lithium cable size

[rusty69]

5 minutes ago, MtB said:

 

 

Ah, so Rusty was on the right track. Pass this time, fail next eh?! 

Seems unlikely. I've never been right about anything before. 

[nicknorman]

1 hour ago, ditchcrawler said:

 

An alternator cable is not fused now with perhaps 550Ah of lead acid sitting on the end of it. They can pump a lot of current down into the alternator if you get a fault or short on the cable so why should  suitable lithium Life batteries be different ?

No but it is supposed to route through a battery isolator switch. I think you have to apply some common sense. A short cable in the engine bay between battery and alternator doesn’t present a big hazard, especially as it can be isolated during maintenance using the isolator switch. But compare that to Li batteries installed remotely in the warm living space and connected to the LA via long thick wires routed through bulkheads. Much more scope for a problem to arise and if it does, it is inside the cabin surrounded by wood, as opposed to being in an engine compartment which is mostly metal and probably outside the cabin space. Having a fuse at each end of a long cable  connecting batteries makes sense.

[cuthound]

10 minutes ago, ditchcrawler said:

As I posted before, they have only just remover the requirement for a flame arrester on a diesel tank vent, as someone who has a diesel cooker I know how hard it is to set fire to diesel, let alone any fumes coming out of a half inch vent. So its seams its just their idea of a hazard and who can afford to challenge them, I cant.

 

 

That may be because the fuel companies on their data sheets give the flashpoint if diesel as a minimum of 52°C.

 

When I was working one of my duties was to.stsy abreast of legislation that may affect the power and cooling part of BT.

 

BT transported diesel in trailer mounted IBC's but diesel came within the scope of the Carriage of Dangerous Goods by Road regulations 2001 because of the low flashpoint, hence my interest.

 

I had numerous samples laboratory tested and all came back with flashpoints around 80°C.

 

I tried liaising with the Department for Transport but they would not be moved, so I contacted the major diesel refiners. They told me that the lower flashpoint was theoretically possible for a relatively small amount of diesel when a refinery switched from petrol to diesel production.

 

So we had to accept that diesel was potentially much more flammable than independent tests showed. Perhaps the BSS bods did a similar exercise.

 

However in 2015 the CDGR regs changed to flashpoint for diesel to 60°C IIRC.

 

 

[ditchcrawler]

10 minutes ago, nicknorman said:

No but it is supposed to route through a battery isolator switch. 

And that is another can of worms, many on here will tell you to go direct to the batteries

[MtB]

19 minutes ago, rusty69 said:

Seems unlikely. I've never been right about anything before. 

 

On the other hand Nick is always right.

 

And nick said you were right. Was he wrong? 

 

 

[nicknorman]

41 minutes ago, ditchcrawler said:

And that is another can of worms, many on here will tell you to go direct to the batteries

There are pros and cons but the BSS is unequivocal. On the other hand, moving a wire from one side of an isolator switch to the other, doesn’t take long…

43 minutes ago, MtB said:

 

On the other hand Nick is always right.

 

Don’t exaggerate. I have been wrong before. I think it was in 1971.

[MtB]

6 minutes ago, nicknorman said:

Don’t exaggerate. I have been wrong before. I think it was in 1971.

 

 

But later it turned out you were right after all, and had made a mistake in thinking you were wrong.

 

Ummm..... 

[PeterF]

The BSS committee can just say that they are bringing the BSS into line with international standards, i.e. ISO Technical Specification ISO/TS/23625, Small craft - Lithium-ion batteries. This states 

 

4.9 In normal operation, different battery chemistries should not be connected in parallel or in series. Combining/automated charging relays should not be used between systems using different chemistries.

 

 

Edited March 29, 2023 by PeterF

[rusty69]

4 minutes ago, PeterF said:

The BSS can just say that they are bringing the BSS into line with international standards, i.e. ISO Technical Specification ISO/TS/23625, Small craft - Lithium-ion batteries. This states 

 

4.9 In normal operation, different battery chemistries should not be connected in parallel or in series. Combining/automated charging relays should not be used between systems using different chemistries.

 

 

Well, at least I will only have one lead acid battery to hide at the next examination then. 

[MtB]

2 minutes ago, rusty69 said:

Well, at least I will only have one lead acid battery to hide at the next examination then. 

 

 

Ah well, it'll be just like the old days then when I had to temporarily disconnect the gas lights once every four years.

 

Happy days....

 

[Alan de Enfield]

19 minutes ago, PeterF said:

The BSS committee can just say that they are bringing the BSS into line with international standards, i.e. ISO Technical Specification ISO/TS/23625, Small craft - Lithium-ion batteries. This states 

 

4.9 In normal operation, different battery chemistries should not be connected in parallel or in series. Combining/automated charging relays should not be used between systems using different chemistries.

 

 

 

Yes - it would be a bit if a b**ger if a boat was built complying with the RCD / RCR but failed the BSS.

 

Who has precedence ?

