Wiring for Lifepo4

[PaulRainbow]

I had already forked out for a t class and holder before choosing the battery and I’m not going to waste £200 worth of gear. But fitting it in my limited space is a pain

Space can be a pain in a lot of cases, but well done for fitting an appropriate fuse

 

[geem]

I had already forked out for a t class and holder before choosing the battery and I’m not going to waste £200 worth of gear. But fitting it in my limited space is a pain

Do you know the European equivalent of class T fuses are NH fuses. Similar issue with space but very much cheaper to buy. The fuses themselves are £5-8 each

 

[Buck Turgidson]

Do you know the European equivalent of class T fuses are NH fuses. Similar issue with space but very much cheaper to buy. The fuses themselves are £5-8 each

now you tell me!!!

 

[geem]

now you tell me!!!

You never asked

 

[john_morris_uk]

Do you know the European equivalent of class T fuses are NH fuses. Similar issue with space but very much cheaper to buy. The fuses themselves are £5-8 each

I hadn’t heard of NH fuses. A quick Google contradicts your suggestion that they’re equivalent.

No, a Class T fuse and an NH fuse are not the same, although they both serve as high-current protection fuses. NH fuses are designed for general-purpose low-voltage applications and have a breaking capacity exceeding 100kA. Class T fuses, on the other hand, are specifically designed for current limiting and extremely fast response, with a minimum interrupt rating of 200,000 amps.

Key Differences:

• Purpose: NH fuses are for general-purpose protection, while Class T fuses are for high-current, fast-acting, and current-limiting applications.
  
  
• Interrupt Rating: NH fuses have a breaking capacity exceeding 100kA, while Class T fuses have a minimum interrupt rating of 200,000 amps.
  
  
• Speed: Class T fuses are designed for extremely fast response, while NH fuses have a slower response time.
  
  
• Applications: NH fuses are commonly used in substations, distribution boards, and for protecting large electrical devices like motors, while Class T fuses are used in high-power circuits, battery systems, and applications requiring fast-acting protection, such as those with variable speed drives or surge-sensitive components.

 

[shanemax]

I luv lithium. I see in the news yet another car carrier, half way across the Pacific is abandoned and ablaze, the crew wont even have a go at fighting a lithium fire. Lithium is an imperfect science and would have been banned if not for the green lobby.

 

[PaulRainbow]

I luv lithium. I see in the news yet another car carrier, half way across the Pacific is abandoned and ablaze, the crew wont even have a go at fighting a lithium fire. Lithium is an imperfect science and would have been banned if not for the green lobby.

What i love even more than Lithium is the people who cannot tell the difference between the various types of Lithium.

 

[Ceirwan]

I luv lithium. I see in the news yet another car carrier, half way across the Pacific is abandoned and ablaze, the crew wont even have a go at fighting a lithium fire. Lithium is an imperfect science and would have been banned if not for the green lobby.

When you consider the (low) failure rate of the literally billions of devices powered by a lithium battery worldwide, there's an argument to make that its actually incredibly safe. And that's before taking into account the many different chemistries, some of which are far safer than others.

Ironically you quite possibly wrote that from a phone, laptop or tablet with a ... lithium battery.

 

[PaulRainbow]

I hadn’t heard of NH fuses. A quick Google contradicts your suggestion that they’re equivalent.

That looks very much like an AI response, the quoted AIC ratings are for AC, DC is completely different John.

"Low voltage" ? NH fuses can be rated at 1500 V plus.

A 200A Blue Sea fuse has a 20,000 AIC @ 125 VDC

A 200A Mersen NH fuse has a 50,000 AIC @ 1000V

 

[geem]

I hadn’t heard of NH fuses. A quick Google contradicts your suggestion that they’re equivalent.

I hadn’t heard of NH fuses. A quick Google contradicts your suggestion that they’re equivalent.

There are sub categories of NH fuses. You just need the correct version.
NH Fuses Explained

 

[shanemax]

Yes......I use lithium, who doesn't, but I will not have any thing on board, especially bolted down batteries, that I cannot throw over the side. As I have said before try booking a couple of 100amp lithium batteries (any type of lithium) as air cargo on ANY airline. I never get an answer to this fact and it is always ignored. Perhaps the airlines are all wrong. The largest lithium battery I have on board is 5 amps.(laptop) and if this started " off gassing" then went into " thermal run-away", that would be a major problem. What would 200 amps be like.
Airlines classify lithium batteries as dangerous goods. I wonder why.

 

[PaulRainbow]

Yes......I use lithium, who doesn't, but I will not have any thing on board, especially bolted down batteries, that I cannot throw over the side. As I have said before try booking a couple of 100amp lithium batteries (any type of lithium) as air cargo on ANY airline. I never get an answer to this fact and it is always ignored. Perhaps the airlines are all wrong. The largest lithium battery I have on board is 5 amps.(laptop) and if this started " off gassing" then went into " thermal run-away", that would be a major problem. What would 200 amps be like.
Airlines classify lithium batteries as dangerous goods. I wonder why.

You keep coming out with this nonsesne, yet fail to grasp that LifePO4 instalations, properly done, are as safe as LA. Actually, more so, as LifePO4 are fully managed by the BMS. LA, virtually no management on boats fail, get hot, give off hydrogen and can explode.

Airlines won't allow all sorts of things onboard, doesn't mean they are unsafe when used properly. As it happens, you can take Lithium batteries on a plane in carry on luggage. There are restrictions on lifejackets on a plane, but do you have any onboard ?

