I sent this to 'Stevie' through Nabble and thought it was worth posting here for the benefit of any future wannabe alchemists. I hope there are no glaring errors in it!
Stevie, Hi - fellow Brit (Herts) and vaguely experienced DIY EVer/loon etc. >From your posts I gather you want to recover electrical energy from your >moving car by running an alternator off the rear axle whilst powering the car >from an electric motor attached to the front axle... ? Assuming I have it right, sadly, this just won't work. If it did, it would be an 'over-unity' device or equivalent to 'free energy' or 'perpetual motion' - all are contrary to the laws of physics (as we know them). EVers are a bit tetchy on this subject and tend to react badly when someone (yet again) raises the subject as if no-one had ever thought of it before... sorry if that sounds rude! If you are struggling to understand why it won't work - and to be fair, at first, most people do - imagine doing what you suggest to a bicycle. Your legs power the rear wheel as usual but you have a socking great dynamo (or alternator suitably geared) on the front wheel being driven by the wheel rotating on the ground. Any electrical energy you get out of the front wheel is going to have to be supplied by YOU! And at a relatively poor efficiency (70% or so) at that. The only way this makes any sense is to use the forward motion of the mass of the vehicle and its contents (kinetic energy) when slowing down or doing a controlled descent of a hill to generate electrical energy that is fed back into the battery. This can be achieved in the way you suggest or more easily and cheaply by using the wheels to turn the main propulsion motor of the EV in reverse. This is called 'regenerative braking' and is implemented on most production EVs very simply due to their use of AC motors which are 'reversed' very easily. It can add up around 10% to the range of such an EV, particularly in constant stop-go (ie city) driving. It is still possible to do this with the more common DIY EV DC motor but is considerably more complex and therefore expensive. I hope this has cleared this issue up for you and I have taken the trouble to contact you with this as I know how frustrating this mis-understanding of the real world can be. If you want to post on the EVDL as opposed to just the Nabble thing have a look here. I don't know if it would suit your needs but Peugeot were doing their version of the Mitsubishi iMiev, they call it the Ion, for £13000 all in including the ChaDeMo 30 minute fast-charge option a few weeks ago. Looks like its still on offer... http://www.marshallweb.co.uk/peugeot/newcars.asp?make=peugeot&model=ion Alternatively, the much nicer (IMO) and somewhat bigger Renault Zoe launches over here later this year at £13.5k plus £70/month for the battery but the milage is limited - don't know the details but it might be worth talking to them anyway. Good luck. Regards, Martin. www.evalbum.com/2092 On 15 Feb 2013, at 18:46, Voltswagon wrote: > Pretty sure the laws of physics apply as well in the UK as in the US. > > If you charge a battery using an alternator driven by the battery you're > charging you'll just waste an extra 25% of your energy. > > You don't get power for free. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
