forgive the lack of understanding.....

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forgive the lack of understanding.....

Postby Chimpchoker » Tue Mar 24, 2009 8:24 pm

Something is going round my head and it's doing it in. Please forgive the lack of understanding but here's the problem.....

With a combustion engine you have the fuel, the motor and the battery to pwer the lights / start the veichle etc.

On an EV you have the fuel... the battery pack, the engine... motor and a battery for the lights etc.

Presuming the alternator charges the battery up on the combustion engine ok why can you not charge an EV battery pack with an alternator ?

I've thought it might be down to charging / discharging at the same time and also the alternator not being big enough to charge say 12 batteries.....

Go on someone put me out of my misery please......


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Re: forgive the lack of understanding.....

Postby Wilfried » Tue Mar 24, 2009 9:44 pm

[quote="Chimpchoker"]Go on someone put me out of my misery please......quote]

We take a battery connect it to a electrical motor and this motor we connect to a alternator (dynamo). And it will turn (normally) but...
In the motor we transfer only ,let say , 90% of the electrical power to mechanical power (mechanical loss, heat loss ...).
In the dynamo (alternator) again we have losses.
So sooner or later the battery get flat, the engine stops.

In a combustion engine our fuel is the source of our power, if you are out of fuel your engine give up.

Your idea is not new. Go and look after perpetual motion.

But keep in mind, there is nothing like free energy.


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Postby GregsGarage » Wed Mar 25, 2009 9:30 am

There is no reason you can't use an alternator to charge a battery, but probably not in the way you imagine. A typically EV has 2 separate electrical systems. A high voltage traction pack and a 12 volt system for the lights, etc. This is done for safety and convenience. Isolating the traction pack from the vehicle reduces the risk of a electrical shock and if you are converting a car it will already have a 12 volt system. So you could mount the alternator on the motor to keep your 12 volt battery charged, this would save the cost of having a DC-DC converter to keep the battery charged.
Greg Fordyce

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