Fast-charging capacitor in 2014 Mazda 6

[Occasionally6]

Originally Posted by RedDevil

If I read correctly, it is only used to power the electric systems during idle stop. So those don't drain the battery, so that can be kept small.
I fear the system will cost a hell of a lot more though than that heavier battery.

It is no use for a hybrid because they already have that heavier battery to store brake energy to not only power the equipment during idle stop, but also to help accelerate when the stop ends.

Supercapacitors have a very limited capacity compared to batteries.
In the article Mazda claims the capacitor can store 25,000 Joules. The Insight might use up that capacity in 2 or 3 seconds during acceleration.
For effective hybrid use it needs to have at least 5 times the capacity, which I fear will make it too heavy to be practical.

I'd love the properties of a supercapacitor big enough for hybrid use, except the weight.

It's only being use as an energy storage buffer isn't it? The alternator is capable of generating (capturing) electrical power during braking at a faster rate than a typical automotive battery can accept charge at.

While the captured energy might be used during an idle off condition, it could also be used instead of driving the alternator off the engine, at least part of the time.

The capacitor can take the rapid charge that the conventional battery cannot and bleed it back into the battery/electrical system at the required slower rate.

When they start appearing in junkyards, a DIY conversion in another car will be possible. I suspect the hard part is in efficiently converting the voltages between alternator/capacitor and lead-acid battery.

[RedDevil]

Originally Posted by Occasionally6

It's only being use as an energy storage buffer isn't it? (...) The capacitor can take the rapid charge that the conventional battery cannot and bleed it back into the battery/electrical system at the required slower rate. (...)

True. It sure has its merits. And even though the energy stored is just a couple of wH, it saves a multitude of that by not having to run the engine for a while.

But it is complex and expensive. And only needed because the battery cannot charge fast enough, which may change in the near future.
For the time being, it will have its right of existence, as long as it is cheaper than adding a full hybrid system.