Never mind top/bot. balancing, or BMS/no-BMS. What really kills your pack is...

I've attempted to quantify the percentage of damage to Li-ion traction packs according to cause and level of damage.

The result that might be most interesting to this group is that the hotly debated technical issues (where to balance, BMS or no BMS) play only a minor role in the distribution of the causes of Li0ion traction pack damage.

In reality, most causes of damage to Li-ion traction packs are the old fashioned ones: short circuits, AC power wiring, limited-education, unwillingness to follow directions, and plain old making stupid mistakes.

I found it helpful to subdivide the damage into 3 categories: damage to a cell, damage to the entire pack, and fire, because each is affected principally by a different set of causes.

All levels of damage:


Cell damage only:


Pack damage only:


Fire only:


Caveat: these data were collected over the period of a few years from actual experiences reported to us privately, anecdotal evidence and reports in the media and social media; they lack scientific rigor. Therefore, I apologize for errors and I do welcome your input.