Lithium battery webinar by insurance company

[PeterF]

Might be an interesting webinar especially as it is coming from an insurance company.

 

 

Description

Are you wondering whether you should be making the switch to Lithium batteries onboard your boat? The technology behind Lithium batteries has come on leaps and bounds in recent years, and more and more people are seeing the benefits and making the switch to a hybrid solution or even a fully Lithium solution. But how do you do it safely, and what other factors do you need consider? With many differing opinions around, it can be hard to make an informed decision. And with the status quo being perfectly acceptable, why would anyone make the switch and potentially end up with a costly invoice to pay, a set of dead batteries on a freezing day, or even worse, a catastrophic fire? But don’t worry, we have brought together a panel of experts to help separate fact from fiction and provide trustworthy information in plain English.

 

Link to Zoom webinar details and registration

Edited November 10, 2023 by PeterF

[MtB]

31 minutes ago, PeterF said:

And with the status quo being perfectly acceptable, why would anyone make the switch and potentially end up with a costly invoice to pay, a set of dead batteries on a freezing day, or even worse, a catastrophic fire? But don’t worry, we have brought together a panel of experts to help separate fact from fiction and provide trustworthy information in plain English.

 

 

One wonders how many catastrophic LFP fires they have had claims for, so far...

 

 

[IanD]

7 minutes ago, MtB said:

 

One wonders how many catastrophic LFP fires they have had claims for, so far...

 

 

My guess is -- none... 😉

 

They do say "potentially" and they are talking about lithium batteries in general not just LFP -- I would hope the experts at the seminar will point out that chemistries like NMC (as used in many other applications including most EVs) *can* cause catastrophic fires but LFPs don't, so these are safe for boating use.

 

If they don't, they're not experts... 😉

Edited November 10, 2023 by IanD

[PeterF]

9 minutes ago, MtB said:

 

 

One wonders how many catastrophic LFP fires they have had claims for, so far...

 

 

I have registered so I will see what is said and ask that question if possible. It will also be worth seeing what they have to say on lithium iron phosphate / lead acid hybrid. I keep thinking about the Nordkyn Design view

 

The simplest safe lithium installation: leaving a sealed lead-acid battery in parallel with the lithium bank at all times allows disconnecting the lithium capacity in case of problem without any issues. The additional SLA doesn’t contribute to any meaningful capacity; its function is ensuring charging sources always see a battery in circuit.

 

They do however note that changes are needed to the charging regime and adequate protection of the LFP is still required.

[magnetman]

12 minutes ago, IanD said:

NMC (as used in many other applications including most EVs) *can* cause catastrophic fires but LFPs don't, so these are safe for boating use.

 

 

Interesting to know what the findings are in this story Investigators still uncertain about cause of 30 kWh battery explosion in Germany – pv magazine International (pv-magazine.com)

 

(house had LFP batteries)

 

 

[IanD]

15 minutes ago, PeterF said:

I have registered so I will see what is said and ask that question if possible. It will also be worth seeing what they have to say on lithium iron phosphate / lead acid hybrid. I keep thinking about the Nordkyn Design view

 

The simplest safe lithium installation: leaving a sealed lead-acid battery in parallel with the lithium bank at all times allows disconnecting the lithium capacity in case of problem without any issues. The additional SLA doesn’t contribute to any meaningful capacity; its function is ensuring charging sources always see a battery in circuit.

 

They do however note that changes are needed to the charging regime and adequate protection of the LFP is still required.

 

The Nordkyn view is correct, a small sealed LA in parallel with a big LFP bank won't do anything as far as providing power is concerned but protects against LFP disconnection.

 

It does mean the LFP BMS will control the voltages and charging/discharging, and if this doesn't suit the LA and it gets sulphated or has a short lifetime -- well, tough luck for it, if that happens replace it, it's dirt cheap.

