fire risk. I suspect even if they had LFP batteries they still might be banned for other reasons but yes the fire thing is a good argument for steering clear.

 

In the case of the batteries being discussed I do know that extensive testing was carried out and they are actually good cells.

 

I did say that the risk was small given the numbers out there, but also that such fires have happened in all those applications of NMC batteries, for which there is plenty of evidence. That's not being alarmist, it's why they've been banned or controlled in planes, trains, boats...

 

E-scooters are banned by TfL -- on buses, tubes and trains -- because of the fire risk, no other reason. There were several cases of e-scooter fires that caused damage and were very difficult to extinguish.

 

It doesn't matter how "good" the cells are or how much they were tested, the fact remains that if something does go wrong NMC batteries can start a very difficult-to-extinguish fire (rapid thermal runaway) and LFP can't, and there are plenty of examples in all the applications I mentioned. It doesn't mean that they're so dangerous as to be unusable, but the risk is there and as a consequence they have been effectively banned from some places.

 

For applications where energy density/weight is crucial like cars/phones/laptops NMC and similar will carry on being used, though cars are now starting to shift to LFP because of lower cost and the fact that a theoretically lower energy density is counteracted by weight saving from not needing such robust protection against fire/damage.

 

For boats where the higher energy density of NMC is not needed, it seems crazy to accept the added risk of using them when LFP don't have this -- especially when a boat fire may be very difficult to extinguish due to mooring inaccessibility. And that's even if you ignore the insurance issue, which could become a killer in the future if it becomes difficult/impossible to get cover.

 

P.S. If you (and the supplier) are confident that the cells are so "good" that the fire risk is negligible, try asking the supplier if they'll indemnify you against any resulting damage if your insurer refuses to pay out... 😉

Edited by IanD
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4 hours ago, magnetman said:

 

James the battery man did also have a very large number of EIG pouch cells (CO20B) and he had the bus bars custom laser cut for them from Aluminium and some copper bus bars too.

 

These are NMC pouch cells in rigid plastic holders and screw terminals rather than bare pouches.

 

I thought @Peterboat had the Valence batteries which are LFP in 4S blocks.

 

James used loads and loads of the EIG cells for his own boat propulsion system.

 

Reading his description I think Peter may have done the same thing. They are thin cells 20Ah each at 3.65v.

 

These ones [img]https://i.ebayimg.com/images/g/zDgAAOSwqR5eQZPo/s-l1600.jpg[/img]

 

 

They really are the business, really well matched

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10 minutes ago, peterboat said:

They really are the business, really well matched

I'm sure they are, but they're still NMC, which means they still have the risk of thermal runaway if something goes wrong -- and I don't see any per-cell temperature sensors anywhere to try and detect this... 😉

 

Do you know if James had any problem getting insurance for his boat after stuffing it with these -- and did he tell them exactly what he was doing, and how long ago was this?

 

Lithium battery fires have come under much closer scrutiny from insurers in the last few years following well-publicised problems like Boeing (battery fires on the 787), e-scooters, lumpy water electric boats, and EVs...

 

(and with boats, agreed/co-operative policy advice/restrictions between insurance associations in the US (ABYC) and the EU -- and presumably now the UK...)

Edited by IanD
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50 minutes ago, magnetman said:

 

I probably am now but no intention of driving again so it doesn't matter.

 

 

What actually happened is that I got it wrong. The car was insured fully comp because it is cheaper but in my head it was only 3rd party. This is because I would under no circumstances claim on insurance for something which was my fault. It goes against the grain. Similar with contents insurance. Simple answer is don't own any possessions you can't afford to lose.

 

I really do have a significant dislike of the principle of insurance. Big time.

 

 

The CO20B cells are alright. High quality, Nobody is going to go up in flames unless they do something very silly.

 

I've experienced a thermal runaway with a jump pack due to overvoltage. Its not ideal but that was cheap rubbish and I did go well above the top voltage. 

James did terrible things to them to see what would happen! Direct short, connected one cell to a 12 volt battery,  and burst one whilst it was charging no flames apart from the direct short which burnt the cable out!

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4 minutes ago, peterboat said:

James did terrible things to them to see what would happen! Direct short, connected one cell to a 12 volt battery,  and burst one whilst it was charging no flames apart from the direct short which burnt the cable out!

So what? Did he see what happened if one cell develops an internal short due to dendritic growth, or an insulator breakdown at the corner of the pouch cell? No of course not, because he's got no way to do this -- but it's what caused fires in several of the cases I mentioned, due to either manufacturing faults or mistreatment.

 

3 minutes ago, magnetman said:

It is shocking how many people get badly injured in accidents in the kitchen.