Internationaly agreed standards or a commercial testing house owned by a Navigation authority

 

Then of course there is the  "ISO 16315:2016 Small craft — Electric propulsion system" which detail how the system must be installed

Edited March 29, 2023 by Alan de Enfield

[nicknorman]

22 minutes ago, Alan de Enfield said:

 

Yes - it would be a bit if a b**ger if a boat was built complying with the RCD / RCR but failed the BSS.

 

Who has precedence ?

Internationaly agreed standards or a commercial testing house owned by a Navigation authority

Well if you want to put your boat on the navigation authority’s train set waterway, the latter.

[Tony1]

1 hour ago, nicknorman said:

 compare that to Li batteries installed remotely in the warm living space and connected to the LA via long thick wires routed through bulkheads.

 

 ...inside the cabin surrounded by wood, as opposed to being in an engine compartment which is mostly metal and probably outside the cabin space. Having a fuse at each end of a long cable  connecting batteries makes sense.

 

 

Alas, I pity the madman who would do such a thing.

But (just for arguments sake, obviously) let's imagine that I knew just such a madman, who was keeping his precious lithiums indoors on the end of a pair of 2 metre cables (of 35mm square)- and with no fuses on said cables.

Let's imagine that this rash- and yet somehow dashingly handsome- chap had two of these long thick cables leading into a cupboard (one from each lead acid battery), and that each cable was connected to.... oooh, I don't know- maybe a B2B charger. Yes- let's imagine the impetuous chisel-jawed specimen has used two B2B chargers. 

Whether or not our handsome protagonist has formed a personal relationship with his lithium batteries is entirely unrelated to the main question at hand, which is this- is it possible that an unscrupulous BSS inspector could find fault with this sort of setup, and could request that fuses be fitted at both ends of these cables? 

Perhaps our entirely fictional character ought to fit such fuses as a pre-emptive measure?

Luckily I would never contemplate this sort of deadly dangerous arrangement.

But if I knew someone who had done that, they might be very interested in your opinion on this issue.  I don't, obviously. 

But if I did.  

 

 

[rusty69]

6 minutes ago, Tony1 said:

But if I knew someone who had done that, they might be very interested in your opinion on this issue.  I don't, obviously. 

But if I did.  

Not asking for a friend then?

[Tony1]

6 minutes ago, rusty69 said:

Not asking for a friend then?

 

I could never befriend a man who was foolish enough to allow his lithiums to sleep indoors. 

Its like letting dogs sleep on your bed.

You let them climb up on that bed even once, and you are doomed to endless nights of ruined sleep, and jack russells scratching at your back at 4am because they aren't quite as warm and comfortable as they would like to be, and would you mind moving over a bit. 

Good job I'd never consider doing that either. 

 

[MtB]

17 minutes ago, Tony1 said:

 

Alas, I pity the madman who would do such a thing.

But (just for arguments sake, obviously) let's imagine that I knew just such a madman, who was keeping his precious lithiums indoors on the end of a pair of 2 metre cables (of 35mm square)- and with no fuses on said cables.

Let's imagine that this rash- and yet somehow dashingly handsome- chap had two of these long thick cables leading into a cupboard (one from each lead acid battery), and that each cable was connected to.... oooh, I don't know- maybe a B2B charger. Yes- let's imagine the impetuous chisel-jawed specimen has used two B2B chargers. 

Whether or not our handsome protagonist has formed a personal relationship with his lithium batteries is entirely unrelated to the main question at hand, which is this- is it possible that an unscrupulous BSS inspector could find fault with this sort of setup, and could request that fuses be fitted at both ends of these cables? 

Perhaps our entirely fictional character ought to fit such fuses as a pre-emptive measure?

Luckily I would never contemplate this sort of deadly dangerous arrangement.

But if I knew someone who had done that, they might be very interested in your opinion on this issue.  I don't, obviously. 

But if I did.  

 

 

Blimey I thought for a minute you meant ME!

 

 

 

 

[Tony1]

1 minute ago, MtB said:

 

Blimey I thought for a minute you meant ME!

 

 

My dear MTB, I will confess I was not referring to your very handsome self.

But if the handsome cap fits, I can only suggest that it be worn proudly. 

 

 

[MtB]

4 minutes ago, Tony1 said:

 

My dear MTB, I will confess I was not referring to your very handsome self.

But if the handsome cap fits, I can only suggest that it be worn proudly. 

 

It fits PERFECT. 

 

But only on backwards....

 

 

 

[Tony1]

8 minutes ago, MtB said:

 

It fits PERFECT. 

 

But only on backwards....

 

 

Oscar Wilde almost certainly once said that a gentleman who wore his cap backwards should either be 14 years old, or imprisoned for life on grounds of appalling taste.

And such a specimen should never be put in charge of a narrowboat. 

 

 

Edited March 29, 2023 by Tony1

[MtB]

8 minutes ago, Tony1 said:

 

Oscar Wilde almost certainly once said that a gentleman who wore his cap backwards should either be 14 years old, or imprisoned for life on grounds of appalling taste.

And such a specimen should never be put in charge of a narrowboat. 

 

 

If ever you think I look like I'm in charge of my narrowboat, you've probably been drinking. 

 

And I agree with that nice Mr Wilde. Here's ya cap back! 

