Author Topic: Why are these connectors so unreliable?  (Read 3925 times)

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Offline TwoTired

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Re: Why are these connectors so unreliable?
« Reply #25 on: March 09, 2019, 11:41:03 AM »
Essentially (speaking here as a lifelong Electronics Engineer/Designer/Programmer), the Molex connectors are an assembly device, and are intended for that purpose. They are intended for building a subassembly of some kind (like a circuit board, or maybe a chassis) at one location and another part of it at another, then they are plugged together in a 'final assembly' and the [completed] system tested. This also provides a semi-modular design for the vendor, in case some portion of it may need to be replaced occasionally (and rarely) at some point. They are not intended for regular (as in, frequent) connect-disconnect cycles, but are often used because they are the cheapest connectors available.

Many designers today don't seem to know this.... :(

Molex, among other brands can offer connector pins made of different materials, plating, and plating thickness for repeated cycles and durability.  Of course, such pins cost more than cheapest available.   The engineer should pick the part for the application and use.  I think you are correct that the base materials offer a 5 mating cycle life.  But, you can get pins with far more mating cycle duration if you shop, specify and pay for better quality, even if it is within brand.

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Offline HondaMan

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Re: Why are these connectors so unreliable?
« Reply #26 on: March 10, 2019, 06:57:50 PM »
Essentially (speaking here as a lifelong Electronics Engineer/Designer/Programmer), the Molex connectors are an assembly device, and are intended for that purpose. They are intended for building a subassembly of some kind (like a circuit board, or maybe a chassis) at one location and another part of it at another, then they are plugged together in a 'final assembly' and the [completed] system tested. This also provides a semi-modular design for the vendor, in case some portion of it may need to be replaced occasionally (and rarely) at some point. They are not intended for regular (as in, frequent) connect-disconnect cycles, but are often used because they are the cheapest connectors available.

Many designers today don't seem to know this.... :(

Molex, among other brands can offer connector pins made of different materials, plating, and plating thickness for repeated cycles and durability.  Of course, such pins cost more than cheapest available.   The engineer should pick the part for the application and use.  I think you are correct that the base materials offer a 5 mating cycle life.  But, you can get pins with far more mating cycle duration if you shop, specify and pay for better quality, even if it is within brand.

Cheers,

Right you are!
But, trying to get the [sales] [factory] representative to help you get those partnumbers from Molex is like pulling teeth...without whiskey... :(
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Offline Deltarider

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Re: Why are these connectors so unreliable?
« Reply #27 on: March 11, 2019, 03:16:15 AM »
In the pic below the extra connector cord that came with the battery charger to facilitate charging without having to remove a side panel. I thought it could be handy and I even added a fuse. After some five connect/disconnect cycles it already was unreliable. I removed it and connected the charger to the supplied longer cables again, the ones with the clamps. No big deal. But as I still use the same connector, the problem followed, so every now and then the cord connectors have to be tweaked. After what I've read here, I'm even more determined to replace them by another type. No more of the same, not even a better quality. I'm done with them.
Whenever you buy equipment, have a look at what connectors are on it and inspect the suppleness of the wires. The wires on mine are the cheap kind and stiff. As a matter of fact, the only supple wires on my bike are the silicone leads to the sparkplugcaps. Although you find these inferior connectors and wires usually on products of Chinese or Taiwanese origin, you can't say they're on all. I have a 30 year old automotive DMM, which has been used a lot, but still has the original silicone wires. Another thing to look at, is the casing. Is it hard plastic that will split on even the lightest impact or is it made of a more forgiving material?
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Offline rotortiller

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Re: Why are these connectors so unreliable?
« Reply #28 on: March 11, 2019, 04:37:06 AM »
Grab these, it has a non-Asian flag on it so it has to be the best. LOL  https://www.ebay.com/itm/132965625543

Offline bryanj

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Re: Why are these connectors so unreliable?
« Reply #29 on: March 11, 2019, 05:05:58 AM »
Cars and trucks use those and they are just as unteliable after multiple disconects
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Offline rotortiller

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Re: Why are these connectors so unreliable?
« Reply #30 on: March 11, 2019, 08:24:44 AM »
How is that even possible, it has a proud mark of excellence? LOL Here's the answer-



Quote
Cars and trucks use those and they are just as unreliable after multiple disconnects
« Last Edit: March 11, 2019, 08:27:42 AM by rotortiller »

Offline BigJimG

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Re: Why are these connectors so unreliable?
« Reply #31 on: March 11, 2019, 04:05:49 PM »
Back when I used to race R/C, I liked these connectors.  The only issues I ever had with them is they DO NOT like the electric motor cleaning spray we used to clean the motors.  The plastic would crumble.

https://powerwerx.com/anderson-powerpole-connectors-30amp-unassembled

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