 

[geem]

Yes......I use lithium, who doesn't, but I will not have any thing on board, especially bolted down batteries, that I cannot throw over the side. As I have said before try booking a couple of 100amp lithium batteries (any type of lithium) as air cargo on ANY airline. I never get an answer to this fact and it is always ignored. Perhaps the airlines are all wrong. The largest lithium battery I have on board is 5 amps.(laptop) and if this started " off gassing" then went into " thermal run-away", that would be a major problem. What would 200 amps be like.
Airlines classify lithium batteries as dangerous goods. I wonder why.

My lifepo4 cells were air frieghted from Miami to Antigua.
You don't make any distinction between lithium chemistry's. Do you know there are 5 popular lithium chemistry's in general use for various applications? The safest one is lifepo4. It's the reason why they are chosen by 99% of cruisers for boats.
Rod Collins who runs the website Marine How To has had a bet running for years that nobody can provide him a photo of a burning lifepo4 battery. Rod is on the technical committee of the ABYC. He was instrumental in writing the lithium standard for ABYC. Rod subjected lifepo4 batteries to every conceivable test the ABYC technical committee could think off and they could not cause a fire. Would you care to provide evidence that lifpo4 lithium cells are dangerous on sailing boats?
Your laptop battery is not lifepo4 by the way.

 

[Sea Change]

Oh look, the ignore button. There, that's better.

 

[shanemax]

You keep coming out with this nonsesne, yet fail to grasp that LifePO4 instalations, properly done, are as safe as LA. Actually, more so, as LifePO4 are fully managed by the BMS. LA, virtually no management on boats fail, get hot, give off hydrogen and can explode.

Airlines won't allow all sorts of things onboard, doesn't mean they are unsafe when used properly. As it happens, you can take Lithium batteries on a plane in carry on luggage. There are restrictions on lifejackets on a plane, but do you have any onboard ?

You never fail to amaze me with your utter crap. You can carry a life jacket with two CO2 cartridges on any airline as hand luggage Try loading a 100 amp lithium battery as hand luggage and you will be physically removed from the plane if you do not leave voluntarily. How can a half intelligent person make a comparison like you have. Is a life jacket "dangerous goods" Try Youtube and search Lithium batteries gassing off, or there again perhaps you better not, so you can continue living in your fantasy unreal world.

 

[Frayed Knot]

I can’t believe I’d ever say this but I rather miss the entertainment of Bigplumbs’ brain-farts (I wonder why he’s not around here anymore)
Anyway, it’s nice that someone is willing to take over.
Big shoes to fill though.

 

[PaulRainbow]

You never fail to amaze me with your utter crap. You can carry a life jacket with two CO2 cartridges on any airline as hand luggage

Same as carrying small Lithium batteries on as hand luggage, both are allowed.

Try loading a 100 amp lithium battery as hand luggage and you will be physically removed from the plane if you do not leave voluntarily.

Try taking a box full of Co2 cartridges onboard, same thing will happen.

How can a half intelligent person make a comparison like you have. Is a life jacket "dangerous goods" Try Youtube and search Lithium batteries gassing off, or there again perhaps you better not, so you can continue living in your fantasy unreal world.

You miss the point entirely. YOU cannot take 100Ah batteries onboard, any more then YOU can take lots of other things onboard, but, there are plane loads of LifePO4 batteries flying all around the World every day. How do you imagine that all of those Chinese cells/batteries (the majority originate from China) get all around the World, you think the fairies deliver them, or maybe that's what Santa does when he's not busy at Christmas.

 

[PaulRainbow]

I can’t believe I’d ever say this but I rather miss the entertainment of Bigplumbs’ brain-farts (I wonder why he’s not around here anymore)
Anyway, it’s nice that someone is willing to take over.
Big shoes to fill though.

Looks like he has big feet

 

[Daverw]

I’ve just done a tour of New Zealand that included 10 various flight, all with two larger lithium battery’s with me for my mobility scooter, they all had to be pre notified and carried in hand luggage but no issue, the airlines are just careful and don’t want them inaccessible in the hold

 

[Dockhead]

I'm struggling to think of under what circumstances you would want to isolate an individual battery, where the fuse wouldn't be sufficient to deal with whatever was going on? And the isolator would presumably be in very close proximity to the battery so if it was something truly catastrophe happening (dead short?) you're not going to want to be there.

Maybe it doesn't do any harm but it is adding extra components and connections, and a high quality, high amperage isolator is certainly not cheap.

It's entirely possible I've not thought this through and there are some scenarios I've not accounted for.

As for battery cable lengths... what are your thoughts on mixing different capacities of LFP battery? From the research I did it seemed that you could pair up batteries of wildly different sizes without any real problems. I'm using one 271Ah and one 280Ah pack, but I've heard of things like 100+300Ah systems which worked, apparently, just fine.

Removing the fuse is not a good way to isolate a large battery. All the more since the Type T's preferred for this are bolted in.

MOSFET type BMS's (like the JK BMS) can switch the battery off with the MOSFETs. But I believe you need a failsafe method, which is why I installed 500A Blue Seas remote controlled contactors for each of my 280A x 24v LiFePo4 batteries.

You might be able to get away with mixing sizes of LiFePo4 batteries and/or with different cable lengths, but I would never do that. It might "work fine" but you will overworking one battery and underworking another, not fully charging one or more which screws with the cell balance, etc. etc. Just ick. It would be better to discharge disparate batteries sequentially, rather than paralleling them, provided the draw does not exceed 0.5C or whatever your batteries are happy with (EVE want you to do no more than 0.5 continuously).

LiFePo4 cells have vastly greater power density by both weight and volume than lead, so it should be easier to avoid having to put batteries in different places, than with lead. I was able to fit 13.5kWH of battery capacity in a single one of my two battery box positions, in a place which held only 5.4kWH nominal and only 2.7kWH usable capacity in lead (4x Trojan T105's). Not only did I get 16x EVE 280K's in that space, I also got the BMS's, contactors, bus bars, fuses, and other paraphernalia.