House battery frame and venting, Post 3
In the last post I showed a copper bolt attached to the van floor that was going to be used as a grounding point. A couple of people pointed out that the bolt should also be grounded to the frame. That made sense so in the last couple of days took care of it. And surprise, surprise. I have pictures!
Ordered a two foot length of 1 inch wide flexible grounding strap from McMaster-Carr. It's $4.80 per foot. Listed as comparable to 1 AWG. It's probably overkill but at that price, why not.
Once more unto the breach, dear friends. It's back under the van I go.
You can see the copper bolt on the left. I want the grounding strap to run from it to...
...the frame beam here on the right. The bolt end won't be a problem but the frame end will. One problem is the emergency brake cables. Nothing I add should interfere with them.
Another problem is that the gas tank is right up close to the other side of the frame beam.
And on the inside of the beam are vent lines that run to the emissions canister. Between the vent lines and the gas tank It's impossible to get my hand up behind the frame beam to do any work.
Need an anchor point for the frame end of the grounding strap. With the gas tank and vent line in the way, drilling a new hole is out of the question. Have to make use of one of the holes already in place.
This picture is looking straight up from under the van. The best candidate seems to be the slot you can see to the right of the painted over bolt.
By the way, thought of using the painted over bolt but once I got to working on it found it so rusted it would probably shear off before coming loose. Then I'd have a new problem so let it be.
The slot is just big enough, and I do mean just, to get a small length of angle iron through. Use the angle iron as backing for a nut. Slide it through the slot then rotate 90 degrees. This will hold the nut in place. That solves the problem of not being able to get my hand back there. Cut and drill the angle iron then weld on a nut for a 3/8" bolt.
Prep the ends of the grounding strap. Cut out a strip from a piece of .0162" thick copper sheet I had on hand.
Wrap the copper around the strap then crimp the end.
Fold over the crimp.
Apply flux to the end of the strap where it enters the copper end. Use a propane torch and solder to seal where the two meet.
Drill a hole for the bolt and do a test fit under the van before trimming the strap length. Then do the other end.
Want to make sure there is good electrical contract to the frame so need to do some work around the slot. No room to get my usual favorite metal cleaning tool, angle grinder with wire wheel, up in there so used a flat bastard file instead. And yes, it's really called that.
Took some upside down elbow grease but I got all the old undercoating and rustproofing from around the part of the slot that the strap will contact.
Next used sandpaper to get a clean surface. After that it was as simple as bolting each end in place.
OK, that last line was a lie. When maneuvering the angle iron with the welded on nut into place it fell in between the beam and the vent lines. Much cursing ensued. Luckily one of my tools is a magnet mounted on the end of a goose-neck style rod. Even with that it took at least 15 minutes to fish it out.