8 kA Breaking Capacity Sufficient for LiFePO4 fuse? AMXL

[bestconcreteblock]

I am currently using an AMXL fuse ( AMXL Data Sheet ) for a custom 48V pack in a piece of mobile equipment. At 63V, this fuse is rated with 8kA breaking capacity. The small physical size of this fuse is main reason I am using it over other options with higher interrupt rating. Any thoughts on the 8kA breaking capacity in a short circuit situation?

 

[EnergizerNate]

If you only need one fuse, get a T-class.

 

[bestconcreteblock]

These are relatively small(60 Ah) power cells. The spec sheet list the internal resistance at 1.5 mOhm. 3.2V / .0015Ohm = 2133 Amps. Obviously internal resistance is not this simple, but even if I double that current, I still have a factor of safety of 2?

 

[ricardocello]

Better than most fuses in that size. Your battery internal math seems reasonable to me.
Are you running a 48V nominal system? Meaning you will see between 46 and 57V?

 

[bestconcreteblock]

Meaning you will see between 46 and 57V?

Right, so probably the fuse would have a little bit higher interrupt rating.

 

[ricardocello]

BMS with short circuit protection, or just bare battery?
LiFePO4 or FLA/AGM? Sorry, subject line said LiFePo4.
What configuration are the cells, 16s?p
You should calculate the overall internal resistance not just the individual cell resistance.

 

[bestconcreteblock]

BMS with short circuit protection

Yes, JK BMS

 

[ricardocello]

Yes, JK BMS

see updated questions above.

 

[ricardocello]

Thanks for showing these.
They appear to be superior to the MEGA fuses (2.5 kA AIC), and are much cheaper.

 

[bestconcreteblock]

Thanks for showing these.
They appear to be superior to the MEGA fuses (2.5 kA AIC), and are much cheaper.

Yeah, pretty affordable. They appear to be injected with some kind of silica filler, probably to extinguish the arc?

 

[bestconcreteblock]

see updated questions above.

16s. Looking at cell itself would be worst case I suppose.

 

[ricardocello]

16s. Looking at cell itself would be worst case I suppose.

if no cells or batteries in parallel, your calculation is correct.

 

[ricardocello]

Yeah, pretty affordable. They appear to be injected with some kind of silica filler, probably to extinguish the arc?

The electric vehicle market appears to have spawned newer products like these.
I don’t mind taking advantage of that for off-grid batteries!

Now we need fuse holders with 30 or 35.5mm bolt spacing for M6 lugs.

 

[bestconcreteblock]

Now we need fuse holders with 30 or 35.5mm bolt spacing for M6 lugs.

Yes, I had a nylon holder printed that holds two M6 coupling nuts(nylon is not part of the terminal compression stack).

 

[firemowgli]

Now we need fuse holders with 30 or 35.5mm bolt spacing for M6 lugs.

Did you ever find a fuse holder that fits the AMXL fuses? Seems like there is an HMX holder for the smaller AMX fuses but I cant find anything to fit that 35mm.

 

[ricardocello]

Did you ever find a fuse holder that fits the AMXL fuses?

Nothing. Maybe they are too new. I suspect because they are EV automotive fuses that standalone fuse holders aren’t going to be needed, they will make custom fuse holder assemblies for vehicles.

There are individual stud blocks you can buy and build your own.

https://www.mouser.com/ProductDetail/Bussmann-Eaton/C5268-4?qs=sv12qe8ZWxOLxsQFAFuhEQ%3D%3D&srsltid=AfmBOophcpUIRvx29FM3bT8Q5sDMnKGllqxGBGw2WRNyMKDLbFRN0gb2

The 1/4” stud may not fit the M6 (6.2mm) hole, however.

If you want beefier, Littelfuse has the LSCR001. $$
Same issue with stud size.

LSCR002

Littelfuse LSCR Series is a comprehensive line of modular fuse blocks, designed to accommodate a wide range of High-Speed and UL Power Fuses. These LSCR Series blocks have modular stud type design that enables easy mounting in panel boards. LSCR Series blocks are CE Certified and RoHS Compliant.

www.littelfuse.com

Hey, this is a DIY forum.

 

[firemowgli]

Hey, this is a DIY forum

This is true - I was thinking something like this could work. Get two per fuse and mount them in the right spot.

BSCR101 | DigiKey Electronics

Order today, ships today. BSCR101 – Fuse Block 500 A 1000V 1 Circuit Bolt Down Chassis Mount from Eaton - Electronics Division. Pricing and Availability on millions of electronic components from Digi-Key Electronics.

www.digikey.ca

But no cover... unless one could figure out a good way to cover

 

[SparkyJJO]

But no cover... unless one could figure out a good way to cover

Cut a soda bottle in half lengthwise and duct tape it in place

 

[firemowgli]

Cut a soda bottle in half lengthwise and duct tape it in place

 

[frankrudis65]

Cut a soda bottle in half lengthwise and duct tape it in place

Don't forget sand in it

 

[frankrudis65]

Here's another option @ aitefuse.com :I have chosen the 80VDC Telecom gS fuse (NH00) and the fuse switch disconnectors.This should solve the problems megafuse and co. have got with lighting-up your homes....