Battery disconnect switch amp rating vs system current draw

[Fredrickson]

I have some sort of parasitic drain on my batteries.
(I will look for what's causing it when I have time.)

I picked up two (inline) battery disconnects from NAPA.. thinking they could serve as a temporary fix.
These things --> https://www.napaonline.com/en/p/NW_785116

After taking them home, I took one out of the package, and it appears to be one metal part sitting on top of another metal bit, sandwiching a layer of non-conductive, thin, foam-like material as an isolator. (You can see the white insulator in the picture if you look closely.. It's to the right of the word "KEEP" on the knob)


When the knob is turned.. it screws down to make contact between the top part with the bottom part completing the circuit. (over simplified description)



It is rated for "500 Amp Surge And 125 Amp Continuous At 12 Volts DC".

Between the time the glow plugs are warming, as well as the starter's draw (particularly when it's cold)..
I think these might be underrated for use on the truck.

..am I asking for trouble by using these?

 

[Selahdoor]

I used them for years on mine with no problem.

 

[Fredrickson]

Hey @Selahdoor, these green knobbed do-dads?
My concern is some sort of heat build up.. then it melts the insulator.. and chaos ensues

 

[Selahdoor]

Yes. The very same connectors.

Make sure that you undo them more than a twist or two, when undoing them.

And make sure they are very firm when you tighten them back down.

Do that, and there should be no heat anyway. The heat in a connection like that comes from a loose or corroded connection.

I also smeared the actual connection between the two with a ton of silicone dielectric grease, which prevented corrosion.

 

[ifrythings]

You don’t need to disconnect the starter lead with this switch, these are really designed to go in between the battery and the main feed to the cab, just disconnect the 6/4ga wire that goes from the battery to fender starter relay and hook it to one post of the switch, then get a short piece of same size wire and run it from the other post of the switch to the fender starter relay. If you want you can take the glowplug power feed and put it on the battery side of the switch so your not pulling several hundred amps through the poor switch.

 

[snicklas]

I used the one from Hazard Fraught fo exactly what ifrythings said... doesn’t look like they carry it anymore..... but it worked fine for me.