What I don't understand is why don't they put a small 20 kW 500 cc one cylinder generator in cars, at the same time they could reduce the battery size quite a lot and still most trips could be made purely electrically. Cost would be a lot lower as well.
The average power needed for driving is very low, only 10-20 kW and the battery handles the peaks like when you need to climb a hill or overtake. For example in this article they used 78.2 kWh in 5 h, meaning average 16 kW. The small generator could be called a spare energy source.
Instead, all plugin hybrids have big expensive heavy four cylinder engines which defeats the whole point of building a hybrid in the first place. For example 1.4 liters in the Chevrolet Volt / Opel Ampera.
And then Tesla has no high energy density backup source which again limits the usability of that car (and forces you to keep another car). And raises anxiety...
"why don't they" -> Remembers me of a recent HN discussion ;)
But... Actually you are not far from something. This is actually an approach from Audi: http://green.autoblog.com/2010/03/01/geneva-preview-audi-a1-...
From what I read though this approach was not approved in the mother company, VW. Let's see who wins at the end.
The average power needed for driving is very low, only 10-20 kW and the battery handles the peaks like when you need to climb a hill or overtake. For example in this article they used 78.2 kWh in 5 h, meaning average 16 kW. The small generator could be called a spare energy source.
Instead, all plugin hybrids have big expensive heavy four cylinder engines which defeats the whole point of building a hybrid in the first place. For example 1.4 liters in the Chevrolet Volt / Opel Ampera.
And then Tesla has no high energy density backup source which again limits the usability of that car (and forces you to keep another car). And raises anxiety...