I’m trying to design a PCB to enhance the power distribution in my boat. What I’m trying to achieve is a board getting 12V 100A in and distribute it to 6 outputs protected by fuses so each output will be up to 30A. Most outputs will be less than 10A so the thought is sound I think…
Each module of outputs should have a uC that will communicate with a bigger uC at the helm where fuse status and possible power consumption is shown.
An additional idea to save copper wires is to let the outputs be relay controlled where each output can be controlled by a much thinner copper wire to the cockpit button. I have trouble finding relays for PCB that can handle the current tho.
My question is really… Is this feasable, and can anyone help me with the calculations for the trace width? And ideas on how to make the trace width smaller by for example running wires along the copper trace is also cool.
Suggestions on relays I could use for this is also welcomed. Parts should be stocked at Mouser or Digikey, or I’ll get trouble getting them.
Valid question. Using a PCB uses less space and it opens for a world of additional features like broken-fuse detection, current monitoring and much more. It will also be cheaper and easier to assemble.
The question is mainly for the high current and I didn’t emphasis the additional stuff as it’s all depending on if the high current is possible/feasable.
100A is very high for a PCB. You can get the copper plated to 4oz (the usual is 1oz), but you would probably still want to beef-up the tracks. I suggest you leave the high current tracks without soldermask and then solder some heavy copper braid (e.g. thick solder wick) along the tracks. An alternative is soldering copper strips to the PCB. I cut out some “K&S” brand copper sheet from a hobby store, and used solder paste to bond it to the PCB. Since I had a bunch of surface mount parts on the same PCB, it was all soldered in one operation (oven or skillet should work for this)
As for relays, I’m sure you can get relays at least this rating, but if I was trying to control this type of load I’d probably look at MOSFETs. These days you can get really high current devices & they’ll be a lot more compact than relays.