Valdemar wrote:Leaf has oversized brakes for the size of car it is and even larger cars. Sure it is heavier than other cars of the same size, but the overheating concern while not unfounded is likely not much to be worried about unless we are talking about race track like driving down the mountain.
While Nissan is to be commended for giving the LEAF larger brakes, I would have to disagree about brake overheating. It is a very real concern for anyone descending a big mountain in a LEAF with a degraded battery. As our LEAF technician demonstrated, loss of regen on a nine bar LEAF is less of a problem if descending on a very low charge (at around "low battery" warning or below) and a warmer battery. But if I want to descend our mountain at 50-60% SOC and four temperature bars, the brakes do overheat and start to shudder. That's true even if I drive well below the speed limit (I've tried virtually everything).
There are multiple problems with having to descend the mountain at a very low SOC:
1. Occasionally, there are emergency road closures (due to rockslides, fires, or serious accidents) that necessitate turning around. I always prefer to leave enough charge to be able to make it back home, or off the mountain via an alternate route.
2. We wouldn't be left with much charge to drive around after completing the descent.
3. We don't normally leave the car sitting at low SOC (see 1, above); it gets charged most nights and/or early mornings. When our LEAF was newer, I usually charged it to 60-70% or so, in order to strike a good balance between available regen, efficiency, and range. That doesn't work now!
Valdemar wrote:After all even when the car was new leaving home on a full charge was a guarantee not to get any regen all the way down.
Yes, but anyone with a basic understanding of EVs shouldn't be surprised by that.
Note that I'm not asking for the 2011 LEAF to be an ideal mountain car, as it never was. I do, however, think it's unreasonable to have such poor regen. I'd be more satisfied if, in regenerative braking, Nissan allowed the same amount of power as when using a DC Fast Charger.
By the way, even at close to 90% charge, our 2012 Tesla Model S usually allows about 30 kW of regen when descending. That's probably commensurate with what a Supercharger would provide at that SOC. On most days that we need to leave the mountain, I charge the Model S to 75% and it gets up to about 81% at the base of the mountain.
Honestly, with respect to our LEAF, I'd probably be fine writing this off as an experiment with mixed results, but it seems that Nissan is continuing to sell cars with battery packs that degrade rapidly and leave their owners with very poor regen.