An easy quip for haters is “you’ll have to replace the battery,” at a significant cost. Lie- No, I won’t.
I’ll just say it: Zero claims a battery life of 3,000 charge cycles before falling to 80% capacity. Depending on pack size ordered and city vs. highway use, this would mean 120,000 to 300,000 miles– essentially, the life of the vehicle. The number of people who will ride a motorcycle over 120,000 miles is low; the number over 200,000 might as well be ignored. This tracks well with Toyota and Ford numbers and experience, which I’ll get into.
Starting with the Toyota hybrid in 1998, large automotive packs have gathered plenty of experience. This includes taxis, which includes desert and Canadian taxis. Mass failure of taxis and batteries has not occurred; one Canadian cab is still going after 400,000 kilometers. Notice I said “mass failure.” Even when lifetimes are “reached,” it has been found that only a few bad cells in the pack need replacing, at marginal not system cost. And that’s to the arbitrary 80% capacity; a hybrid can run fine with a 70% battery pack. But even this is assuming you’d take the bill; battery packs are required to be warrantied to eight years/100,000 miles in most states, and 10 years/150,000 mi in California-compliant states. In other words, don’t worry about it. The manufacturers don’t even like having separate state-by-state inventory, so all vehicles effectively get the 10/150,000 pack design (“homologation”).
Now, most of this experience is with Nickel-Metal Hydride (NiMH) cell chemistries. Lithium chemistries have only been sold for highway use for a few years, though of course both smaller devices and spacecraft have been using them longer. According to Ford, lithium will actually beat NiMH. So far, lab and field tests have lithiums tracking above NiMHs in lifetime capacity and longevity. This jibes with Zero’s claim.
The obvious exception, of course, is the Nissan Leaf issue. A fraction of owners in Arizona and inland California reported fast degradation and decreased capacity, and got compensation. In this case, Nissan cheaped out, and used an air-cooling system for the Leaf battery pack. Chevy, Ford, etc. are offering liquid cooling for their EVs, and have not seen this problem. When under high current, a battery generates heat; if it’s already hot out, the pack can exceed its design limit. All vendors anticipated this, but Nissan thought it could get away with just fans. This didn’t pan out where the air temperature itself can be over the design limit. Note that Leaf owners in temperate regions have not had this issue.
In the case of my motorcycle, the pack size is so small and exposed, no real heat buildup occurs. At 6 kWh, it’s a fraction of the size of the Leaf or Volt. In particular, no ‘innards’ are buried deep enough, in the pack or in the vehicle overall, to retain high temperatures. Other Zero owners have measured their pack temperatures after hard riding on hot days, and found nothing of concern. Even this is assuming the vehicle computer and its temperature sensors fail to protect the pack. The manual warns that the computer will dial you back, and eventually shut you down, for thermal excursion. But I’ve only heard of one or two owners who have seen this; it’s never happened to me at all.
I anticipate that my battery will be economically obsolete (rendered so by some other cell) before it becomes functionally degraded. That is, I don’t worry about it.