Also climbing ladders, driving cars, mountain climbing, chainsawing. What's your point?

Edited by IanD
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5 minutes ago, IanD said:

I'm sure they are, but they're still NMC, which means they still have the risk of thermal runaway if something goes wrong -- and I don't see any per-cell temperature sensors anywhere to try and detect this... 😉

 

Do you know if James had any problem getting insurance for his boat after stuffing it with these -- and did he tell them exactly what he was doing, and how long ago was this?

 

Lithium battery fires have come under much closer scrutiny from insurers in the last few years following well-publicised problems like Boeing (battery fires on the 787), e-scooters, lumpy water electric boats, and EVs...

 

(and with boats, agreed/co-operative policy advice/restrictions between insurance associations in the US (ABYC) and the EU -- and presumably now the UK...)

He has been using them for 3 years that I know of, you will get to know first as he is on the Thames if anything goes wrong.....................

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Dendritic growth is a real worry.

Just now, peterboat said:

He has been using them for 3 years that I know of, you will get to know first as he is on the Thames if anything goes wrong.....................

 

I think he has perfected the DIY miniaturised nuclear reactor now so no need for the batteries going forwards (or backwards).

3 minutes ago, IanD said:

Also climbing ladders, driving cars, mountain climbing, chainsawing. What's your point?

 

Risk taking can sometimes be rewarding specially when nothing bad happens.

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8 minutes ago, peterboat said:

He has been using them for 3 years that I know of, you will get to know first as he is on the Thames if anything goes wrong.....................

Again, so what?

 

Like I said these battery fires are not that common, with one boat out there (James) it might be (for example) 100 years before he'd get one, because that's how failure rates work.

 

With 100 boats it would then mean 1 fire a year, with 1000 almost one a month and so on.

 

When there was only one guy juggling chainsaws every night with Circus Archaos he got away with it for years. Well, until he almost amputated his leg. Didn't do the act after that, turns out it was quite risky after all... 😞

 

It's how risk works, but you don't seem to understand that -- the experience of you and your mates (or James for 3 years) proves absolutely nothing about the risk... 😉

 

P.S. I notice you've avoided answering the insurance question -- is that because you don't know, or that you know he's relying on "don't ask don't tell"?

Edited by IanD
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4 minutes ago, IanD said:

Again, so what?

 

Like I said these battery fires are not that common, with one boat out there (James) it might be (for example) 100 years before he'd get one, because that's how failure rates work.

 

With 100 boats it would then mean 1 fire a year, with 1000 almost one a month and so on.

 

When there was only one guy juggling chainsaws every night with Circus Archaos he got away with it for years. Well, until he almost amputated his leg. Didn't do the act after that, turns out it was quite risky after all... 😞

 

It's how risk works, but you don't seem to understand that -- the experience of you and your mates (or James for 3 years) proves absolutely nothing about the risk... 😉

 

P.S. I notice you've avoided answering the insurance question -- is that because you don't know, or that you know he's relying on "don't ask don't tell"?

 

I haven't seen anyone trying to sell NMC batteries for boats.

 

I'm not sure and have not checked but I don't think there are any products available on the market. LFP and the infinitely superior LTO are the ones which go in boats.

 

Discussing other people's choice of insurance (or choice not to insure the boat if not legally obliged to do so) is not a very cool topic.

 

 

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53 minutes ago, IanD said:

Again, so what?

 

Like I said these battery fires are not that common, with one boat out there (James) it might be (for example) 100 years before he'd get one, because that's how failure rates work.

 

With 100 boats it would then mean 1 fire a year, with 1000 almost one a month and so on.

 

When there was only one guy juggling chainsaws every night with Circus Archaos he got away with it for years. Well, until he almost amputated his leg. Didn't do the act after that, turns out it was quite risky after all... 😞

 

It's how risk works, but you don't seem to understand that -- the experience of you and your mates (or James for 3 years) proves absolutely nothing about the risk... 😉

 

P.S. I notice you've avoided answering the insurance question -- is that because you don't know, or that you know he's relying on "don't ask don't tell"?

I don't know about his insurance as its nowt to do with me Ian. I know that my insurance know I have the batteries I do and that is what matters. 

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4 hours ago, magnetman said:

 

I haven't seen anyone trying to sell NMC batteries for boats.

 

I'm not sure and have not checked but I don't think there are any products available on the market. LFP and the infinitely superior LTO are the ones which go in boats.

 

Discussing other people's choice of insurance (or choice not to insure the boat if not legally obliged to do so) is not a very cool topic.

