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Thread: Power rails

  1. #1
    Max's Avatar
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    Max Medhursr
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    Hi all,
    I was wondering if anyone had any good systems for featherweight power rails? With drive escs, weapon esc, the battery and power light all needing to be connected in parallel a set of power rails seems like a good idea, I'm just not sure what to use.

    I had thought about using something like a screw earth terminal block (http://uk.rs-online.com/web/p/earth-blocks/0425544/) but not convinced the wires wouldn't work loose

  2. #2
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    Wire loom with all connections that don't need regular disconnections soldered. The rest with good connectors.

    And no, Anderson connectors ain't that good.

    Those uninsulated screw connectors you show are just asking for trouble.

  3. #3
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    Like Mario said, that terminal block is going to cause problems - expensive, smoky problems. The most reliable connectors for a power bus style wiring loom are crimped ring terminals (as long as you use a high quality crimper) and insulated binding posts. You need to cover the posts with tape after everything is assembled but they will never fail in normal use.

    I now prefer point to point wiring using XT connectors; I'll have a larger XT90 for the battery connector and XT60 connectors for the individual motors. The wiring gets lighter as it fans out - 8 or 10 gauge at the battery, 10 or 12 gauge for the weapon motor and 14 gauge for the drive motors. That scheme makes for a light and compact wiring loom that is reliable and takes plenty of current where its needed.

  4. #4
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    I've moved from connector blocks (they were 4 way blocks that accepted ring terminals, got them off ebay) to pretty much what Nick said. [except for a Brit using metric cable ]

  5. #5
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    I've just been using EC3s for the most part, with 10 and 12 AWG wire. Just bought a 100W soldering iron and gobbed them together, then wrapped the joints up in tape. 10AWG won't fit nicely in the EC3s though - what connectors do people usually use for that (and larger)?

  6. #6
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    Team RCC used EC5 for main connections, EC3 for motors (up to Bosch 750) and EC2 for solenoids, LED's and other low power applications.
    But we're transitioning to XT60 and 90, as HK delivers most of their stuff with those presoldered on.

  7. #7
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    XT90 connectors work well up to 10AWG wire. They have a 'no spark' version that is ideal for battery connections.

  8. #8
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    Just another question about fuses - the rules say you need to have a fuse rated below your battery's maximum discharge current. For me, I have a battery which lists 65C as its continuous discharge, and 130C as its burst discharge rating. As far as I know, that means the max burst discharge current is 130*3.3Ah (or 3300 mAh) = 429A is my max burst discharge. So I bought a 400A fuse, but now it's here, it looks enormous. Am I going crazy, or is this what people normally use?
    0-376-40-Purple-Mega-Fuse-400A.jpg

  9. #9
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    The 400A fuse is according the rules.

    Team RCC didn't use a 400A fuse in any of our machines.
    The "heaviest" was a 200A car-audio fuse in our spinners Caliope and Valkirie.

    Currently, Hannibalito is using a 30A fuse (on the IBF ESC) and Kashei a 100A.(this is part of the link)

    A few questions.

    What are you powering?
    How thick are the wires in the machine? (Battery leads to start with)
    Last edited by maddox10; 30th March 2017 at 15:36.

  10. #10
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    I have four 18V drill motors and a brushless RC car motor all powered by three TZ85s, so it's clearly drawing nothing like 400A. I just thought going for the max fuse size I could would be the best, since I can always reuse it anyway. Battery leads are 10AWG, as are the leads going to the removable link and fuse. 12AWG wires branch out from those to the three ESCs, which also use 12AWG wire for output to the motors.

    Should I use a much smaller fuse? I have no real way to measure the current drawn - my multimeter only goes up to 10A.
    This is the brushless I'm using - it powers my linear actuator: http://www.componentshop.co.uk/lbh36...or-2-pole.html
    Last edited by R9000; 30th March 2017 at 16:50.

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