Suggestions for battery warranty

Nissan has said that there are many things that I as a driver can do to maximize battery life:

• 
  Don't live in Phoenix
  Don't use a Level 3 charger
  Don't drive with a heavy foot
  and more

All the suggested warranty options are one size fits all. As a result A hot-rod driver in Phoenix with a Level 3 charger at home gets the same warranty as I do and I'm a smooth driver in a mild climate with a Level 2 charger. Which means either I get less warranty than I should or I pay for the warranty for the hot rodder. Given the level of computer power in the Leaf there is an alternative.

I suggest that the battery warranty be a simple, public function of readily verified data. The Leaf can monitor and record the environmental heat load, the charger use, the load statistics and based on those values compute a warranty curve. If battery capacity drops below the curve, the warranty kicks in.

The function must be public and users must be able to access the data the Leaf records. Further it would be best if the inputs to the formula were easily understood and could be estimated with reasonable accuracy independent of the Leaf. Each of the inputs to the formula should be discrete, eg 5 for Phoenix-like climate down to 1 for SF-like climate, 5 for daily use of Level 3 charger down to 1 for zero use of Level 3 charger, etc. A purchaser could estimate their values for the warranty formula and see what curve they would likely get. Over the life of the vehicle they could compare their estimates to what the Leaf itself was recording and possibly adapt their behavior.

This would have to be very transparent and very easily understood to work. But it would provide careful drivers with a warranty that truly covered battery failures without excessive cost due to drivers that stress their batteries.

Your logic is valid and reasonable.

Well - too many variables they don't control. People move from place to place etc.

More importantly, people want worry-free warranty. Not something based on things they don't control - like weather.

I expect there should be certain limits for crossing critical thresholds. I.e., you could only invade the reserve capacity x number of times, only a certain number of sustained/continued driving into over-temperature warnings, etc.. Only a limited number of "get out of jail free" cards, beyond which there would be consequences for the warranty. As long as these events are reasonably easily avoided, and come with plenty of advance warning, it would seem like a fair way to limit abuse. Or, perhaps the car will limit the driver so that significant hits to battery life aren't possible?

I expect that the LEAF will (at least should) limit use to avoid self-"destruction" by abusive or overly-agressive use.

The warranty is likely to contain verbage that tampering, use outside "operating limits", accident, riot, flooding, fire, etc., or abusive use will void the warranty.

Sorry I guess I always drag threads OT but wouldn't a big capacitor help with fast acceleration by smoothing out the big spike in current draw from the battery?

The significant word would be "big".

Something's been nagging me about the warranty and our desire to guess what the warranty might tell us about battery performance. It hit me last night - warranty is marketing not tech.

Lithium manganese cells have been around since about 1996. Nissan started working with lithium ion cells more than 16 years ago. When a company works thru the product cycle with the intention of bringing something to market they don't gamble - they're in business to make a profit and gambling just isn't part of the process. I suspect Nissan knows exactly how their battery will perform in a number of climates and driving styles and I'll bet they've got spreadsheets filled with all the risk parameters.

A lot of marketing seems counter-intuitive (at least to me!) A company will run a number of advertisements that are generally the same but with color differences, or with a couple of minor wording variations, to see which results in more sales. One of the variables that's tested is price; another is warranty. Some people shop price, others see a higher price and assume higher quality or higher status. Some are comforted by a longer warranty, while others wonder what's wrong with the product if the warranty is longer than similar items on the market. A marketer will run all the tests to see which combination of factors sells best. A company cannot focus on any specific person or group. It's not in any company's best interest to change a parameter to gain 200 sales from one sub-group if that same change kills 2000 sales from other potential customers.

It'll be interesting to look back once we've had our Leaf for a year or two and see how the marketing choices settled out

Maybe they can make the warranty vary depending on amount of miles spent in each mode. For example, in regular mode 80,000 miles, in Eco mode, 120,000... and vary the warranty length depending on how many miles are in each mode (50/50 in each mode would be 100,000 miles). Eco mode puts less stress on the battery (as well as other systems), so it would last longer. Presumably, the car has the ability to record the information needed and give the user a readout.

Doing the warranty by driving style would be hard, but by mode would be easier.