Electric vehicle with a replacement battery pack
Pre-charge fault on a battery pack the shop swore was new
By Sebastian Rivera
The short answer
The fault was in the pre-charge circuit of a battery pack the shop believed was new. It turned out to be a used pack of unknown condition, and when the supplier opened it, the pre-charge resistor had exploded.
- Down
- 6 weeks
- Found
- under 3 hrs
- Already lost
- $100K+ in penalties, at $2,500 a day
- Vehicle
- Electric vehicle with a replacement battery pack
- Symptom
- Pre-charge fault after a pack replacement
- Already tried
- The shop had just replaced the battery pack and was sure it was new.
How it was found
- Followed the data instead of the assumption that a new pack ruled the pack out.
- The data pointed at the pre-charge circuit inside the pack.
- The pack turned out to be used, of unknown condition.
- When the supplier opened it, the pre-charge resistor had exploded.
Root cause
A failed pre-charge resistor inside a used battery pack sold as new.
What this means for your team
A part being new does not rule it out. Let the data decide where to look, then verify the part, especially when its history is unknown.