 

The problem comes when people start with a fairly big existing LA bank and decide to put a fairly big -- usually drop-in -- LFP bank in parallel to get more capacity, in the hope this will also mean the LA still get used. Depending on which one wins as far as controlling the voltage and charging sources (probably the LFP), the likely result is that the LA does very little to add capacity (because the LFP has a much flatter voltage vs. SoC curve), and either the LA or the LFP or possibly both have a short lifetime.

 

Of course this won't show up for some time, so all the vloggers posting "Hey, my parallel LA/LFP setup is *BRILLIANT*, you should get one!!!!" probably have a nasty surprise ahead of them... 😞

 

It's possible that with careful design (e.g. use of resistive cables to try and equalise the VC slopes) a system like this can be made to work -- at least for some time -- but it's more likely that the whole thing is a bit of a dog's dinner for most naive users.

Edited November 10, 2023 by IanD

[IanD]

4 hours ago, magnetman said:

Interesting to know what the findings are in this story Investigators still uncertain about cause of 30 kWh battery explosion in Germany – pv magazine International (pv-magazine.com)

 

(house had LFP batteries)

 

 

I'll just post this again:

 

https://marinehowto.com/li-ion-be-careful-what-you-read-believe/

 

"As of yet, in more than 12 years asking for proof with images of a lithium iron phosphate battery fire that was caused by overcharging or malfunction in the BMS and offering to pay for these images we still have no images of a LiFePO4 fire..We even have images of a 12V LiFePO4 battery over-charged at 100+/-V and still there was no fire."

[magnetman]

10 minutes ago, IanD said:

I'll just post this again:

 

https://marinehowto.com/li-ion-be-careful-what-you-read-believe/

 

"As of yet, in more than 12 years asking for proof with images of a lithium iron phosphate battery fire that was caused by overcharging or malfunction in the BMS and offering to pay for these images we still have no images of a LiFePO4 fire..We even have images of a 12V LiFePO4 battery over-charged at 100+/-V and still there was no fire."

 

I believe you. You believe you. 

 

I'm still interested in the story. 

 

I've got a feeling these LFP batteries may in fact have been NMC batteries. If you buy 24v or 48v batteries from random suppliers I don't think its implausible they could be using the wrong thing. 

 

One is reminded of the rather silly 'Kilowatt labs' 'super caps' products. Claiming to have harnessed the power of capacitors when in fact all it was was a lot of little LTO batteries which look like capacitors. 

 

There will be lots of this kind of thing going on and without taking the modules apart the layman may be none the wiser. 

 

So its not so much a story of the label but what is actually inside the battery module. 

 

 

Edited November 10, 2023 by magnetman
typo and removed rude joke

[PeterF]

The webinar was not the insurance industry view on the insurability of boats with lithium batteries but a presentation on the general subject of lithium batteries, it just happened to be hosted by an insurance broker (not an underwriter). The subject matter was presented by 3 technical people, a fire investigator, a marine surveyor and the owner of a marine equipment company selling and installing amongst other things lithium battery systems. The fire inspector and the marine surveyor had some experience with inland waterways and canal boats. The marine equipment man was solely offshore and large systems based and had no understanding of inland boats / canal boats. He worked with lithium battery systems that make Victron equipment look cheap! and he was one step away from detailed systems engineering so he made a number of technical errors during the presentation.

 

Battery Chemistry

The overall view provided was, as we know that LFP are very safe compared to all the other main stream chemistries such as LCO, NMC etc. although LTO was not really mentioned much. It was accepted that these were very hard to damage and generally if damaged did not overheat and combust and thermal runaway was very unlikely. The fire investigator confirmed that nearly all battery fires were chemistries other than LFP and ones where LFP were involved may well have been due to other issues such as poor installation / failed shorting equipment but you could not always determine the root cause. The marine equipment man only works with LFP. This of course was all said with the insurance broker present so hopefully the message will diffuse throughout the industry.

