Two quick questions...

[Al Skierkiewicz]

Oz,
Various outlets (car radio suppliers) have a product called spiral wrap. MCM sells it in various sizes and it simply just wraps around the wire bundle.
There is obvious diminishing returns with wire sizing. To halve the loss, you need to go to #6 (.00047 or approx. .0005 ohm/ft.) which becomes a problem with weight (more than twice the weight) and drawing the larger diameter through a structural member. In the above example you would drop 0.2 volts instead of 0.4 volts. There are many other losses in the system so the electrical design must minimize those losses within reason. A warm battery will have higher resistance and a cold battery will not be able to make enough chemical reaction to produce full current. (old northern trick in winter is to turn on headlights for 30 seconds to get battery warmed up before asking it to crank at 0 degrees.) Connector resistance adds up (two for each connector) especially if the crimps are bad or the connectors are loose. Each circuit breaker adds a little and the speed controller is not perfect, it represents about four feet of #10 all by itself.

This is an article about batteries in the White Paper section....
http://www.chiefdelphi.com/forums/pa...le&paperid=366

[Gdeaver]

We have not had problems with the power harness wires. We have had problems with sensor wiring and pwm cables. Therefore I would not have a problem with fishing power cables through structural members. Any digital or senor wiring needs to be replaceable fast. We have used 1" PVC wire race way for wiring. Pop the cap off and wires can be replaced easily.

[Nitroxextreme]

i can see alot of people have answered the resistance and power loss problem...now onto the connectors i've herd of many different types of connectors, stickers, etc. All i can recomend is zipties if you have enough. They work great for our team. We just attach small ones around the wire at random increments and at the ends.

[Ian Curtis]

If you plan to run lots of wire through the frame, be prepared to err, have fun, if something comes loose and it requires the changing of a wire or removal of the board. Been there, done that, not fun. Also even though you said to not pay attention to weight, wire does add up. We saved nearly 3 pounds in wire last year. (And it wasn't even thick stuff)

[John Gutmann]

our team saved half a pound by just getting shorter pwm cables and other high gauge wires

[mechanicalbrain]

Funny how this is called two quick questions yet its anything but that. OK during the clash our power wires got pulled out from the power connectors (the big copper ones that have a screw to hold the wire). My team leader wants me to solder the cable into the connector but I'm 95% (rough estimate) sure that it would be illegal. Yes the screws were tight and yes we used shrink wrap but as i understand it the cable got yanked right out. Can i get some confirmations on the soldering thing and if anyone knows any rules in specific I would appreciate it. Also if i need to make some PWMs run a good distance (4ft) should i just connect one, with a S bend in the wire so the connector can't be pulled, on to the next? Thanks all.

[BrianBSL]

Originally Posted by mechanicalbrain

Funny how this is called two quick questions yet its anything but that. OK during the clash our power wires got pulled out from the power connectors (the big copper ones that have a screw to hold the wire). My team leader wants me to solder the cable into the connector but I'm 95% (rough estimate) sure that it would be illegal. Yes the screws were tight and yes we used shrink wrap but as i understand it the cable got yanked right out. Can i get some confirmations on the soldering thing and if anyone knows any rules in specific I would appreciate it. Also if i need to make some PWMs run a good distance (4ft) should i just connect one, with a S bend in the wire so the connector can't be pulled, on to the next? Thanks all.

AFAIK, there's no rule against soldering the copper lugs, but you will need a pretty good iron to get it hot enough. We did it on all of ours, as I don't really trust or like those connectors but the rules say we must use them, so we'll make the best out of what we have. Of course, I don't think anyone is going to stop you at an offseason from using the non-kit connectors, and who knows what the rules will be next year.

[EricH]

Originally Posted by mechanicalbrain

My team leader wants me to solder the cable into the connector but I'm 95% (rough estimate) sure that it would be illegal. Yes the screws were tight and yes we used shrink wrap but as i understand it the cable got yanked right out. Can i get some confirmations on the soldering thing and if anyone knows any rules in specific I would appreciate it. Also if i need to make some PWMs run a good distance (4ft) should i just connect one, with a S bend in the wire so the connector can't be pulled, on to the next?

OK, I did a rule check in Section 5 and the only thing I found was that you had to insulate the connection. Nothing about soldering. Just make sure that you can get the connectors off the battery terminals for shipping. Maybe Q&A can tell you if it's legal.

As for the PWMs, that's about how you'd do it, unless you made your own to lenght, which it is possible to do. (I don't know the procedure. Someone else probably will.) If you do several, use electrical tape around the joint.

[Al Skierkiewicz]

Originally Posted by mechanicalbrain

Funny how this is called two quick questions yet its anything but that. OK during the clash our power wires got pulled out from the power connectors (the big copper ones that have a screw to hold the wire). My team leader wants me to solder the cable into the connector but I'm 95% (rough estimate) sure that it would be illegal. Yes the screws were tight and yes we used shrink wrap but as i understand it the cable got yanked right out. Can i get some confirmations on the soldering thing and if anyone knows any rules in specific I would appreciate it. Also if i need to make some PWMs run a good distance (4ft) should i just connect one, with a S bend in the wire so the connector can't be pulled, on to the next? Thanks all.

Of course you can solder these connections. As a lead inspector, I strongly recommend soldering connections especially primary power. A large iron helps, but a trick many people do not use is "wet" the tip of the iron with a lot of solder before placing it against the connetor. Add more solder until you get a large surface area between the tip and the workpiece. This will insure max heat transfer. When you think the connector is hot enough, apply solder away from the tip (and the solder pool) and if it flows then continue soldering. Add solder to the end of the wire and the connector but don't add so much as to allow the solder to wick up into the wire under the insulation. This will cause a stiff spot in the wire that makes it bad for forming the cable when you need to. Allow the connection to cool before handling or trying to add heatshrink.