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Old Nov 12, 2009, 11:35 PM
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Mark's Connector Test 2009

Ok, show of hands...

Who knows what I'm up to here and who wants to see the results?

Mark
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Old Nov 12, 2009, 11:47 PM
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Xpress..'s Avatar
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Uhh, you're going to send 40 volts and 100 amps through them for an hour to see which one melts last?
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Old Nov 13, 2009, 01:54 AM
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Was bored tonight so I decided to test 4 of the more popular (in the US anyway) connectors that are used for battery to ESC connection.

From left to right in above photo:

1. Faux 'Deans'.
2. New HC XT60's.
3. Real Deans.
4. Anderson Power Pole (aka Sermos)

All connected via tin plated 14ga bus wire. First three are soldered. APP is crimped with WMR crimpers.

Leads on DMM are maintained at a controlled spacing (2.0") via popsicle sticks. Dumped a known current (10A) through the whole chain and then measured the voltage drop across each connector. From there, the power loss for each connector (and a little wire) can be easily calculated. (poor man's 4-wire kelvin meter )

The results were somewhat surprising, to me at least.

Drumroll.....

The worst of the bunch was the faux Deans which came in at 6.2mV of drop at 10A. Calculated resistance is .62 mOhms.

In third place was the new Hobby City XT60 which had a resistance of .58 mOhms. This one really surprised me as I expected it to do much better.

In second place was the crimped APP which had a resistance of .41 mOhms.

Top honors went to the real Deans which charted a resistance of .35 mOhms.

While only a sample of one and not a scientific test by any means, the differences between the connectors in typical practical usage is negligible and the end user would not be able to note any difference in flight performance.

Example - At 50 amps, the difference in resistance (.27mOhms) between fake Deans (worst) and real Deans (best) would result in an additional power loss of about 1.4 watts. In a 1000 watt system, this is a .14% difference. Granted that the additional voltage drop would result in slightly lower current draw but the point remains and anyone who thinks that they can 'feel' this difference is cuckoo.

Lesson here is that unless you are drawing tremendous current (>100 amps) for an extended period of time that would result in undue heating due to voltage drop, pick the connector that you prefer but understand that there will be no noticeable difference in performance.

Let the rocks fly...

Mark
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Old Nov 13, 2009, 02:41 AM
Passion
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Nice and interesting test. I also thought the XT60 would fare better, but like you say the difference is not that big. Would like to se a bigger test sample with different current setting up to 100A.

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anyone who thinks that they can 'feel' this difference is cuckoo
Exactly what I am saying on a lot of RC subjects.
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Old Nov 13, 2009, 06:37 AM
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I'm getting a bunch of cells, which I will us as input so I can draw about 150Amp without too much variance on the input, I gonna test about same connects are you have above too, in high amp sitiation to actually see how hot they get.
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Old Nov 13, 2009, 07:52 AM
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Haralson County GA. USA
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Well it is obvious that something is wrong here and that the test needs to be conducted over and over until the results match the popular consensus which your's does not.

I have read post after post about the ones you tested the Crimped APP is the best by far. Some have even stated that even a soldered APP is better that a Dean's Ultra.


Upon closer inspection I note two problems with you testing. Having the array laying on carpet ,which by the way look just like mine, is possibly inducing some additional random electrical paths and that you connected them all in series to make it simpler and only tested at one level..



Mark I conduct connector tests with every battery test discharge I run and their have been more than a few. I know which connectors get hot and at which power levels. I have tried to point out that APPs are not as great as most seem to think but most do not want to hear it. Good luck with the masses.


Charles
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Old Nov 13, 2009, 08:01 AM
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Nice job Mark,
If you do it again I'd be real interested in how a mini Deans performs in relation to the others. I've been using them in all planes with less than a max 20A draw and have not noticed them getting warm. It would logically seem that they shouldn't be performing that well.
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Old Nov 13, 2009, 08:28 AM
Passion
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Charles,

Have you tested the XT60 connectors? I would like to get your opinion on them and how you rate them compared to deans.
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Old Nov 13, 2009, 09:05 AM
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Appreciate the comments guys.