 

Toys

Both the surveyor (who also does loss adjustor work for insurers) and the fire investigator said that mostly battery related fires on boats were not from the boat batteries but the "toys", e-scooters, e-bikes, e-surf boards, diving power pods (not sure this applies to canals though). Some of these and their charging units are not designed as a full system and some of the 12V adapters can get very hot. With these, the view was that if you are charging something like this, do not do it in your escape route, there was a recent case with a flat where the bike / scooter was charged in the hall and the occupants could not escape. There was another on a narrow boat with the charging happening in the engine room at one end of the boat but luckily the occupants could escape from the other end of the boat. People mentioned that e-scooters especially were prone as the battery pack is low down below the board and easily damaged if not in a rugged case. Charging bags were mentioned, a flame roof fibre glass bag which could contain to some extent a lithium battery burning. However, encasing a battery in an insulating bag during charging will mean the battery warms up more.

 

Hybrid (mixed) LA and LFP banks

At a high level the marine equipment man was quite comfortable with mixed banks and he believes that the idea is sound. He called them Lithium Extension batteries and mentioned a German company, I believe this is Bos AG who sell a very expensive lithium battery system to add to your lead acid bank. These are designed for the top daily consumption going into your lead acid for deeper discharges. This is similar to the hybrid method advocated within the canal boating world. However, when questioned about "hybrid" systems he had trouble probably because we were talking about different things. It was interesting that it was not discounted out of hand.

 

System installation

Fusing was discussed where it was noted that LFP can have a very high short circuit discharge current, especially in large offshore or propulsion systems, much higher than LA. They suggested Class T fuses capable of 20,000A @ 12V fault current (expensive) on large battery towers and ANL fuses capable of  6,000A @ 12V fault current for battery strings. They did not mention MRBF fuses which can be mounted on battery terminals with a 10,000 @ 12V fault current. This is probably one area where canal boats probably fall short by using mega fuses or strip fuses, most likely by retaining these from the lead acid install. If you can not fit fuses very close to batteries mention was made of short proof insulation sleeves for the cables. Other aspects were system communication systems (CAN), emergency shutdown buttons, fire protection plus isolation on both positive and negative leads.

 

A lot was made of professional vs self install with some discussion of the generally poor wiring in canal boats. The surveyor said most electrically based fire claims he made were due to poor installation with issues such as loose wiring where positive and negative high current cables chafed against each other causing shorts (and by inference inadequate fusing) causing something nearby to catch fire. The same was true for not having properly covered terminals on batteries and equipment. This situation with LFP batteries would be worse than with lead acid due to the higher fault currents.

 

Other bits

The issue of low temperatures on LFP was discussed and acknowledged, as well as high temp for people travelling to sunnier climes.

They agreed that now LFP was cheaper over the battery lifetime than AGM.

They suggested that DC-DC or alternator to battery chargers were one way of overcoming installs with legacy alternators to avoid expensive alternator modifications.

 

Conclusion

This was very positive, it showed that lithium batteries are viewed as being very safe and entirely practical for boat domestic systems and low power propulsion systems and was not a witch hunt. It was fairly relaxed about some of the more novel ways of adding lithium to your system as long as they were properly managed and had safety systems. The biggest area of concern was around DIY installs which have the risk of being less safe.

 

The video of the webinar will be uploaded to Youtbe at some point at https://www.youtube.com/@HavenKJ/videos

[IanD]

Sounds like they got most things right as far as LFP on narrowboats is concerned, which is encouraging for those who have already gone down this route or are thinking about doing so. It should hopefully lead to some insurance companies who currently seem to be having lithium panic attacks to adopt more sensible policies which reflect the real risks.

 

Which actually seem pretty small (and they realised this) -- yes LFP batteries do have high short-circuit currents but then LA batteries are also perfectly capable of setting wiring (and boats...) on fire with bad installation leading to short-circuits if not properly fused/protected. The problem with DIY LFP installs is not much different to DIY installs of LA batteries (and wiring in general), which surely are covered by BSS anyway?

[Sailbadthesinner]

One thing that the "expert " Paul Bailey did not get right. He said that the best way to maintain and store LiFePO4 batteries was to keep them fully charged. He repeated this several times. It is well known that this will shorten their life. 