 

 

Some people on this forum have suggested using (cheap) secondhand EV batteries on boats, and almost all these are NMC -- yes Peter I know yours aren't, but all the sites selling secondhand EV batteries are.

 

LTO have advantages such as ultrafast charging which are irrelevant to boats, and they're more expensive and with lower density than LFP.

 

Discussing insurance is relevant when people keep putting forward somebody else's NMC boat battery as if it's the bees knees, because lots of people believe what they read on the Internet without being aware of the problems.

4 hours ago, peterboat said:

I don't know about his insurance as its nowt to do with me Ian. I know that my insurance know I have the batteries I do and that is what matters. 

So if you don't know how safe (or not...) NMC batteries on boats are or whether they can be insured or not, maybe you should stop promoting them as brilliant? 😉

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29 minutes ago, IanD said:

Some people on this forum have suggested using (cheap) secondhand EV batteries on boats, and almost all these are NMC -- yes Peter I know yours aren't, but all the sites selling secondhand EV batteries are.

 

LTO have advantages such as ultrafast charging which are irrelevant to boats, and they're more expensive and with lower density than LFP.

 

Discussing insurance is relevant when people keep putting forward somebody else's NMC boat battery as if it's the bees knees, because lots of people believe what they read on the Internet without being aware of the problems.

So if you don't know how safe (or not...) NMC batteries on boats are or whether they can be insured or not, maybe you should stop promoting them as brilliant? 😉

Given James is a major seller of Lithium batteries, I suspect he knows the problems with them. As I said he did extreme testing to destruction on them to see the results, not laboratory tests but more in keeping with what we would do to them!

I watched the videos and they didn't burn, I have them on my little car and John has them on his off grid system, which is in a steel container away from his house. 

 

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50 minutes ago, IanD said:

Some people on this forum have suggested using (cheap) secondhand EV batteries on boats, and almost all these are NMC -- yes Peter I know yours aren't, but all the sites selling secondhand EV batteries are.

There's at least half a dozen of us on here, probably more that are using 2nd hand EV batteries, (and have been for nearly 5 years in my case). All of us are using LFP so wish you'd stop stating this as fact when it can provide a cheaper route for some people. Some are the Valence batteries that Peter and others are using, and some are Winston/Thundersky ones like ours.

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8 hours ago, Tom and Bex said:

There's at least half a dozen of us on here, probably more that are using 2nd hand EV batteries, (and have been for nearly 5 years in my case). All of us are using LFP so wish you'd stop stating this as fact when it can provide a cheaper route for some people. Some are the Valence batteries that Peter and others are using, and some are Winston/Thundersky ones like ours.

Go and look on the web for secondhand EV batteries. They're almost all from current EVs like BMW, Nissan, Jaguar. All these are NMC. Including the ones that James sells, so he's hardly an impartial observer... 😉

 

If you can find secondhand LFP from EVs then great, use them in a DIY system like you have -- if things go wrong the worst that will happen is you'll destroy expensive batteries or yournalternator.

 

But Peter keeps going on about how great James's NMC batteries are, when *every* recommendation from people *who actually understand the issue in depth* is that these should *not* be used on boats, because of safety and insurance problems, and *especially* not in a DIY system.

 

If James thinks he knows better and is willing to take the risk then that's his lookout, but promoting such a system to "lithium newbies" is nothing short of irresponsible.

 

So as long as Peter keeps doing this -- and it's obvious from these posts and many others that he doesn't understand that "him and his mates" experience is anecdotal, not valid data -- I'll keep on restating the risks.

Edited by IanD
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1 hour ago, IanD said:

Go and look on the web for secondhand EV batteries. They're almost all from current EVs like BMW, Nissan, Jaguar. All these are NMC. Including the ones that James sells, so he's hardly an impartial observer... 😉

 

If you can find secondhand LFP from EVs then great, use them in a DIY system like you have -- if things go wrong the worst that will happen is you'll destroy expensive batteries or yournalternator.

 

But Peter keeps going on about how great James's NMC batteries are, when *every* recommendation from people *who actually understand the issue in depth* is that these should *not* be used on boats, because of safety and insurance problems, and *especially* not in a DIY system.

 

If James thinks he knows better and is willing to take the risk then that's his lookout, but promoting such a system to "lithium newbies" is nothing short of irresponsible.

 

So as long as Peter keeps doing this -- and it's obvious from these posts and many others that he doesn't understand that "him and his mates" experience is anecdotal, not valid data -- I'll keep on restating the risks.

Have you ever thought that he has a proper control system on them? Both John and I do on ours, also he sells a lot of LifePo4s many on here have bought them from him, just keep on rambling Ian!

