Easiest way to mount a Class T fuse

[Asthix]

I'm planning a simple installation with a 48V DIY Battery case(Apexium) connected to a Victron multiplus.
There is already a regular 400A fuse in the battery box but i absolutely want a class T.
I'll put a circuit breaker in between for easier disconnection.

Where can i install the class T fuse, as i know the closer to the positive terminal, the better it is.

I've seen some people put the Class T between the 2 row of cells, is it even a good idea to do it that way?

 

[yabert]

I've seen some people put the Class T between the 2 row of cells, is it even a good idea to do it that way?

If it's an advantage, why not. His important function is to cut the circuit and a fuse anywhere in the circuit will cut it (if properly integrated).
After all, many EV battery have their main fuse in the middle of the pack.

 

[Drizzt321]

I've seen some people put the Class T between the 2 row of cells, is it even a good idea to do it that way?

In theory, I suppose. But generally the approach is to put it as close to the positive terminal coming out of the full pack as possible. As for how to mount it, I'd recommend in an appropriately sized fuse holder. There are ranges of Class-T fuse amp handling and each range has it's own different physical size. So for example a 50A fuse won't properly fit in a holder for a 150A fuse, and vice versa.

I recommend the BlueSea Class-T fuse blocks https://www.bluesea.com/products/category/16/73/Fuse_Blocks/Class_T_Fuse_Blocks But there are other quality brands too. Just be careful about buying generic stuff off of Amazon. Sometimes, often, it might look thick, but it might be plated brass instead of plated copper or the like. And make sure to get one with a cover, to avoid accidental bumps or what not. I'd get one with studs with a bolt to hold down, rather than the style that you stick the wire in and screw a terminal down.

And you don't need a circuit breaker for a disconnect, any of the decent brand switches, as long as it can handle the continuous and spike current, will be fine.

After all, many EV battery have their main fuse in the middle of the pack.

Is it in the middle of the string of cells? Or it just so happens that the final terminal(s) for the string of cells is in the middle of the pack because they designed it that way? I honestly don't know, I haven't examined any of the EV packs in any sort of detail.

 

[yabert]

Is it in the middle of the string of cells? Or it just so happens that the final terminal(s) for the string of cells is in the middle of the pack because they designed it that way?

They generally design the pack to have the main fuse or pyrofuse in the middle of the pack.
At both end of the pack (main + and -) they put contactors.

 

[Drizzt321]

They generally design the pack to have the main fuse or pyrofuse in the middle of the pack.
At both end of the pack (main + and -) they put contactors.

Interesting, so they specifically put it middle of string. *shrug* Probably a good reason for it I'm not thinking of, and I can't think of a specific reason why it technically wouldn't work the same as at the end of the string.

 

[robbob2112]

It has been debated a few times... the reason not to do it is putting a fuse between cells 8 & 9 the fuse has increased resistance over a bus bar or wire. That is heating right at your cells when you pull current and a slight voltage drop on the fuse... were it me I would put it on the positive side hooked with short wire to the positive terminal.

 

[GuyG]

I recommend the BlueSea Class-T fuse blocks

Good brand. Their 5502 model will accept a Class T from 225 amps up to 400. The identical product, btw, is offered by South Bend Components for about 2/3 the price of BlueSea. And I mean identical. I once ordered both of them and compared them side by side. Indistinguishable.

 

[Drizzt321]

Good brand. Their 5502 model will accept a Class T from 225 amps up to 400. The identical product, btw, is offered by South Bend Components for about 2/3 the price of BlueSea. And I mean identical. I once ordered both of them and compared them side by side. Indistinguishable.

And same material inside the coating, near as you can tell? What's their website?

 

[GuyG]

Damn, they’ve gone up a lot since I bought it last. But still cheaper than the Blue Sea branded one.

Amazon.com