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Discussion Starter #1
After not driving it for some time, I took the Elise out for a spin (on rather a wet day, and after a number of other wet days). It was not long before the battery tell-tale light came on at which point I turned back. Shortly after that the electrical power began to fade - lights dimming, wipers slowing etc. - before the electrics cut out altogether, then cut in and out after that. I got back home and left the car for a bit and now when I try to start it it just clicks from the rear as if flat and for some reason the headlights come on.

Could this just be a flat battery/faulty alternator etc. or may it be some type of electrical fault? If it is an electrical fault how difficult/expensive would that be to fix?

Cheers to all in advance for help - I am constantly impressed with the Lotus knowledge on this forum and it has been invaluable in my journey to understand my own Elise.

Martin
 

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Sounds like an alternator issue of some description. Either the alternator its self, regulator, diodes or slipping belt. Of course it could also be bad connection. My guess is that if you either jump started or charged the battery it would start, immediately removing the jump cables, it would die. Once it is running put a volt meter across the battery terminals and if the alternator is charging it will read about 14.2 volts.
Good luck,
Michael
 

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+1 for a charging fault.
If you follow Michael's instructions and you are not seeing 14V+ across the battery terminals with the car running, start with checking the electrical connections (including grounding) to the alternator. If you can't find anything wrong, you may have to remove the alternator and have it tested--most auto parts stores can do this for you these days.
 

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I have seen that while driving on very wet days you may get water on the alternator and then it fails to charge, charge the battery and let the car dry and check voltage before starting the car ~ 11-12V, and ~14V after the car is running
 

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We're assuming you checked the battery cable connections, s/b tight and clean.

If you get/have a digital voltmeter (which I can't do without), you can do a voltage drop test between battery and cable (or any other two points with power).

First ck the cables, then see if - when running - you are getting 14.2 or so volts to the battery.
 

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My experience is that if the battery has enough juice to start the car, and then the car falters while driving, it has something to do with the charging system. -especially if the battery has nothing left it in afterward.
Having water in the equation adds uncertainty, but rain shouldn't be a problem for our cars.

I'd definitely check your connections - not sure how well (or if) the Elise does running if there's no battery power, or how bad it could be for the system if it's just running off the charging system alone. (in the old days, on older cars, it could fry the voltage regulator - which is now built into the alternators I believe)

Batteries are easier to diagnose - if you can crank and start the car in the evening, and the next morning it it's dead - it's the battery.

In the old days it was easy to diagnose if it was the charging system, - start the car, and disconnect the battery while it's running. If the car stopped running it was the charging system.
 

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Discussion Starter #10
There was nothing coming from the alternator at all. Engine started on jump start then when the leads were removed it just died. A new alternator is on its way!

Martin
 

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There was nothing coming from the alternator at all. Engine started on jump start then when the leads were removed it just died. A new alternator is on its way!

Martin
Martin,
Thanks for posting the results :) Just watch the battery because they start to degrade after being discharged so deeply.
Michael
 
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