 

 

[nicknorman]

1 hour ago, Tony1 said:

 

Alas, I pity the madman who would do such a thing.

But (just for arguments sake, obviously) let's imagine that I knew just such a madman, who was keeping his precious lithiums indoors on the end of a pair of 2 metre cables (of 35mm square)- and with no fuses on said cables.

Let's imagine that this rash- and yet somehow dashingly handsome- chap had two of these long thick cables leading into a cupboard (one from each lead acid battery), and that each cable was connected to.... oooh, I don't know- maybe a B2B charger. Yes- let's imagine the impetuous chisel-jawed specimen has used two B2B chargers. 

Whether or not our handsome protagonist has formed a personal relationship with his lithium batteries is entirely unrelated to the main question at hand, which is this- is it possible that an unscrupulous BSS inspector could find fault with this sort of setup, and could request that fuses be fitted at both ends of these cables? 

Perhaps our entirely fictional character ought to fit such fuses as a pre-emptive measure?

Luckily I would never contemplate this sort of deadly dangerous arrangement.

But if I knew someone who had done that, they might be very interested in your opinion on this issue.  I don't, obviously. 

But if I did.  

 

Stuff that is connected to a potential source of very high current (a battery) should be fused such that a short circuit can’t spray molten copper and liquid plastic insulation from the cables around, not to mention superheated copper vapour and plastic vapour. None of which makes a great face pack.

So from a lead acid battery to a remote B2B, you need a fuse near the LA. You don’t need a fuse near the B2B. From the B2B to the Li it would be advisable to have a fuse near the Li, especially if the installation instructions say so, but presuming the B2B is located close to the Li and thus the cable is short and thus unlikely to suffer damage, then probably the need is less.

[IanD]

2 hours ago, PeterF said:

The BSS committee can just say that they are bringing the BSS into line with international standards, i.e. ISO Technical Specification ISO/TS/23625, Small craft - Lithium-ion batteries. This states 

 

4.9 In normal operation, different battery chemistries should not be connected in parallel or in series. Combining/automated charging relays should not be used between systems using different chemistries.

 

 

But that rule says "should" which AFAIK means advisory, like various things already in the BSS; if it was a requirement it would say "must".

 

Unless ISO has a different way to distinguish between the two, which seems unlikely because these are legal meanings...

[Tony1]

10 hours ago, nicknorman said:

Stuff that is connected to a potential source of very high current (a battery) should be fused such that a short circuit can’t spray molten copper and liquid plastic insulation from the cables around, not to mention superheated copper vapour and plastic vapour. None of which makes a great face pack.

So from a lead acid battery to a remote B2B, you need a fuse near the LA. You don’t need a fuse near the B2B. From the B2B to the Li it would be advisable to have a fuse near the Li, especially if the installation instructions say so, but presuming the B2B is located close to the Li and thus the cable is short and thus unlikely to suffer damage, then probably the need is less.

 

 

Merci buckets young man- my foolish and fictional friend will get on it.

 

 

 

 

[ditchcrawler]

11 hours ago, nicknorman said:

Stuff that is connected to a potential source of very high current (a battery) should be fused such that a short circuit can’t spray molten copper and liquid plastic insulation from the cables around, not to mention superheated copper vapour and plastic vapour. None of which makes a great face pack.

So from a lead acid battery to a remote B2B, you need a fuse near the LA. You don’t need a fuse near the B2B. From the B2B to the Li it would be advisable to have a fuse near the Li, especially if the installation instructions say so, but presuming the B2B is located close to the Li and thus the cable is short and thus unlikely to suffer damage, then probably the need is less.

But how many boats do you think have a fuse between the battery and the alternator, I would suggest this is normally the smallest cable connected directly to the batteries which then runs off to a big lump of hot iron where the alternator is mounted. I would suggest this is possibly a greater hazard with LA batteries as a BMS could well switch off with Life batteries. Your thoughts.

[nicknorman]

3 hours ago, ditchcrawler said:

But how many boats do you think have a fuse between the battery and the alternator, I would suggest this is normally the smallest cable connected directly to the batteries which then runs off to a big lump of hot iron where the alternator is mounted. I would suggest this is possibly a greater hazard with LA batteries as a BMS could well switch off with Life batteries. Your thoughts.

As I understand it a fuse isn’t needed by the regs and isn’t really desirable in case it should decided to pop due to old age etc. however an isolator switch is.  Obviously it depends on the individual boat’s layout, but typically the alternator + cable is quite short and doesn’t route through bulkheads etc. The main hazard is probably spanner contact during maintenance, which is why the battery should route via a battery isolator that can be turned off during maintenance.

 

On our boat there are 2 x 12v alternators. The small engine alternator routes via an isolator to the starter battery. The big alternator routes to the lithium batteries, not via the isolator switch (which isolates the loads from the battery apart from the Combi). However just prior to the Li batteries there is a 500A fuse (built into the Mastershunt).

 

So I think in summary, a good installation is one that either has the alternator routing via a fuse, or via an isolator. Routing directly from battery to alternator is not advisable.

Edited March 30, 2023 by nicknorman