With all the thingamajigs and electrical stuff that I am installing in the car, I decided to mount a battery cut off switch, a few master fuses, and also, for the current measurement, a 500A shunt.
I will be running 3x20mm2 wires in the car for everything, which by my calculation is more than enough, and also two wires 16mm2 for the winch and 20mm2 for the starter and alternator. Winch, starter and alternator share a massive truck fuse, and the rest of the three wires have their own separate fuses.
For this kind of things, I usually do a CAD drawing, and than get a steel sheet, laser cut and bent, but since I wanted to speed things a bit, I decided to wing it.
I know I will want to install a bunch of stuff under the bonnet, so I decided to squeeze everything in a really small enclosure. Here are the first mockups:
I went to a local shop and had a piece of steel sheet bent.
I drew the drilling patterns.
This tool is really handy, it puts a bunch of stress on the electric drill, but it works.
I realized that the whole box needed to be angled to align nicely with the battery box, so I created this gap.
After MIG welding there was no gap, only a nice angle.
Rivet nuts are great. I use them all the time.
See, all nice and pretty.
I needed to make a mount for the pull cable, a leftover of the roof rack was ideal for that purpose, of course after some modification.
All ready for sand blasting and powder coating.
Battery box also got on the schedule. After bunch of experimenting, I decided where I want the holes to be drilled.
Marked and drilled.
I usually use a kitchen sink punching tool for these holes, but this time I borrowed this hydraulic punching press. Basically the same thing, the only difference is that instead of a ratchet and a bolt you are pumping the hydraulic cylinder, which is faster and easier.
Also the edges were welded.
I needed extra support so I used two steel rods and re-purposed a failed attempt of making an air solenoid bracket.
This weld won’t win a beauty contest, but it serves the purpose.
Of course I couldn’t live with welds like that, so here’s some more welding and hand filing until it looked good enough for me.
Also, I bent a piece of a wire, cut it in half, and welded to create the fastening bracket for the battery.
After that everything was smoothed out with the biax tool.
All ready for sandblasting and powder coating.
One of the mockups during the build.
Battery box sandblasted.
Fuse box was also prepped for powder coating.
After powder coating the assembly has begun.
Here is a 500 A shunt and a master fuse box for the starter and a winch.
Eye fasteners had a weird design, so little hand filing was in order to fit the contacts inside the fuse box.
All nicely crimped.
The next step was to put some electrical tape on the transitional area and wrap it inside the snake skin.
Another layer of electrical tape. Actually I was using and managed to squeeze 20mm2 cable inside the 16mm eye fastener. Even 16mm2 would be enough for the electrical system, but I already had 20mm2 cables so even better.
And the last part – shrink wrap insulation with integrated glue for a nice and clean look.
For the main ground, and also master positive line I used a 50mm2+ cable.
Everything was crimped in place.
An insulation tape, a snake skin insulation, an insulation tape and a shrink wrap with integrated glue over everything. Try to say that three times in a row.
Shrink wrap placed. I also put a piece of electrical tape so I don’t heat damage the snake skin insulation with a heat gun.
Shunt was couple of mm to large for the enclosure, so I needed to cut it a bit.
Also the hole was hand filed, so it can have a proper contact with the eye fasteners.
Shut off switch resistor was also wired, and insulated with a bunch of insulation .
Since shunt gives only a few mA of signal current, I decided to use a high quality copper shielded cable that was also wrapped in extra protection.
Signal cable all finished and ready for the installment.
Some more interconnecting cables were fabricated.
All the components installed.
In order to clamp cables properly, this cable sleeves have been mounted and crimped.
After some searching I decided to use those headless hex drive bolts for a cleaner look, and they worked like a charm.
Last thing was only to cut off the excess material, and to pull the rubber boot over the connector.
Here you can see the whole sleeve nicely distributed inside the battery clamp.
A completed unit with all cables attached. Also the negative cable on the left.
You can see here the rubber bezel where the master positive cable exits the box.
Power cut off switch and a pull cable bracket.
The grey/purple thing is the mega fuse that is protecting the starter alternator and a winch, currently rated at 300A, but can be changed if needed.
Inside shot with the cover removed. Because of the tight fit I used those compact 90 degree terminals.
Fuse enclosures open, since I have the current measuring shunt installed after all the electrical systems are running, I can measure every individual power line and fine tune the fuse selection if needed.
Fuse enclosures closed.
Fuse box installed. You can also see the glimpse of the winch control box below. Next step is to neatly arrange and route all the cables to its designated place, and then we’ll update the post.
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