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I want to make a power connection between my PCB and an accumulator. I need it to handle up to 100A, and to be mechanically very strong, because it will be on board of a buggy car model.

In the prototype I made with a Perfboard (dot pcb) I split the big wire into 16 smaller sections, and I pass each of them through a different hole. Then I solder all together in the bottom.

Two big wires split in 16 small portions Can't fit a PCB bus bar

Wires and connectors are standard from model hobby:

That works really well, as it is both strong and accommodates the large wire in quite a small footprint. I've used a similar technique to retrieve output current from the half-bridges underneath the dissipator.

Now I would like to make a printed circuit, and I would like to replicate the same kind of connection, but I'm unsure how to proceed:

  • Creating a component that contains multiple through-holes, too close to each other fires up plenty of design rules error.
  • My PCB editor (Proteus - Ares) believes that each through hole is a different connector, so it is awkward to create a component.
  • I prefer to remain as standard as possible because I order my PCB to a commercial manufacturer.
  • Some comments suggest to use a PCB bus bar. I understand that this would make a great connection, but I don't see how I could possibly fit them in a circuit that goes onboard of a model car. Circuit is a BLDC controller, and has 2 power inputs and 3 power outputs.

I would welcome any idea, including creating the connector in a different way, or using a different PCB editor.

Edit

Chris Stratton suggested to look at an actual commercial ESC module. I should have started by that. Here is the disassembly of one:

550X ESC Disassembly - HeliFreak 550X ESC Disassembly - HeliFreak

Now I have more questions:

  • It looks like the power cables are soldered to a metallic area reinforced with small dots. Someone knows what it is?
  • On the other face there are a kind of slab. Is this a power bus?
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    \$\begingroup\$ You won't convince me that PCB trace has the same cross section as the wire. \$\endgroup\$ – Marko Buršič Sep 4 '16 at 9:19
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    \$\begingroup\$ Directly soldered wires aren't the best for vibration; you want PCB bus bars with terminals: electronics.stackexchange.com/questions/59735/… \$\endgroup\$ – pjc50 Sep 4 '16 at 9:32
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    \$\begingroup\$ The bus bar or the stiffener is definitely a good idea. You can also add some cutouts on the smask and pour solder on them, you can sometimes see that in high current traces. Also consider using multiple layers for the trace. And of course keep the tracks short. Anyway, the problems you are encountering are cad related and should be trivially solved, I have done something similar with KiCad, so any tool can do that. \$\endgroup\$ – Vladimir Cravero Sep 4 '16 at 11:16
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    \$\begingroup\$ I'm using standard cables specifically designed and manufactured for model cars of the same size and power as mine. \$\endgroup\$ – jmgonet Sep 4 '16 at 11:23
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    \$\begingroup\$ Seems like a cool project! I had a quick look and it seems you can solder EC5 and bullet connectors to a PCB, maybe you have some laying around and you can make some does-it-fit tests. I am still quite convinced you need to find room for the bus bars. I tried some quick numbers and I get 6W dissipated on the track, not sure if this is acceptable. \$\endgroup\$ – Vladimir Cravero Sep 4 '16 at 12:28
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From the photos it looks like you are desiging a brushless driver for RC car , the RC car motor and batteries are sized for short pulses of high current and not continuous , so the limit in your case is not the PCB traces .

BUT anyway i will present some of the methods used :

  1. Using a High or VERY high thick copper PCB (4oz to 20oz) probably the most expensive and not available anywhere

  2. Copper bus bars welded or screwed into PCB

  3. Copper wires soldered into PCB

  4. Solder wick/Braid , this is my favorite since it doesnot required the amount of heat that the previous methods used which leads to permenant PCB bend.

very compact High current ESC

bus bar pcb stiffeners

copper bars

Wire

screwed bus bar

MY Preferred Solution :

solder braid

EDIT: Added PCB termination

Wurth Electronics power elements

wurth power elements

or lugsdirect PCB Wire Connectors

lugsdirect

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  • \$\begingroup\$ JOOI, if you soldered those copper bus-bars, did you pre-heat them in an oven or such? \$\endgroup\$ – Andrew Morton Sep 5 '16 at 18:32
  • \$\begingroup\$ i personally donot know how the correct process \$\endgroup\$ – ElectronS Sep 6 '16 at 7:48
  • \$\begingroup\$ Thanks for this practical answer about layers. I've used a braid in my current Perfboard, and I can confirm that it is both easy to implement and doesn't bend (too much) the circuit. However, my original question was about how to connect the power cables to the PCB. I've seen in one of your photos that you use a bolt and screw plus a cable lug. Could you give me some insight? \$\endgroup\$ – jmgonet Sep 6 '16 at 13:26
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    \$\begingroup\$ @jmgonet , make a big pad lets say for m6 screw the pad should be (hole:6-6.5mm and outer ring about 12-14mm) then use a brass screw and a nut to lock the screw , if you can use solder on both to lock them in place. then you put the wire lug and tighten it with a second nut. there are some ready products that i will add in my answer that also solve this problem \$\endgroup\$ – ElectronS Sep 7 '16 at 9:11
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It looks like the power cables are soldered to a metallic area reinforced with small dots. Someone knows what it is?

It looks like those are vias-in-pad. My guess is that they are stitching the top metal layer all the way through to the bottom for both good electrical conductivity and structural integrity. I would suggest to use all metal layers in the pad.

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