[algea07]

I really want to build an electric car, but it is not uncommon for me to make long trips, sometimes traveling more then 200km several times a month. because of this i would need to have a separate ice car to make these longer trips. Something that i think would be a waste of money, why spend all that money on an electric car then still have to pay for maintenance and registration for another car.

I thought the easiest way around this would be to build a petrol generator and build it permanently in to the car. This means that on my daily trips into and out of work i can run of the batteries (22kwh), but on the longer trips i can switch on the generator and still get good economy (<6L/100km).

but it didn't take long for me to realize that such generators do not exist so, i've been trying to find away around this, and i think i've come up with a few possible solutions.

i don't know much so i'm sorry if any of you end up banging your head against your desk as you reed this, but here they are.

buy one of ebay: this is buy far the cheapest, i can get them for about $500. but they produce 240 3 phase AC. i thought that if i bought a 3 phase rectifier of ebay i could turn that AC to roughly 300v DC. then all i would have to do is build my packs max voltage at a level a little higher then that., and wolla hybrid vehicle. although i would probably need at least two. (at 10kW and 300v they only produce 33amp is this enough?)

Build one using an ac motor and controller: I'm almost certain that this would work, buy a 2nd hand motorbike engine and connect the ac motor and run it in Regen. but this would be expensive. so firstly would this work and could i do it without a controller? this setup as far as i know is similar to and alternator and they don't have a controller yet produce the right voltage.

Build one using a permanent magnet dc motor: basically the same set up as the ac. i would need a big heavy motor capable of producing at least 144v and i could buy a Kelly controller for a reasonable price.

so any opinions are welcome. you time is greatly appreciated.

if this cant work feel free to tell me, all it means it that i'll just end up building a lighter sportier ev.

 

[algea07]

what happens if the voltage generated buy the generator is less then pack voltage?

say for example i have a max pack voltage of 150 and the generator can only produce 144, and i turn on the generator before the pack has dropped bellow 144v.

 

[todayican]

I'm working on essentially the same thing. What I am going to do is set it up as a parallel and serial hybrid..

Here is what I mean: Connect the ICE to the drive line (my car is actually a trike so ICE to Centrifigual clutch to second sprocket on the drive electric motor.)

Size the ICE so its about 125% of the cruise needs at its peak efficiency (80% of peak hp in my case, Im using a 10hp diesel, souped up to 12hp with a small turbo)

Then, use a brushless permanent magnet motor and a controller with regen. Use the regen function to act as a generator and voltage regulator to charge the pack.

 

[jk1981]

what happens if the voltage generated buy the generator is less then pack voltage?

say for example i have a max pack voltage of 150 and the generator can only produce 144, and i turn on the generator before the pack has dropped bellow 144v.

In its simplest ICE-generator_set form the ICE will run unloaded, assuming the throttle is open sufficiently its RPM will either rise until generator output minus rectifier drop is above pack voltage, the rev limiter kicks in or something flies apart with a bang. Getting it to run efficiently will realistically require a closed control loop of some sort.

 

[Jason Lattimer]

This has been done before. Can't find the site right now though, it could go something like this.

Figure out how much horsepower your car needs to maintain speed.....generally most cars need about 20 horsepower to maintain 60 miles per hour.
Then go get a Zivan NG-5 and the correctly sized generator. I would say that combo and a 15 kw off the shelf generator( which I would put on a trailer and leave at home when I'm not using it) would give you enough power to maintain freeway speeds as long as you have gas in your generator/trailer.

And by putting it on a trailer, you get to subtract the weight penalty of having a generator weighing you down until you need it.

 

[algea07]

Then go get a Zivan NG-5 and the correctly sized generator.

i was hoping to avoid using a charger, if i can convert straight to DC then i should be able to charge the pack without a charger, this way i can save the money on the charger and the precious watts that might be lost in the charger. if i can do that with 3 phase rectifier then, it is buy far my best option.

i think i will mount under the bonnet, it won't make a huge difference to the whole weight of the car, and if i loose some boot space to a battery box then so be it.

 

[algea07]

I'm working on essentially the same thing.

yeah i already saw your post, good to know that a pm motor should be able to function as a generator for a prolonged time, do you know what efficiency you're likely to get out of it for Regen?

 

[todayican]

Spoke at length with the controller people who say the Sevcon Gen 4 is 94% in drive and the same efficiency in regen.