Has anyone replaced fusible links with fuses?

[Azca]

↑ no, a fusible link is NOT instantaneous. Fuses are NOT all the same.

Cheers,
George.

Thanks George, what are the time delay properties of the fusible links? Just curious.

On the fuses, correct fuses are definitely not the same, all are different. If you are speaking of fusible link vs a fuse, they are both engineered to melt at a predetermined value. All conductors, in essence, are a fuse, overcurrent protection is designed to stop them from fusing (opening).

Based upon my limited knowledge of fusible links, the insulation is one difference, not sure of the conductor metallurgy and how it was designed.

 

[sunrk]

Problem I see with replacing fusible links at the battery with actual fuses is the 'behaviour' of said devices. Fusible links and actual fuses are designed with particular characteristics and like any protection device they should never be operating 100 pct of the time near or close to their 'maximum' rating but can sustain that since a fusable device rated for X will always handle X.

When X is exceeded what happens next is what determines the effect of circuits and systems that the device is intended to protect.

I've seen people talk about replacing the fusible links with all sorts of things - various types of fuse and even small DC circuit breakers.

I agree that in the normal course of using an 80 the fusible links should never fail electrically but of course the effects of physical use of the vehicle cause degradation in other ways (NVH transmits to all parts of a vehicle).

Fusible link - Wikipedia

en.wikipedia.org

For my 80 (a 1hz diesel) the OEM fusible link assy is 90982-08267.

 

[george_tlc]

Fuses, breakers, fusible links will blow or trip with some time delay that gets shorter the higher he over current situation. Some fuses are called fast blow or slow blow as a hint to their fusing action. Fusible links are basically stranded wire that is sized to fuse/melt at a certain current and contain the wire in a silicone jacket to contain the melted wire safely. Since a fusible link is wire, you can check online for the melting time characteristic at various current levels.

Cheers,
George.

 

[Azca]

Some information on Links: All About Fusible Links | Allied University - https://www.awcwire.com/allied-university/informatic/fusible-links
Long but interesting document on fuse characteristics that is a good starting point: https://www.littelfuse.com/~/media/...nd_consideration_factors_application_note.pdf

The second link/document illustrates why just selecting any fuse or breaker to replace a fusible link is far more difficult than just looking at amperage. (Also, very important, this applies to AC wiring in the business and home, just plugging in a fuse or breaker because it fits or has the right amperage can be a HUGE safety issue!) Things to consider include, but are not limited to:

• A load study of the vehicle or circuit to be protected
• Time current curves and overcrurrent protective device (OCPD) properties in relation to the loads
• Temperature in the engine compartment (impacts the OCPD and selection greatly)
• Elevation (yes - this too plays a role)
• Location of the OCPD in relation to the conductor or systems to be protected (temperature difference between points)
• Size to protect the equipment downstream, not just the wire
• Withstand rating of the ocpd and/or fuse holder
• Durability
• Reliability

I did a little reading on links and many of the suppliers and manufacturers correctly note that just replacing the wire is not an accurate solution, these links are engineered, not just thrown in the system. Toyota's electrical engineers made a determination that the links, for this application, were the most reliable and dependable solution for the system for the masses who bought and used the vehicles. They engineered the link to properly protect the electrical system and made it "easy" to replace if they opened.

I still like fuses but, as stated before, it takes a lot of work to properly select a fuse size and type for an application. It is not nearly as easy as it appears and Toyota already has a solution. I still may jump down that rabbit hole in the future but, I have far more important things to do to my rig now, it has been sitting in the garage for 2 years as I try to break away to finish up the mods I started.

So, can you improve what Mr. T has done? - Yes. How hard is it? - If you are an automotive electrical expert, probably not too difficult. For the vast majority of the rest of us and do it right? However, that is just my opinion...