Gen2/Calex Charger/Damage Report

From Unofficial Zero Manual
< Gen2‎ | Calex Charger
Revision as of 21:19, 12 January 2020 by BrianTRice (talk | contribs) (BrianTRice moved page Calex Charger Teardown to Gen2/Calex Charger/Damage Report)

(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)
Jump to: navigation, search

This showcases a teardown and de-potting of a Calex 1200 charger from a 2016 DSR model, following a total failure of the charger.

Board topside completely uncovered
Board underside mostly uncovered
Odometer estimate when the charger failed: 31000 miles.
Symptoms observed prior to the fault:
  • Excessive sparking at the inlet despite cleaning and using a hospital-grade cord.
  • Prior failure at 30,000 miles of the Sevcon DC-DC converter.
General Observations
  • A component on the board overheated and caught fire.
  • The fire burned through the board.
  • The rubbery potting extinguished and contained the fire.
Design Observations
  • The board is mounted on the upper side of the charger casing, with the largest/heaviest components suspended below it within a great mass of potting.
    The board itself is mounted very close to the surface that is flush with the underside of the main powerpack casing on the S platform.
  • The rubbery potting fills the case volumetrically, and is likely poured in as a substance which then sets chemically or thermally.
  • The board surface is nearly as large as the enclosure, and seems too thin for its span to support the mounted components on its own.
    The components seem mainly supported by the potting.
    The board's unusual size could be an attempt to increase the distance between components.
    This might be intended to reduce the intensity of heat buildup inside the charger, after the 2014-2015 design proved to be prone to failure.
  • The board's capacitor banks do not seem adequately shielded from current inrush.
    This lack of shielding probably plays interacts with a dirty charging inlet and possibly also interacts with a glitchy DC-DC converter on the main/output bus.

The photos presented are all oriented with the rear/connection side of the charger pointing to the right.