ElectricSubaru


Last update: Oct 2 2017

Odds and Ends

Metric Bolts

Japanese Industrial Standard

Subaru uses Japanese Industrial Standard (JIS) size flange bolts throughout their cars. Most bolts in the cars are M6, M8, or M10. The JIS head sizes and pitch differ from the more common DIN standard sizes. The local hardware store likely stocks the DIN sizes only.

DiameterDIN Head WidthJIS Head WidthDIN Std PitchJIS Pitch
M610mm10mm1.01.0
M813mm12mm1.251.25
M1017mm14mm1.51.25
M1219mm17mm1.751.25

A JIS flange bolt kit is a good investment to keep the hardware in the car consistent, minimizing wrench swaps. A good source for individual metric fasteners is BelMetric.

Flange Bolt Flange Bolt Kit

Subaru Bolts

The information below can be used to find JIS bolts available from Subaru by size.

TypeJIS threadLengthCoatingMarkingNotePart
Hex boltM610Zinc010406100
Hex boltM612BlackWith phillips904740011
Hex boltM612ZincWasher attached. With phillips800506350
Hex boltM614Green7Washer attached901120069
Hex boltM616BlackWith phillips904740012
Hex boltM616ZincEFor electric ground904580002
Hex boltM620Yellow4010006200
Hex boltM630Zinc6800706480
Hex boltM816Zinc4010008160
Hex boltM820Zinc4010408200
Hex boltM825Zinc7B800608220
Hex boltM826Black8901000269

Rivet Nuts

Rivet nuts are a simple way to install threads to sheet metal or fiberglass panel. They have a clean high-quality appearance when installed, and look almost like the OEM installed them. Rivet nuts are particularly helpful for blind installations where you want to bolt something securely to a panel or frame rail and do not have access to the back side. The tool is a little tricky to figure out the first time. I recommend installing a rivet nut of each size into a scrap for practise and to use as a reference so you can see exactly how deep the threads end up. This makes it easy to select the right length screw. Thread sizes larger than M6 or 1/4in require the larger lever-handle tool, which can be awkward in tight spaces.

Rivet Nut Rivet Nut Tool, Small Rivet Nut Tool, Large

Nord-lock Washers

All bolts securing high current electrical connections should have Nord-Lock wedge lock washers installed to prevent repeated heating and cooling from loosening the bolts.

Nord-Lock Washers Nord-Lock Washers

Painting Aluminum

I prefer using aluminum rather than steel wherever possible in an EV conversion due to its light weight and machinability. One problem with aluminum is that if you paint it as you would steel, the paint usually rubs right off. I found the procedure below works very well to get paint to adhere to aluminum.

  1. Use fine emery cloth or a steel wire brush to remove oxidation and roughen the surface. Note that general purpose sandpaper is usually made with aluminum oxide, the very material we want to remove.
  2. Thoroughly clean using a rag soaked with vinegar. Wipe the aluminum until the rag picks up nothing. Let it dry. Continue as soon as dry to avoid re-oxidization.
  3. Spray U-POL Acid #8 Etch Primer.
  4. Apply the final paint. My favorite is Krylon ColorMaster Satin Black spray paint. Apply two light coats, then one heavy coat. The Rustoleum brand seems to wrinkle more easily than Krylon.

Emery Cloth Vinegar Self-Etching Primer Satin Black

12V Wire Selection

12.0 VDC With Maximum %2 Voltage Drop

1ft 2ft 3ft 4ft 5ft 6ft 8ft 10ft 15ft 20ft
1A 24AWG 24AWG 24AWG 24AWG 24AWG 24AWG 24AWG 22AWG 20AWG 20AWG
2A 24AWG 24AWG 24AWG 24AWG 22AWG 22AWG 20AWG 20AWG 18AWG 16AWG
3A 24AWG 24AWG 24AWG 22AWG 20AWG 20AWG 18AWG 18AWG 16AWG 14AWG
4A 24AWG 24AWG 22AWG 20AWG 20AWG 18AWG 18AWG 16AWG 14AWG 14AWG
5A 24AWG 22AWG 20AWG 20AWG 18AWG 18AWG 16AWG 16AWG 14AWG 12AWG
10A 22AWG 20AWG 18AWG 16AWG 16AWG 14AWG 14AWG 12AWG 12AWG 10AWG
15A 20AWG 18AWG 16AWG 14AWG 14AWG 14AWG 12AWG 12AWG 10AWG 8AWG
20A 20AWG 16AWG 14AWG 14AWG 12AWG 12AWG 10AWG 10AWG 8AWG
25A 18AWG 16AWG 14AWG 12AWG 12AWG 12AWG 10AWG 8AWG 8AWG
30A 18AWG 14AWG 14AWG 12AWG 12AWG 10AWG 10AWG 8AWG
40A 16AWG 14AWG 12AWG 10AWG 10AWG 10AWG 8AWG
50A 16AWG 12AWG 12AWG 10AWG 8AWG 8AWG
60A 14AWG 12AWG 10AWG 10AWG 8AWG 8AWG
70A 14AWG 12AWG 10AWG 8AWG 8AWG
80A 14AWG 10AWG 10AWG 8AWG
90A 14AWG 10AWG 8AWG 8AWG
100A 12AWG 10AWG 8AWG

Flush Rivets

When you need to fasten two pieces of aluminum and either space is too tight for a conventional fastener or you want a seamless cosmetic appearance, you can easily make your own flush rivet. Drill a hole 1/8in diameter through the materials where you want to join them. Chamfer the outside edges of the holes. Cut 1/8in diameter aluminum rod from the hardware store to a length 25% longer than the total thickness. While holding the two pieces together tightly on an anvil, hammer the rod until it is flush. The rod expands to fill the hole, flowing into the chamfers. After a little filing and sanding, the rivet is invisible.

Flush rivet Flush rivet Flush rivet Flush rivet Flush rivet Flush rivet Flush rivet

Electrical Connectors

An automotive electrical connector kit is a must-have item when converting a car to electric drive. Two popular connector systems are the Delphi Weather Pack and Metri-Pack. The best source I found for connector kits is MJM National on eBay.

Connector Kit

Delphi Weather Pack connectors are widely available, inexpensive, accommodate a large range of wire sizes, 22-12 AWG, and carry up to 20A. The best Weather Pack kits are at DIYAutoTune.

Weather Pack

Delphi Metri-Pack 150 connectors are slightly more compact and modern than the Weather Pack. They accommodate wire sizes 18-16, and carry up to 14A. Both sealed and unsealed versions are available, although the unsealed are difficult to find. The JEGS Unsealed Connector Kit has 1-4 and 8 pin connectors. The 6 pin connectors are available at Mouser, part numbers 15396848 and 15396849.

Metri-Pack 150
Metri-Pack 150