Would the surface area help with higher loads? Sc 4x4 4 pole type loads

If my test is accurate which I think it is then the resistance would need to be lower to help. Equal or higher will create the same amount of heat.

I wish I had more time to test stuff like this but between batteries and motors and operating SMC my time for testing is limited. I do have some different 5mm male connectors that I can try. Some guys really like the XT60 connectors and these are 3.5mm so maybe bigger connectors aren't doing much.

If I figure something out I will be sure to post it. As mentioned in my post I tested this 8 months ago as I was thinking it could make for better performance but my test at that time revealed it didn't.

I'm sure a pack with 5mm connectors will run fine as 0.20mOhm isn't a big deal but this isn't an improvement over 4mm connectors.

What MICK33B4 is saying has some merit. if the frictional force that resists insertion of the male connector is the same between the 4mm and 5mm, that will mean the load per unit surface area in the plug is lower in the 5mm plug because obviously a 5mm diameter cylinder has more surface area than a 4mm cylinder. So if you were to look at any given 1 square millimeter surface on the interface, the 5mm plug would have 4/5 the load on that area. Perhaps that is why it reads slightly higher in resistance. If you could make the interface between the male and female 5mm plug parts tighter you might see that resistance drop a bit.

To make a long story short, if pressure due to a tight fit at the interface has ANY effect at all on internal resistance (which is what I believe causes some internals to heat to the point of melting cases) a larger plug will require a proportional increase in insertion force to achieve similar resistance values.

I know my low profile male tips have a cross-cut relief in them that you can spread with a hobby knife to keep the plug fitting snug, can you perform the same on the 5mm plug and test IR again?

P.S.- Surface finish of the plugs can also have an effect.

P.P.S.- Just got my 4670 pack today, wasn't expecting it until tomorrow. Thanks a bunch for the flawless RC shopping experience.

The only reason I see the thought of 5mm bullets being a good one is if 4mm bullets got warm in use. Bigger connectors can probably handle more current, and possibly have more heat disipation, so under normal use after a run the IR could be lower (lower connector temp) but I've never had a 4mm get warm, so this idea is probably a waist of air

Actually the 4mm adapter has been used allot and the gold plating is not as good looking. The 5mm is brand new. I need to push them in fairly hard so they both feel tight.

When I have more time I will do some more testing by using a different 5mm male connector.

Thanks for the nice comments. We do try our best to satisfy our customers.

I guess when I said finish I was thinking surface roughness which is a measurable property. A used terminal should actually have a smoother surface roughness and potentially better contact than new (assuming all else is equal) due to the wearing down and smoothing of the surface features in the tube.

These are just thoughts. The Proof is in the testing.

Kudos on your efforts to bring accountability to a hobby in dire need of it.

After reading the posts about pressure it made me want to test different connectors and I remembered I had a new EC5 male connector so I switched the previous 5mm connectors I tested with the ones from the EC5. I noticed that they were harder to press into the female tubes. I also decided to put some new 4mm male connectors. These also felt a bit harder to press in but maybe not as hard as the 5mm.

EC5 5mm IR: 5.56mOhm

New 4mm : 5.60mOhm

Guess the contact pressure does play a role in all of this. I always knew you want your connectors to fit tight but the previous 5mm and 4mm weren't what I consider loose. In conclusion I guess that 5mm and 4mm are very similar in resistance.

I see that the difference in IR went down, but do you recall what the IR values were on the previous test? I'm curious if both 4mm and 5mm saw a drop in IR. If so, this definitely would indicate plug stress(pressure) is a factor. If the values are close to the same as the first test, I would be inclined to think the surface conditions in the plug are also playing a role, whether it be surface roughness or plating/finish integrity.

Two tests is really only anecdotal evidence, though. It would probably take some time and use of the two types to make a sound conclusion.

Still very interesting.

The IR is higher as the cell was cooler. A cell will change in IR if the temp changes. Initial test was done at 74 degrees and the second test was done around 72 degrees.

The fact that the 5mm now has the same results as the 4mm seems to point out that it is due to pressure as the first set of 5mm did go in tight but the ones from the EC5 really needed to be pushed in with more force. My older 4mm adapter provided higher IR than the new one as the new one required more pressure to push it in.

I can't imagine a 5mm connector needing more pressure than the new 5mm from the EC5 connector. I assume it's safe to say this is as tight as you could go unless you want to use a hammer to plug them in and pliers to pull them out. This means that as far as resistance goes the 5mm connectors have no advantage over the 4mm. I think if racers want to reduce resistance they would do so by using bigger and shorter wires. In fact I plan on doing some wire testing in the near future. I did do a test on wire length awhile ago and it was very interesting. I will do a new test with 12 and 10AWG and measure the resistance at different lengths.

For now I will not be investing in new molds for 5mm inboard packs. If our customers feel they need this then I guess we will have no choice but at this time I see no advantage in performance plus this would add some weight to the pack.

There is this website that offers a wire resistance calculator based on wire gauge and length.

http://www.cirris.com/testing/resistance/wire.html

The basic calculator at the top of the page will calculate resistance of any gauge or length I've put in, even though the graph below it only goes to 12 ga.

There is an advanced calculator link at the top of the page just below the simple calculator that gives more options. If your results are similar to this I would suggest not wasting the time. If you have different results then I would like to see them. See if all of the claims of "high quality wire" running around the industry are founded or not. It would also be interesting to see how much a role the number of filaments in a give wire gauge change the resistance values.

I'm sure that the quality of copper in the wire will effect the results, though.

Sorry, that sight only does wire by the foot, not inches. Disregard the link.

I did the test on a cell and doing discharge tests using the voltage sensing leads at the cell and 2 different lengths. You can see this test on the SMC Facebook page in the photos section and then Albums. You will see a cell and with wires and how I did the test. I didn't have the ESR IR meter at the time of the test.

I will take a cell and put some 12 and 10AWG on it and then measure the IR at the cell and at 6 inches and 12 inches and see what the difference is. Not sure when I will have time to do this test but as soon as I do I will post the results. What is interesting is that I know when a cell has 0.40mOhms higher IR that it will result in 0.02 lower voltage under a 35 amp load. I think racers who race in classes that need all the power under estimate the size of the wire and length of the wire.

Yet another great showing for SMC at LSR Speedway. Qualified 3rd and finished 3rd.Being the last shorty pack holdout in Sacramento I was up against some serious fast guys in 17.5 buggy. Single lap record was 17.4 heading into yesterday's club race. While I personally didn't set the fastest single lap of the night, 3 of us went faster than the previous mark. The mark was set at 17.1 and yours truly went 17.3 6500 premium certified holding it's own against the shorty packs of other companies. I guess play time is over and I will shed about 90grams and start running the 4600 packs and turn these 17.3's into 16.8's Thanks to Danny for the awesome packs.

Today i took home the tq in the a main with the 6500 2s pack in my 2wd ft sct great pack. i love these thing i told a couple of people about them. cause they like how great i looked out there with it. the first race i came in 3rd then the rest were all first place i cant believe i finally got the number one spot it feels so so so good.