 

[IanD]

8 minutes ago, Sailbadthesinner said:

One thing that the "expert " Paul Bailey did not get right. He said that the best way to maintain and store LiFePO4 batteries was to keep them fully charged. He repeated this several times. It is well known that this will shorten their life. 

 

 

Certainly lots of people *believe* this is the case, though when I've tried to follow back the information to the source it often refers to non-LFP lithium batteries.

 

However some battery manufacturers also say it doesn't matter what SoC they sit at as far as lifetime is concerned, what is much more important is to never over/undercharge individual cells and keep them balanced.

 

It should also be pointed out that for all users except a tiny few extremely heavy ones (full charge/discharge cycle daily, all year round) properly-managed LFP lifetime on a boat is likely to be tens of years -- so if keeping them fully charged reduces it from (for example) 40 years to 30 years, who cares? 😉

Edited November 24, 2023 by IanD

[rusty69]

10 minutes ago, IanD said:

 

Certainly lots of people *believe* this is the case, though when I've tried to follow back the information to the source it often refers to non-LFP lithium batteries.

 

However some battery manufacturers also say it doesn't matter what SoC they sit at as far as lifetime is concerned, what is much more important is to never over/undercharge individual cells and keep them balanced.

 

It should also be pointed out that for all users except a tiny few extremely heavy ones (full charge/discharge cycle daily, all year round) properly-managed LFP lifetime on a boat is likely to be tens of years -- so if keeping them fully charged reduces it from (for example) 40 years to 30 years, who cares? 😉

Certainly not me. If I get 10 years out of mine I'll be very happy. 8 years to go. 

 

Not sure what the weight of the user has to do with things though. 

[IanD]

5 minutes ago, rusty69 said:

Certainly not me. If I get 10 years out of mine I'll be very happy. 8 years to go. 

 

Not sure what the weight of the user has to do with things though. 

 

Perhaps they spend more time cooking on a gas-free boat? 😉

[peterboat]

4 hours ago, PeterF said:

The webinar was not the insurance industry view on the insurability of boats with lithium batteries but a presentation on the general subject of lithium batteries, it just happened to be hosted by an insurance broker (not an underwriter). The subject matter was presented by 3 technical people, a fire investigator, a marine surveyor and the owner of a marine equipment company selling and installing amongst other things lithium battery systems. The fire inspector and the marine surveyor had some experience with inland waterways and canal boats. The marine equipment man was solely offshore and large systems based and had no understanding of inland boats / canal boats. He worked with lithium battery systems that make Victron equipment look cheap! and he was one step away from detailed systems engineering so he made a number of technical errors during the presentation.

 

Battery Chemistry

The overall view provided was, as we know that LFP are very safe compared to all the other main stream chemistries such as LCO, NMC etc. although LTO was not really mentioned much. It was accepted that these were very hard to damage and generally if damaged did not overheat and combust and thermal runaway was very unlikely. The fire investigator confirmed that nearly all battery fires were chemistries other than LFP and ones where LFP were involved may well have been due to other issues such as poor installation / failed shorting equipment but you could not always determine the root cause. The marine equipment man only works with LFP. This of course was all said with the insurance broker present so hopefully the message will diffuse throughout the industry.

 

Toys

Both the surveyor (who also does loss adjustor work for insurers) and the fire investigator said that mostly battery related fires on boats were not from the boat batteries but the "toys", e-scooters, e-bikes, e-surf boards, diving power pods (not sure this applies to canals though). Some of these and their charging units are not designed as a full system and some of the 12V adapters can get very hot. With these, the view was that if you are charging something like this, do not do it in your escape route, there was a recent case with a flat where the bike / scooter was charged in the hall and the occupants could not escape. There was another on a narrow boat with the charging happening in the engine room at one end of the boat but luckily the occupants could escape from the other end of the boat. People mentioned that e-scooters especially were prone as the battery pack is low down below the board and easily damaged if not in a rugged case. Charging bags were mentioned, a flame roof fibre glass bag which could contain to some extent a lithium battery burning. However, encasing a battery in an insulating bag during charging will mean the battery warms up more.

