Electronics Assistance With DIY Drone (100 Amp Draw?)

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Hello everyone,

Apologies in advance—this is my first time building a drone, and it’s for a university project. I’m mainly a computer science student with only basic knowledge of electronics, so I’m not entirely confident my wiring diagram is correct. I’m also running into trouble connecting all my parts together.

CircuitDiagram
CircuitDiagram1224×711 15.9 KB

I’m building an underwater drone for 3D modeling underwater structures, loosely based on the BlueROV design (sorry Blue Robotics, can’t afford one :sweat_smile:). I’m using some BlueROV parts, like their housing (15.6 aluminum locking tube) and cable glands. There is only one housing for everything, including the batteries. For power, I’m working with a Zeee 10,000 mAh 4S LiPo (not the exact one shown in the diagram).

I calculated the estimated power draw to be around 100 amps, and now I’m worried that the 8 AWG battery wire won’t handle it safely. Here’s my rough estimate:

  • 13A per motor × 6 = 78A
  • 5A per Raspberry Pi × 2 = 10A
  • Unknown servo current
  • Lights = maybe 3–4A, though I left headroom up to 10A

So potentially around 93–98 amps total. The motor ESCs are 50 amp if that helps as well. Can someone confirm if I’m on the right track here?

My assumption is that I’d need thicker wire, maybe 4 AWG or even 2 AWG, but I’m not sure. The wiring diagram I shared is more of a garage test setup so I had something to build off of. I’m now unsure what power module to use, especially since 100A seems to rule out most standard ones.

Also, I’m using a Pixhawk clone (couldn’t get the original), and I’m not sure if that affects which power module or power distribution board (PDB) I should go with.

If anyone has advice or suggestions, I’d really appreciate it. Sorry again if this all sounds very amateur and sloppy, I’m trying to figure this all out as I go without shocking myself or setting fire to my garage haha :sweat_smile:

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Hi @Arcusmaster1
Welcome to the forums!
Your diagram looks sound, but all those fuses are likely unecessary and using up a lot of space and $$! You’ll notice that the BlueROV2 does not fuse the ESCs or power supplies… in general, surge currents can be quite high and make the fuses trip as a nuisance!

Many users have hoped to save money by building their own vehicle - generally you may find the economies of scale leveraged by BlueRobotics does make that the cheaper option, in the long run, but this will depend on your own fabrication costs.

As for your current estimates - you’re seemingly calculating a worst case load! A Raspberry Pi is not capable of drawing 5 amps - at most it draws 5-8 watts, when under load. The motors may be able to draw more than 13A, but when driving around at 50% gain, are unlikely to all be running at once. Forum posts in the past have discussed this… @EliotBR may be able to point you to these discussions as I couldn’t find them with a quick search.

As long as the pinout of your Pixhawk matches the pinout of the PDB, you should be able to connect and configure it to measure voltage and current appropriately! I hope you plan to run BlueOS on your pi with the connected autopilot…

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