How To Build a Cheap Traction Circuit

[williamson]

Circuit breakers are Airpax, 500 amps,, $175, at KTA services. But I must admit I don't see the need, as the fuse is called a "semiconductor" fuse. Let me tell you, that doesn't mean that we are passing 775 amps thru a semi conductor! That's SEMI! It means it was designed to protect semiconductor equipment, which can be damaged by a spike. So the fuse will blow quickly. The circuit breaker has a trip time, depending % overload. So does the fuse.

[williamson]

The Albright contactors: If you want to use one, they are more expensive than TYCO. But, first go to the Albright web and see how they rate it for Amps, not the rating published by the seller. The same goes for the rated voltage. I've seen 120 volt rated Albrights rated for 165 volts by a seller. Don't buy it, if you have over 120 volts.

[williamson]

I think this post is important: there are usually 2 types of people building electric cars: Auto mechanics, or electronic technicians. I will post a typical schematic. An auto mechanic may ask for a physical drawing of what he should build. ASK!. there are as many variations of circuits as there are cars. Ask what you want to do. An electronic technician can modify my schematic to fit his car.

[williamson]

The copper lugs must be crimped on the welding cable. There is a preferred cable: this is one with very many very small wires. This makes the cable more flexible, and therefore, easier to bend into a cramped space. Luckily, the cable from Revolt-evc.com, recommended above, is this type. The cheapest crimper is a "Hammer Crimper". Electromotive sells one for $35.00. EV america.com rents a real crimper. This company is run by Bob Batson, maybe the #1 guy in electric cars. I bought a hammer crmper for $18.95 on ebay. He has plenty more. The seller was "super-genious", at e-mail: mark@sunmarcinc.com

[williamson]

The above site has instructions you can download and print on how to use the crimper. Very clear!! I didn't publish the ebay item # because that may expire. Search.

[williamson]

More on crimping: Before you insert the cable into the lug, you put some corrosion prevention compound into the lug. Home depot sells Noalox. I think thier SKU is 498-101. A 4 oz tube. The connection is then covered with heat-shrink tubing. A 2-3 in piece will do. You can buy the tubing with meltable sealing glue already inside. Revolt sells the lowest cost tubing. No glue. You can coat your connection with 3M #5200, fast curing, then the tubing, then the heat.

[Ryland]

Instead of buying a crimper or using a sub par hammer crimper ask around and you will most likely find an electrician who has a real crimper that either does a round or hex crimp, hammer crimps just put a dent in the round lug to keep them on the cable, round or hex crimper's shrink the lug creating a pressure weld between the lug and the cable, took 15 minutes to crimp 6 cables and they didn't even charge me, next time I need cables crimped I'll brig them beer.
I suggest cutting all of your cables to size, strip the insulation off the ends and fit the cable ends on how you want them to be masking tape works well to keep the from moving until you get them crimped, this will save the person who is helping you time and increase your chances of having them help you out later.

[williamson]

Ryland is 100% right, above. I wrote "cheap traction circuit". Ryland has given us a better way. Let's add some light to this topic: We want 100% contact area between the copper bundle and the inside surface of the lug. That's the best we can do. So to accomplish this, we should evaluate the crimp to see how it complies. This means a crimp from one end of the interior of the lug to the other end. It also means 100% contact all around the copper bundle. This first part means that a hammer crimp would have to be made from one end to the other, multiple crimps. The second part means the lug has to be closed down all around the wire bundle, with no air gap. the bundle can be squised into an irregular shape, that's not a problem. When I do my test of a hammer crimp, I'll report back. Can any one post as to if a hammer crimp CAN accomplish most of this?? Another good result of Ryland's post is to call to everyones attention what is required of a crimp. Visually. Now you know what to look for! Thank you, Ryland.

[williamson]

A hydraulic crimping tool that does a hex crimp, requires you to use the right die-set for your cable size. Every connection under the hood (or anywhere) where it might get splashed, requires a water-tight cover. When you install heat-shrink tubing over a connection, you can use a hair-dryer to shrink it. The seller listed about 4 postings up, also sells a hydraulic crimper at a good price, on his store site. About $56 US. You can cut the power cable with a hack-saw. There is an excellent article on safety at:www.inc.com/users/evainc.html?111.

[williamson]

A manual safety switch is made. This cuts the power off. The only problem is that it requires running the traction voltage into the passenger compartment. I chose to have the pull-handle in the passenger compartment, just like the old-fashioned choke cable. This cable should be a nylon rope because it does not conduct. You could put a plastic carrying handle on the end, just like in dept. store heavy packages.