Jump to content

MOSFET capacitor exploded - reasons?


Recommended Posts

Hey folks!

I just burned the second MOSFET of my Z10. But that time - look:

photo-2020-11-26-18-53-20.jpg

All three capacitors (that is what I think they are) exploded. It happened just during a drive, no acceleration, only rolling out, at the 5th km of this trip. The last 2h before the drive the wheel laid in the cold (1°C / 34 °F).

Any idea why that could happen?

Link to post
Share on other sites
15 hours ago, Boris Lämpel said:

Any idea why that could happen?

Capacitors seem to be one of the weak spots beside mosfets...

They could be massively overburdened if my assumptions are somewhat correct https://forum.electricunicycle.org/topic/18815-capacitors-on-motherboardsany-tech-gurus/

In some wheels capacitors and mosfets are placed very near together - so both are (over)heating each other...

In this forum are many/some pictures from fried GW man mainboards with capacitor and some mosfets gone...

Here a recent report of a ks capacitor blown https://forum.electricunicycle.org/topic/20224-recovering-after-an-s18-crash-would-love-some-thoughts/

 

 

Link to post
Share on other sites
6 hours ago, Chriull said:

They could be massively overburdened if my assumptions are somewhat correct https://forum.electricunicycle.org/topic/18815-capacitors-on-motherboardsany-tech-gurus/

Thx! I had not read that topic before.

So there could be 2 reasons:

  • I had a big crash (40 kph) ≈50 km ago. But I can hardly imagine that this is the reason for affecting the mother- or powerboard in a destroying way. In the Z10 it is protected very good.
  • Changing high current is always a strain for capacitors. I love hard accelerating and braking. Additionally there was a long and steep hill I climbed a short time before.
    The MOSFET was about 200 km old. Maybe I drove it too aggressively for the last 200km...

Do You know, whether the cold can affect the durability of capacitors? Maybe they also got too hot too fast so that the material could not bear it.

Link to post
Share on other sites
2 hours ago, Boris Lämpel said:

Do You know, whether the cold can affect the durability of capacitors?

If it"s not freezing it should not affect capacitors. Although i have no idea if temperatures below zero affect this capacitors in any way.

2 hours ago, Boris Lämpel said:

Maybe they also got too hot too fast so that the material could not bear it.

No. It's not the temperature change gradient killing this capacitors - it is absolute temperature.

Link to post
Share on other sites
  • 3 weeks later...

If you look right above the bottom left screw the ic marked U15 is severely damaged, likely a voltage controller or other regulating iC that can be repaired with some patience, new caps, and new Ic, provided there isn't many other fried parts along the chain.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...