 

Hybrid (mixed) LA and LFP banks

At a high level the marine equipment man was quite comfortable with mixed banks and he believes that the idea is sound. He called them Lithium Extension batteries and mentioned a German company, I believe this is Bos AG who sell a very expensive lithium battery system to add to your lead acid bank. These are designed for the top daily consumption going into your lead acid for deeper discharges. This is similar to the hybrid method advocated within the canal boating world. However, when questioned about "hybrid" systems he had trouble probably because we were talking about different things. It was interesting that it was not discounted out of hand.

 

System installation

Fusing was discussed where it was noted that LFP can have a very high short circuit discharge current, especially in large offshore or propulsion systems, much higher than LA. They suggested Class T fuses capable of 20,000A @ 12V fault current (expensive) on large battery towers and ANL fuses capable of  6,000A @ 12V fault current for battery strings. They did not mention MRBF fuses which can be mounted on battery terminals with a 10,000 @ 12V fault current. This is probably one area where canal boats probably fall short by using mega fuses or strip fuses, most likely by retaining these from the lead acid install. If you can not fit fuses very close to batteries mention was made of short proof insulation sleeves for the cables. Other aspects were system communication systems (CAN), emergency shutdown buttons, fire protection plus isolation on both positive and negative leads.

 

A lot was made of professional vs self install with some discussion of the generally poor wiring in canal boats. The surveyor said most electrically based fire claims he made were due to poor installation with issues such as loose wiring where positive and negative high current cables chafed against each other causing shorts (and by inference inadequate fusing) causing something nearby to catch fire. The same was true for not having properly covered terminals on batteries and equipment. This situation with LFP batteries would be worse than with lead acid due to the higher fault currents.

 

Other bits

The issue of low temperatures on LFP was discussed and acknowledged, as well as high temp for people travelling to sunnier climes.

They agreed that now LFP was cheaper over the battery lifetime than AGM.

They suggested that DC-DC or alternator to battery chargers were one way of overcoming installs with legacy alternators to avoid expensive alternator modifications.

 

Conclusion

This was very positive, it showed that lithium batteries are viewed as being very safe and entirely practical for boat domestic systems and low power propulsion systems and was not a witch hunt. It was fairly relaxed about some of the more novel ways of adding lithium to your system as long as they were properly managed and had safety systems. The biggest area of concern was around DIY installs which have the risk of being less safe.

 

The video of the webinar will be uploaded to Youtbe at some point at https://www.youtube.com/@HavenKJ/videos

I have the fuse at the batteries, manual cut off and an ignition controlled battery cutoff, my BSS examiner was impressed by what I had done. Like me he lives on a boat so we can't be to careful with our homes

[nicknorman]

5 hours ago, Sailbadthesinner said:

One thing that the "expert " Paul Bailey did not get right. He said that the best way to maintain and store LiFePO4 batteries was to keep them fully charged. He repeated this several times. It is well known that this will shorten their life. 

 

Yes. A few other things he got wrong or didn't mention:  a big advantage of Li, that was not mentioned, is that you don't need to run charging generators or engines for hours just to get the last 10% of charge in to ward off sulphation. And he didn't mention the issue of conventional alternators cooking themselves if connected to Li.

He did mention redundancy of sensing for battery temperature. I am not sure that I agree because an over or under temperature is highly unlikely on a canal boat if the setup is sound, and for that to co-incide with a sensor failure seems incredibly improbable - but I suppose that depends on whether you notice the temperature sensor isn't working. Maybe for built in BMS you might not. But then adding another one doesn't really help if you don't know the first one has failed because what happens if the second one fails? But I did give myself a smug pat on the back because I do have 2 battery temperature sensors available to the BMS - FWIW!

Overall as mentioned, I was pleasantly surprised by the good sense of most of it, and in particular emphasising that LiFePO4 isn't the problem, it is the other small Li-ion batteries built into cheap gadgets that are most likely to cause a fire.

