Electric car: DIY!

Isn't that why some designs use ultra capacitors in parallel with the batteries?

Incidentally, on the DIY front, did you see the "Scrapheap Challenge" episode (renamed "Junkyard Wars" in the US) where the teams had to build (from scrap) an electric offroader in 10(?)hrs?

 

Here Frank, this might be of interest to you.........

http://volt914.blogspot.com/

 

Capacitors won't help in getting high sustained power. They only help with peak transient response.

 

Ultracaps are there mainly to help you start the engine, since that's the moment where loads of current are drawn from the supply (huge curent peak causing a short voltage drop when you crank it).

 

But surely most of the time you only need full power for short bursts**, say, from start to 60kph. If we assume a 1.5 tonne vehicle that would require about 208kJ of energy. According to this page, you can get, for example, a 48.6V, 144F module which should be able to store up to 170kJ. With a few of these and even only being able to extract 50% of the power, you should be fine.

Mind you, I've no idea how big/heavy these modules are!


**Unless you are boy racer.

 

Their datasheet seems to suggest 500g/.5kg, if I got the right part number.

That seems really really light, so I'm suspicious.

edit: and I should be. Their largest module is more like 16kg.

 

Sorry, that's what I meant. I still think you could have a charging system where you just park nearby and it automatically positions an induction loop close enough to get high efficiency in the transfer.

I missed your reply earlier, but energy density has everything to do with it, because my post was entirely about RANGE.

A whopping 565 pounds for only 4.5 gallons worth of range is inadequate for an electric car. That's why I agree with you that PHEV is the way to go. Of course we still have the problem of revamping the power grid to get off fossil fuels, so hopefully nuclear and/or some renewable miracle (CIGS solar and floating wind power are the only realistic possibilities, IMO) materializes.