Dead Charger Repair, How To (Summary and Discussion)

[kiev]

The onboard chargger OBC troubleshooting thread has technical circuit board details, but this thread is intended to be a simple HOW TO for fixing the OBC.

The technical investigation is still in progress, but circuit details are not of much practical use for most folks.

So far it seems that only a few components have blown in failed OBCs, and skylogger has successfully repaired 2 units by replacing these parts.

What typically Blows or Fails?

#1. The 20A fuse in the MCU.

#2. The high voltage snubber capacitors.

#3. The ceramic pre-charge resistors on the Neutral line.

#4. The AC input relay on the Neutral line.


Why are these failing? We don't know exactly, but it appears that:

F1. Anything that could suddenly interrupt normal charging (e.g. pulling the plug, mains power outage, etc) will cause large voltage spikes in parts of the circuit to blow #1 and 2 above.

F2. Any disruption of the internal low voltage supplies (weak or old Aux battery, bad relays in fuse box, etc), or frosted contacts in the AC input relay, will blow #3 and 4 above. In addition this could cascade to cause a sudden interruption while charging, i.e. F1 above.


Parts:

If there is sufficient interest, then i would consider a bulk order of these parts to put together a little repair kit.

 

[kiev]

Reserved for Index

 

[kiev]

i heard of a fellow (not on the forum) who was getting a replacement OBC from a dealer at a greatly reduced cost, ~$500.

Maybe the recent numerous failures of the OBC has risen up to Mits to where they are realizing a problem and dropping the price as a goodwill gesture? It may be worth asking your local dealer to inquire about an adjusted price for a replacement OBC.

 

[JoeS]

kiev, thank you and skylogger and electronpusher and coulomb and jray3 and Quixotix and all the rest for the wonderful collaborative reverse-engineering investigations. Really appreciated!

As far as the causes, especially power interruption - I think I may be in trouble, as for the last six years almost all of my charging of three i-MiEVs has been done using a mechanical timer, sometime two or three times a day on each car. We've become quite adept at simply keeping the charge levels between four and twelve bars and don't hesitate to let the cars sip, even for a short while.
http://myimiev.com/forum/viewtopic.php?f=7&t=129&p=2910#p2910

In addition to wearing out the shift lever (by constantly jumping into Neutral), my i-MiEVs should be the first to go if power turn-off glitches are a primary culprit.

The only thing I've done so far to address the charger/dc-dc issue is place some fans under the back of the car pointing upwards.

 

[Gorfllub]

I called my local Mits dealer here in Canada. Charger is still ~$4300cad.

If the reduced cost charger is available in the US, I would probably buy one. Then if mine blows, I can install the new one and repair the old on a relaxed schedule without any real loss of use of the vehicle.