Lithium Battery Box

[bigal.nz 61]

Anyone here built a battery box for Lithiums (looking at Victron)?

I have seen a design that was stainless, but having a big conductive box must be a bit of a risk - wondered if there is a better material to build it out of? Another person suggested marine ply, but I would be surprised if it meets the fire rating required.

 

[LBD 186]

2 hours ago, bigal.nz said:

Anyone here built a battery box for Lithiums (looking at Victron)?

I have seen a design that was stainless, but having a big conductive box must be a bit of a risk - wondered if there is a better material to build it out of? Another person suggested marine ply, but I would be surprised if it meets the fire rating required.

 

If I was having this debate with my-self... I think I would prefer conductive to combustible with possible toxic fumes... exercise caution where cables pass through and ensure  that the lid does not contact the terminals if stood on....

[K4309 405]

If you go stainless, I would line it with a flame proof lining / insulation.

The sound proofing foam I've got for my engine is rated as flame proof. I took a blowtorch to it and still couldn't get it to catch. Forget the trade name now, but it was the good stuff from a specialist supplier, not the cheap stuff from Burnsco. About 25mm thick. You can get it without the alloy foil lining, which would be a hassle. Nice and soft cushioning too, which may help to reduce vibration damage to the batteries.

Anyway, my point is you can build a good strong stainless box, and reduce the conductive risk by lining it with something both non-conductive and fire-proof.

Personally, I'd go for lead carbon batteries instead of Lithium, similar electrical charge / discharge characteristics, fraction of the price and you don't need a circuit board (BMS) to stop them exploding. But you didn't ask that question so I'll keep my thoughts to myself on battery type

[CarpeDiem 530]

4 hours ago, bigal.nz said:

Anyone here built a battery box for Lithiums (looking at Victron)?

I have seen a design that was stainless, but having a big conductive box must be a bit of a risk - wondered if there is a better material to build it out of? Another person suggested marine ply, but I would be surprised if it meets the fire rating required.

 

Taking into account you said victron and battery, I am assuming you understand that a victron battery is just a box with batteries (cells) inside it.. 

Why do you want another box? And where will the box be? 

Understanding why you want a box to put your batteries in to will help with material selection. 

[motorb 45]

Honestly, I'm waiting a few more years for the new sodium-ion battery tech to come into the mainstream.  It's got all the benefits of lithium with none of the fire hazard,  at only a slight weight penalty. It's already on the market so won't take long for victron etc to catch up.

In the meantime, I'll stick with my AGM lead acid. Saving 20-30kg isn't going to make much difference for me (and the weight is low down anyway).

 

OK, that wasn't helpful.... stainless is fine for a battery box assuming there's no chafing or shorting, but where is all the heat and gas going to go if it does burn? I'd also consider the situation with thermal insulation of the battery if charge and discharge rates are high and sustained, or conversely if it's too close to a source of high heat or freezing cold.

If the worry is loss of the boat and/or a fire on board, I've got to ask if lithium is really the most appropriate choice for anything but the lightest of racing craft. If it's just about managing the additional risk, then the steel box is only one part of your design consideration; location is also very relevant as that fire cannot be put out and will produce a lot of heat and hot toxic gas until it's done.

[Psyche 826]

I doubt that a battery box is going to help much to prevent fire, as the heat has to go somewhere but anyway I went down the rabbit hole of trying to find out what the legislation says with regard to lithium installations. My conclusion is that they really don't want you to know! How about $186 for a copy of the standard https://www.standards.govt.nz/shop/asnzs-3004-22014

 

[Zozza 357]

My understanding of all the Lithium style batteries, the Marine LiFePO4 are the least fire hazard of all, perhaps even less of a fire hazard than AGM or old style Lead Acid Golf Cart type.
Don't hesitate to put me right though - what I know about electrical things is less than Donald Trump knows about how Tariffs work.

[Frank 175]

14 hours ago, CarpeDiem said:

Taking into account you said victron and battery, I am assuming you understand that a victron battery is just a box with batteries (cells) inside it.. 

Why do you want another box? And where will the box be? 

Understanding why you want a box to put your batteries in to will help with material selection. 

The outer casing on the Victron Battery in our land yacht is  Aluminium ex factory , the electrical inspector considered that to meet the rules without further ado but I built an outer box in ply and lined it with several layers of dry fibreglass from a heat blanket (ex bunnings) . A lithium battery apparently can burn at close to 1000 deg C so aluminium will eventually fail although by that stage you might be in the raft anyway. I think a steel/SS light gauge folded angle frame with some sort of refractory lining or fire proof lining, plenty of options/products out there in blanket or sheet form. .

Question is what would you do if the battery caught fire (any battery not just lithium) ?

 

 

[bigal.nz 61]

Agree with most of what's been said on here. Namely:

1. You ain't putting out a Lithium fire;

2. The battery box venting holes have to be rather big, so its ability to contain is minimal - I think its more about buying time, potentially to evacuate.

No better materials suggested so far.....

Al

 

[CarpeDiem 530]

The latest installation standard applies to all batteries - not just Lithium.

Stainless Steel is the best option to meet the standard.

Battery compartments should be made of non combustible material, they should be corrosion resistant.

They should be mechanically or naturally vented to the outside with an air intake from below them that is also from the outside.

Structurally sound, well fixed in place.

Compartments should be sealed and completely prevent the ingress of fumes into habitual areas.  

I suggest that you only buy Lithium batteries that are IEC 62619 certified or at the very least batteries with cells that have the same certification.

While not currently in the the standard for boats, this is in the current standard for Caravans and Motorhomes, its a matter of when not if this gets to the marine standard.

Be aware that not all Victron batteries carry the same level of certification and only a couple of Victron models have the IEC 62619 certification.  

Lead Carbon and Sodium Ion are just as likely as Lithium Ion to result in disaster if they are not cared for.

[Psyche 826]

Yet for the entire history of yacht batteries in NZ they are in wooden boxes under a bunk with no outside vents fuming away under the squab usually. Number of FLA incidents compared to boating hours is infestiminal.

[aardvarkash10 1,114]

17 hours ago, Psyche said:

infestiminal

In-fes-tim-inal, adj, an infestation of extremely small battery problems.

See: extrarodentially and infesterminal