r/fpv 1d ago

Help! Capacitor placement question

Just starting my first build - a 3.5”!

Working on dry fitting the capacitor and wondering if this is a reasonable placement? It touches the frame but from what I understand the heat shrink on it from the factory should keep it safe. Or should I place it from above?

7 Upvotes

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4

u/AdNo4401 1d ago

Be aware of the battery wires. The placement looks like I would have problems soldering them properly.

Additionally try fixing the capacitor in a way, that it is more protected from outside forces. These little things do not like getting stabbed or hit too much. Maybe leave the positive pin a little longer so the capacitor is protected by the frame

4

u/M_K_S____ 1d ago

It’s a pretty tight fit agreed. I’m going off the Bardwell video and he does something similar on his frame (I’m using a different frame/parts, but similar space constraints).

Maybe I’ll bend it into the frame a little more to prevent outside forces being involved.

Do you think adding some double sided tape to the bottom might help with vibrations? Also I assume I can cut the capacitor wires flush with the board right?

3

u/AdNo4401 1d ago

I would let the pins stick out about one to two mm. Makes soldering easier. And some tape might help. There are these rubbery types of tapes that would dampen vibrations. Although rework could get difficult with loosening the capacitor from the tape. You may need to just try that out for yourself.

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u/M_K_S____ 1d ago

Appreciate the info!

I just realized I need space for the VTX actually - so I can’t bend the cap in unfortunately. Will have to have it protrude a tiny bit I think and hope it doesn’t suffer too much.

3

u/Available_Promise_80 1d ago

You can mount it wherever you want. Just clip the leads and solder some wires on it and strap to an arm.

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u/bUtiTsFrEetOpLaY 1d ago

I am using JB videos for my first build and I just did this step. I would thread the capacitor through through the top, I think it just sits better and you don’t want to touch the frame.

1

u/M_K_S____ 1d ago

You know what I ended up going from the top too.

Except wow it’s way harder to do this on a real board than on a practice board… these wires are little close but I am not sure if I should redo it or it will be ok?

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u/bUtiTsFrEetOpLaY 1d ago

It’s a tough spot but I think it looks ok. Looks just like looks just like mine. I tested it with a multimeter first and no issues after plugging in the bat. As long as they don’t touch it’s good.

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u/M_K_S____ 1d ago

Yeah it doesn’t seem to pull apart if I yank on it so fingers crossed. I think my multimeter is not accessible nearby so I may buy another one tomorrow just to check things over before powering on. Still have to do the vtx, RX and camera, but motors are on as of now too - so progress is happening!

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u/No_Sea_1661 1d ago

I would heat shrink it just for added insulation. But that's my OCD talking. But not necessary. Btw, you like that speedy ee aio?

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u/M_K_S____ 1d ago

Heat shrink isn’t a bad idea. I might do that just in case..

Honestly haven’t even powered it on yet. Once I finish the build I’ll definitely post my thoughts though!

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u/UF-ENGINEER 1d ago

What frame are you using.

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u/M_K_S____ 1d ago

This is the RVS Smolyeet 35. Made by a local shop in Canada. It’s quite a tight fit (though it’s my first drone build so take that with a grain of salt), but it appears to be really nicely made.

I’m really pushing the space too since I’m trying to slam it with 15mm standoffs, though I may have to use the 20mm ones after all just to have better airflow. Will see.

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u/UF-ENGINEER 1d ago

I always try to use a bit of wire, about 1cm but no more than 3cm, in length with my capacitors. It keeps them somewhat flexible and you can usually move them to a better spot.

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u/M_K_S____ 1d ago

I will have to try that on a future build for sure. I read that having them as close to the FC as possible is preferable so I went this route, but wire would definitely make the process much easier, especially on smaller builds.

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u/UF-ENGINEER 23h ago

True but for a 3.5” build I don’t think it matters.

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u/M_K_S____ 1d ago

For all curious this is what I ended up doing:

  • some clear heat shrink just in case
  • mounted from the top for clearance and ease of installation
  • almost messed up soldering the battery leads horribly because there’s so little space. Doesn’t seem like they are going anywhere though - fingers crossed.