Battery Leads Coming Loose

[jee7s]

FRC 2789 crimps leads as well. We've found that Home Depot carries the Thomas and Betts line of compression lugs, and they work very well. If you do crimp, don't fall for any "heavy duty" language on the packaging...that usually just means a thicker wall on the lug and hence bad compression.

To crimp, we use McMaster# 7061K12 plus an arbor press (no, we don't hit it with a hammer to compress like the instructions suggest). If you go this route, make sure you crimp into and out of the face of the lug. Going sideways means you don't get the right geometry since you aren't pressing into the split part of the lug.

After crimping, we could solder, but we find it isn't necessary. We do heat shrink over the shank of the lug, but not over the whole connection.

To attach to the battery, we use a nut-bolt combination (McMaster# 91241A773 and 96278A411) that includes a spring-type lock washer and a toothed washer (both are captive so nothing gets lost). AND NO OTHER WASHERS! Extra washers on battery terminals may feel like a good thing to do, but in the end they just provide extra surfaces for slip to occur at, and that causes all sorts of bad news when vibration starts.

We've had a great deal of success with this, when the fastening is done correctly.

Also, if you get that crimp tool and some 6AWG wire (preferably welding cable style), then you can purchase the un-assembled APP disconnect from Andy Mark and make your own battery cables. Our BOM cost on these is about $6.75, which is less than half the cost of the pre-assembled cable. This also means you get just the right lengths for the run from the robot side of the disconnect to the main breaker and PDB. VERY CONVENIENT! (Particularly when done with welding cable)