I was never pleased with using the Dean's ultra connector in high amp conditions. When I saw the BK 5.5mm connectors advertised for 200 amps, I had to get some to evaluate.
http://www.bk-electronics.com/catalo...oducts_id=1384
I have had now ordered two shipments of connectors from them and they are very prompt (1 week from order to receive on US east coast).
The first picture below shows the male and female connector from both ends. They may be considered heavy, 6g for a male-female set for one lead, while for comparison the complete Dean's ultra for two leads is 4.8g. But look at the second picture where I have cut off the recess end of the connector for the wire and soldered them directly onto a battery pack. Now you have lost the weight of extra connector material as well as the weight of the battery leads. Note in the photo I have some tape around the outside of the female post.
(Side question for you experienced F5B flyers who have been soldering connectors directly to batteries- should the male connector be soldered to the negative or positive battery post? I think I have it backwards as I have the male soldered to the positive post and it could potentially short to an object when one is carrying around extra batteries. The female post can be shielded with Kapton tape around the outside.)
Now for some science to check how good these connectors are. I took advantage the resources I have at work and used an Agilent 4338B MilliOhmMeter (4 wire resistance meter with resolution to 0.1 micro ohm) to check the resistances of various connectors I had laying around. The third photo below shows the connectors. The connectors are Deans Ultra, and then left to right in the photo: BK 5.5 mm, MPI Maxx 3mm gold plated banana, no name 3 mm gold plated banana, Astro Zero connector. The average readings from multiple connectors, multiple readings with separation and re-seating connector are:
units are micro ohm (per contact pair - i.e. single male-female pair)
Deans Ultra - 91
BK 5.5 mm - 111
Astro Zero - 190
MPI 3mm - 340
Generic 3mm - 360
These results for the BK 5.5 mm connectors are consistant with the results that Steve Neu has obtained. The 5.5mm connectors have about 3 times less resistance than the typical gold plated 3-4 mm banana. More importantly the 5.5 mm connectors have the "meat" where the thin spring leaves on the 3 mm banana's will loose their stiffness if they get too hot. Contact resistance is directly proportional to the contact force. Loose the contact force and the contact resistance starts to shoot upward.
enjoy
Don