 

Incidentally it did prompt me to get an insurance quote from them, even though our renewal isn't until March. Very cheap! But then I saw there were some bad reviews - but these dated from 2013 and now of course the company has different owners. If anyone on here has experience of claiming from them I'd be interested to hear it.

Edited November 24, 2023 by nicknorman

[IanD]

Just now, nicknorman said:

Yes. A few other things he got wrong or didn't mention:  a big advantage of Li, that was not mentioned, is that you don't need to run charging generators or engines for hours just to get the last 10% of charge in to ward off sulphation. And he didn't mention the issue of conventional alternators cooking themselves if connected to Li.

He did mention redundancy of sensing for battery temperature. I am not sure that I agree because an over or under temperature is highly unlikely on a canal boat if the setup is sound, and for that to co-incide with a sensor failure seems incredibly improbable - but I suppose that depends on whether you notice the temperature sensor isn't working. Maybe for built in BMS you might not. But then adding another one doesn't really help if you don't know the first one has failed because what happens if the second one fails? But I did give myself a smug pat on the back because I do have 2 battery temperature sensors available to the BMS - FWIW!

Overall as mentioned, I was pleasantly surprised by the good sense of most of it, and in particular emphasising that LiFePO4 isn't the problem, it is the other small Li-ion batteries built into cheap gadgets that are most likely to cause a fire.

 

Lots of advantages of LFP batteries weren't mentioned, but this was all about insurance and safety not how great LFPs are 🙂

 

I'd have said that the main purpose of a battery temperature sensor with LFP is to prevent charging when too cold, there are much better ways of detecting overcharging (cell voltages) way before the batteries get hot -- it does give another line of defence if the BMS goes wrong, but this also means any over-temperature cutoff has to be done independently of the BMS since if that's gone doolally anyway it's unlikely to take any notice of it...

 

(mine's also got a separate temperature sensor linked into the Cerbo as well as the one that the BMS uses to control charging)

 

As you say, a pretty good summary, much better than I think a lot of people were expecting (or fearing). Let's hope this knowledge percolates into all the insurance companies so they start making sensible decisions about LFP on boats, not stupid ones... 😉

[nicknorman]

31 minutes ago, IanD said:

 

Lots of advantages of LFP batteries weren't mentioned, but this was all about insurance and safety not how great LFPs are 🙂

 

I'd have said that the main purpose of a battery temperature sensor with LFP is to prevent charging when too cold, there are much better ways of detecting overcharging (cell voltages) way before the batteries get hot -- it does give another line of defence if the BMS goes wrong, but this also means any over-temperature cutoff has to be done independently of the BMS since if that's gone doolally anyway it's unlikely to take any notice of it...

 

(mine's also got a separate temperature sensor linked into the Cerbo as well as the one that the BMS uses to control charging)

 

As you say, a pretty good summary, much better than I think a lot of people were expecting (or fearing). Let's hope this knowledge percolates into all the insurance companies so they start making sensible decisions about LFP on boats, not stupid ones... 😉

Yes multiple sensors and one BMS  still gives a single point of failure. My BMS has an OLED display that comes on when the batteries are being charged so I’d probably notice if it wasn’t working. I think you are saying that for an over temp to occur you would have to have a charging fault AND a BMS failure to protect against the over-voltage, in which case BMS noticing a high temperature isn’t going to help as it’s already failed to isolate on over-voltage. I guess this is mostly true but I’m just thinking of other scenarios. Our batteries are in the engine bay and on a hot day with engine running fast can get to 35C, so only another 25C to go to overtemp territory. Perhaps this could be achieved by some fault condition not arising from over voltage, but I’m struggling to think of one. Repeated very high charge and discharge current, possibly, but that doesn’t seem a feasible scenario  on a canal boat.