Edited by peterboat
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21 minutes ago, peterboat said:

Have you ever thought that he has a proper control system on them? Both John and I do on ours, also he sells a lot of LifePo4s many on here have bought them from him, just keep on rambling Ian!

Yes Peter, I have thought that 🙂

 

No matter how good a control system he has -- and I didn't see any individual cell temperature sensors, which are good practice for any NMC installation -- it doesn't change the fact that NMC batteries are universally advised against for boats, by industry-respected people who've spent *far* longer working with lithium batteries than him, and also who don't have a vested interest in making them look good because they make money by selling them online... 😉

 

If you want to carry on ignoring all this then that's up to you, but it looks to me like you're either being naive, misunderstanding risk (again), or deliberately ignoring facts that don't fit with your opinions.

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8 minutes ago, IanD said:

Yes Peter, I have thought that 🙂

 

No matter how good a control system he has -- and I didn't see any individual cell temperature sensors, which are good practice for any NMC installation -- it doesn't change the fact that NMC batteries are universally advised against for boats, by industry-respected people who've spent *far* longer working with lithium batteries than him, and also who don't have a vested interest in making them look good because they make money by selling them online... 😉

 

If you want to carry on ignoring all this then that's up to you, but it looks to me like you're either being naive, misunderstanding risk (again), or deliberately ignoring facts that don't fit with your opinions.

Know body has shown a picture of his battery setup so how do you know what he has done? What has been shown is a picture of the batteries with connectors Andrew pulled it from the internet

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It strikes me this has now got into the same situation as questions about boats with no RCR/RCD and my replies to questions about engine oils. The situation in all cases was clearly stated and the relevant warnings or POTENTIAL consequences given. Then those who did not like the warnings set out to discredit them by all sorts of arguments. Just as in the RCR/RCD thread when I asked if the person pho poohing the warnings was ready to give indemnity or pay for insurance against the risk they stayed very quiet and declined. 

 

From what I have read about lithium batteries it seems to me that Ian is simply warning about a potential risk with certain types, those risks being fairly well known, where as Peter seems to be trying to deny the potential risk. It seems that Peter may have more than straight commercial relationship with the vendor discussed in this topic so I am not sure exactly how independent his opinion is. He may be right that there is no rick, but other sources seem to contradict this.

 

In all cases I feel the precautionary principle should ideally be applied and that suggests to me that NMC batteries are probably best avoided for boat installations UNLESS adequate precautions can be built into the boat to control or limit damage from a battery fire. Possibly the batteries being contained in a flood chamber so they can be totally immersed, but thah would add to cost so paying more for a safer form of battery may be cost effective.

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37 minutes ago, peterboat said:

Know body has shown a picture of his battery setup so how do you know what he has done? What has been shown is a picture of the batteries with connectors Andrew pulled it from the internet

Wasn't that a photo of his setup earlier in the thread, with his much-vaunted "laser-cut aluminium busbars" connecting them all together -- and no temperature sensors, since these would have to be embedded in or sandwiched between the cells?

 

None of which makes any difference to the fact that promoting/recommending NMC battery use on boats is irresponsible. Probably the two best sources of information about lithium batteries on boats are Eric Bretscher at nordkyndesign.com and Rod Collins at marinehowto.com , both have many years of real experience with a wide variety of lithium batteries both on boats and in the lab, Rod has acted as the technical adviser to ABYC on this and helped define the insurance industry standards.

 

I would rate their knowledge *far* above somebody who promotes NMC batteries and sells them on eBay, for obvious reasons. Both categorically state that NMC cells (as opposed to LFP) are *strongly* advised against for use on boats, even with professional design and installation, and just plain shouldn't be used by DIY installers. Not ever. Not even if they're cheap and look cool.

 

The fact that James might be a thoroughly good chap who talks the talk (and one of your mates, who sold you some batteries?) is irrelevent.

Edited by IanD
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13 hours ago, IanD said:

 

 

LTO have advantages such as ultrafast charging which are irrelevant to boats, and they're more expensive and with lower density than LFP.

 

If course ultra fast charging is relevant with boats ! If we are to eventually have the majority of boats powered by batteries then ultra fast charging will be the key to the whole thing or it won't work properly. 

 

As for the NMC/LFP arguments, these people have a good page about it.

 

NMC is widely used in maritime installations BUT if you are doing a DIY job then it is more risky. 

 

https://echandia.se/insights/article/lfp-nmc-batteries/

 

 

I like the look of the BYD 'blade' cells (LFP) I think a really nice canal boat propulsion battery bank could be made with those. 

 

However I still think a smaller bank of LTO would be the way to do it for propulsion. 

 

Edited by magnetman
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