I did this test to placate my own curiosity for the most part and while a larger sample size is required to provide statistical significance to the numbers, this test told me that the above connectors are effectively identical in terms of real world performance for 99.9% of us whose planes draw less than 100 amps and a few 1000 watts. It's also my firm belief that any results that deviate significantly from the above would be attributable to either defective connector or improper termination be it bad solder joint or bum crimp.

Note that after the resistance of the bus wire is tared out, the real Deans has the effective resistance of an equivalent length of 13 gauge wire, which is pretty impressive. APP is roughly equivalent to 14 gauge wire. The remaining two are just slightly worse than an equivalent length of 16 gauge wire. Once again, none of these are going to be readily discernible from one another in a typical application.

Now if I only had a machine that could do a few thousand mates and demates, we could see how each of these perform over time. Maybe I'll see if the neighbor kid needs to earn a buck...

MrMel,
Would be curious to see the results of your 150 amp test. A burst test with periods of lower current draw would probably be most telling as I know of precious few who draw that kind of current for an extended period of time.

Charles,
Test was actually performed with the whole mess hanging in free air above the dielectric surface of my charge 'bench'. My lovely carpet was merely the backdrop for the photo before testing. As mentioned above, I agree that more samples are required to lend more weight to the numbers but I felt that testing half of the connector would tell me all I wanted to know and that I could simply double the voltage drop number since both halves within each connector are physically identical with one another.

Hoppy,
Will fish out a Deans micro and slap it on the end and repeat and post results after I've had my coffee.

Mark
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Old Nov 13, 2009, 09:18 AM
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Any chance that the meter probes are making poor contact? It might be worth having a section of heavy guage wire to measure as a reference or standard.

Keep up the good work?
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Old Nov 13, 2009, 09:31 AM
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Quote:
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Any chance that the meter probes are making poor contact?
Nope, probe contact resistance is zeroed out as I'm merely measuring voltage and thus no current is flowing through the meter. That said, I did hit the bus wire with 240 grit to remove surface oxides to facilitate solder flow and allow for easy meter readings.

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It might be worth having a section of heavy guage wire to measure as a reference or standard.
12 gauge wire is ~.13mOhm/inch. 14 gauge wire is ~.21mOhms/inch. 16 gauge wire is ~.33mOhm/inch. How I've memorized this is troubling.

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Keep up the good work?
Thanks!

Mark
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Last edited by mrforsyth; Nov 14, 2009 at 02:11 PM. Reason: decimal point correction
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Old Nov 13, 2009, 09:48 AM
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Here you go Hoppy.

Resistance across Deans Micro was 1.52mOhms. Pretty tidy for such a little bugger. One guy I know uses these for everything. Have seen him use them on a 4 cell EDF pulling upwards of 50 amps. Not something I'd do mind you but it sure put a grin on his face.

Photo below of added Deans Micro for anyone who may not trust my integrity.

Mark
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Old Nov 13, 2009, 10:06 AM
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Mark,
Do you have access to an EC3 connector? I'm using them and would like to see where they measure in.
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Old Nov 13, 2009, 10:18 AM
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Mark,
Do you have access to an EC3 connector?
I do have the battery end that I chopped off some HC lipolys but unfortunately do not have the mating end. I would expect them to be in the same ballpark as the above.

Also have some HXT 4mm's that I'll throw in the mix if I can figure out how to extract the contacts from the housing without destroying them. May dig into my bins full of 3.5mm and 4mm gold bullets as well.

Right now I'm going to head out and discharge my 'loads' since I'm taking the day off.

Mark
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Old Nov 13, 2009, 11:34 AM
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Thanks Mark. Nice test.

Boy, you sure do eat large popsicles - are you sure those sticks aren't tongue depressors?

Bill
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