kiev wrote:If the fuse blows during operation of the OBC, then it is very likely that the two snubber capacitors in the HV output section will also be destroyed. This scenario has been reported dozens of times in the past 2 years in the OBC Troubleshooting and Repair thread.
So looking at this another way-- could the fuse have a limited lifetime due to age, wear and tear, etc?
This theory makes a lot of sense. By my calculations, the fuse has approximately 9 amps flowing through it for up to 5 hours at a time during a level 2 charge. While it may not warm to any significant degree, it is a heat load that can fatigue the fuse. Also, the car is usually driven after being charged, so now a warm fuse is getting jostled by driving. Plus, as the fuse ages and develops weak spots, this causes more heat buildup, further degrading the fuse until it eventually breaks, usually under the thermal strain of charging. The DC-DC converter can pull 3 amps at most, usually less than an amp during normal operation, so even a fuse on the verge of blowing could keep power flowing without too much trouble while driving, which means we see most failures during a charge.
When this fuse goes, the full charging current is interrupted, which could likely be causing a voltage spike on the charger side and blowing the capacitors by over-voltage.
kiev wrote:...driving on our typically smooth and pothole-free highways...
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