[IanD]

18 minutes ago, nicknorman said:

Yes multiple sensors and one BMS  still gives a single point of failure. My BMS has an OLED display that comes on when the batteries are being charged so I’d probably notice if it wasn’t working. I think you are saying that for an over temp to occur you would have to have a charging fault AND a BMS failure to protect against the over-voltage, in which case BMS noticing a high temperature isn’t going to help as it’s already failed to isolate on over-voltage. I guess this is mostly true but I’m just thinking of other scenarios. Our batteries are in the engine bay and on a hot day with engine running fast can get to 35C, so only another 25C to go to overtemp territory. Perhaps this could be achieved by some fault condition not arising from over voltage, but I’m struggling to think of one. Repeated very high charge and discharge current, possibly, but that doesn’t seem a feasible scenario  on a canal boat.

That was pretty much my point, on the list of safety things to worry about with LFP redundant battery temperature sensing looks like it should be *way* down the list. A decent BMS *with remote warning when things go wrong* is probably #1, which is what ABYC are enforcing -- and means that drop-in LFP without any external communication/warning (e.g. via Bluetooth or CANbus) should be frowned on. The next is a good installation including fuses, wiring, isolation switches and so on -- but this isn't really much different to what BSS needs for LA batteries, except in detail (e.g. higher rated fuses).

 

Low-cost DIY LFP installations are the ones most likely to fall down on both counts, because "dumb" drop-in LFP are the cheapest solution, as is a poor-quality penny-pinching installation with low-quality -- possibly Chinese knockoff -- components like isolators (see link below). But that's no reason to ban them, any more than it is to ban DIY LA installations of which there are *thousands*.

 

There's a strong case to be made that a decent LFP setup is no more dangerous than a decent LA one, and may actually be lower risk because there's no risk of explosive gases and acid spills etc.

 

https://marinehowto.com/counterfeit-electrical-components-just-say-no/

Edited November 24, 2023 by IanD

[nicknorman]

9 minutes ago, IanD said:

That was pretty much my point, on the list of safety things to worry about with LFP redundant battery temperature sensing looks like it should be *way* down the list. A decent BMS *with remote warning when things go wrong* is probably #1, which is what ABYC are enforcing -- and means that drop-in LFP without any external communication/warning (e.g. via Bluetooth or CANbus) should be frowned on. The next is a good installation including fuses, wiring, isolation switches and so on -- but this isn't really much different to what BSS needs for LA batteries, except in detail (e.g. higher rated fuses).

 

Low-cost DIY LFP installations are the ones most likely to fall down on both counts, because "dumb" drop-in LFP are the cheapest solution, as is a poor-quality penny-pinching installation. But that's no reason to ban them, any more than it is to ban DIY LA installations of which there are *thousands*.

 

There's a strong case to be made that a decent LFP setup is no more dangerous than a decent LA one, and may actually be lower risk because there's no risk of explosive gases and acid spills etc.

 

While I was away on the boat the tow plane (which I maintain) at the gliding club had a problem. Battery was fine all day but suddenly won’t even turn over and there had been a funny crackling over the radio just before shutdown. Over the phone I got them to check some stuff and it was apparent that with the battery master off, the voltage on the battery posts was 12.7. But as soon as battery master switched on (couple of amps draw) the voltage on the posts fell to virtually zero. I diagnosed an internal near-fracture of the cell interconnects. New battery required. It’s just a “cooking” 32Ah open lead acid.

 

Next thing I hear, some helpful member has taken it home to charge. Not a good idea - if the fracture is above electrolyte level and nicely bathed in H2 and O2, and then you charge it and there is a tiny bit of arcing at the break …. Boom! So my point is lead acid batteries can be quite dangerous! (But you knew that!)

Edited November 24, 2023 by nicknorman

[nicknorman]

Ah, re. the cheap insurance quote, I now realise I had specified third party only. For "fully comp" it is not cheap.

[MtB]

3 minutes ago, nicknorman said:

Ah, re. the cheap insurance quote, I now realise I had specified third party only. For "fully comp" it is not cheap.

 

Did you declare your home brew LFP installation?!

[nicknorman]

No, it didn’t ask. Anyway, my system was designed and installed by a professional.

 

 

I just didn’t mention what the profession was.

[PeterF]

The video can be viewed at 

 

https://www.youtube.com/watch?v=D1IlcZyW1IM