Blue Sea Systems Mrbf (cube) Fuses

[arthur49]

The following were recommended to me so I use them on my lithium batteries. 80A rated

Blue Sea Systems 5191 single 300A MRBF Marine Rated Battery Fuse terminal fuse block with insulating cover

Blue Sea Systems 5191 MRBF Single Fuse Holder Fuses shown for illustration purposes only - NO FUSES SUPPLIED Compact, high-amp fuse—appropriate for DC Main, inverter, windlass, and bow thruster circuit protection Provides high current protection in tight space constraints Ignition...

www.mobilecentre.co.uk

On a 47A load running for 5 minutes the fuse/assembly is too hot to touch.

With that load the voltage at + terminal on battery was 12.27v and voltage at the load end of cube fuse was 11.83v. ie 20.68W loss as unwanted heat!

Sounded like great protection to me when recommended but ............

The whole assembly is correctly installed and torqued and the loss is across the fuse.

 

[RichardB]

Oh that’s interesting. I was going to get a 250a one when I do my lithium upgrade but may just stick with a mega fuse

 

[Hoovie]

The following were recommended to me so I use them on my lithium batteries. 80A rated

Blue Sea Systems 5191 single 300A MRBF Marine Rated Battery Fuse terminal fuse block with insulating cover

Blue Sea Systems 5191 MRBF Single Fuse Holder Fuses shown for illustration purposes only - NO FUSES SUPPLIED Compact, high-amp fuse—appropriate for DC Main, inverter, windlass, and bow thruster circuit protection Provides high current protection in tight space constraints Ignition...

www.mobilecentre.co.uk

On a 47A load running for 5 minutes the fuse/assembly is too hot to touch.

With that load the voltage at + terminal on battery was 12.27v and voltage at the load end of cube fuse was 11.83v. ie 20.68W loss as unwanted heat!

Sounded like great protection to me when recommended but ............

The whole assembly is correctly installed and torqued and the loss is across the fuse.

not that unusual to have very hot localised areas - I used to get >100C on the connection to a 300A ANL Fuse Holder (actually distorted the holder with the heat so I changed to a Mega Fuse setup instead).
But that voltage drop across the fuse is not good at all.