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Old 02-11-2012, 10:51 AM
dantheman dantheman is offline
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Default Can alternators charge EV batteries?

I recently had the opportunity to drive a friends Nissan Leaf. I loved it.

I know nothing about Electric Cars but was wondering why you couldn't charge the batteries with an alternator of some kind. I think this seems fairly obvious so I know there is an answer to why you cannot. Just haven't found it yet...so...could someone versed in Electric Car Motors explain that to me? Thanks.
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Old 02-11-2012, 11:09 AM
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mora mora is offline
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Default Re: Can alternators charge EV batteries?

Do you mean charging using alternators in fully electric vehicle while driving? Guess where the power to run the alternator comes from? Batteries. Motor needs power to turn and alternator also requires some power to keep going. It will never be 100% efficient (power in = power out + losses) There is always some loss of power somewhere in the way. You could charge 12V battery using alternator like in any gasoline powered car though.

Now if alternator is powered by another gasoline engine that's whole different story.
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Old 02-11-2012, 11:32 AM
dantheman dantheman is offline
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Default Re: Can alternators charge EV batteries?

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Originally Posted by mora View Post
Do you mean charging using alternators in fully electric vehicle while driving? Guess where the power to run the alternator comes from? Batteries. Motor needs power to turn and alternator also requires some power to keep going. It will never be 100% efficient (power in = power out + losses) There is always some loss of power somewhere in the way. You could charge 12V battery using alternator like in any gasoline powered car though.

Now if alternator is powered by another gasoline engine that's whole different story.
Hmmm...I see...I guess that is what hybrids do? My wife has a Honda Civic Hybrid.

Thanks for that obvious answer...makes total sense.
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Old 02-11-2012, 12:22 PM
MN Driver MN Driver is offline
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Default Re: Can alternators charge EV batteries?

Yeah, it's a fairly common question here. Most people don't realize that an alternator puts a pretty strong drag against the engine in a normal car causing it to consume more fuel than if it wasn't there. It doesn't just spin like people think it does.

In order to waste less gas and to produce electricity while in auto-stop, your wife's Accord uses a DC-DC converter and doesn't have an alternator. I don't know if any hybrids do, it is possible that some of the early GM hybrids do but their 36 volt systems don't do much more than engine idle auto-stop anyway and so the GM models never got very popular or much more fuel efficient than other cars as far as I can tell.

For the most part, the idea behind a hybrid is to use a smaller engine so you can keep the engine under a higher load while cruising which gives it better gas mileage. Stopping the engine when it would be idling also can save a significant amount of fuel. The batteries and electric motor(s) in hybrids assist the car to provide extra torque that a smaller engine doesn't have so the driving experience isn't reduced by having a less powerful engine. I like how Honda setup its hybrid drivetrain, it is simple, low cost, and very effective way to do it. I drive a 2000 Insight and love it, and with reasonable mostly highway driving, I get 70+ mpg tanks in the summer and a 1st Gen Insight will be my conversion to electric. I've measured out battery space already and have decided which motor I'd like to fit. I like the Nissan Leaf too but the auto manufacturers could do better in terms of efficiency(my goal) but right now the major manufacturers are aiming for mainstream or slightly higher-end acceptance and I don't blame them which is why I'll convert mine instead of buying what they are selling.
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Old 02-11-2012, 12:58 PM
icec0o1 icec0o1 is offline
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Default Re: Can alternators charge EV batteries?

Quote:
Originally Posted by dantheman View Post
I recently had the opportunity to drive a friends Nissan Leaf. I loved it.

I know nothing about Electric Cars but was wondering why you couldn't charge the batteries with an alternator of some kind. I think this seems fairly obvious so I know there is an answer to why you cannot. Just haven't found it yet...so...could someone versed in Electric Car Motors explain that to me? Thanks.
They do, it's called regenerative breaking and the alternator is the drive motor.
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Old 02-11-2012, 06:04 PM
Wild Wild is offline
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Default Re: Can alternators charge EV batteries?

Now take that alternator and make it into a wind turbine and set up the necessary electronics and a battery bank you can then charge that leaf.
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Old 02-12-2012, 12:42 PM
piotrsko piotrsko is offline
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Default Re: Can alternators charge EV batteries?

But NOT attached to the car.
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Old 02-13-2012, 06:00 PM
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rmay635703 rmay635703 is offline
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Default Re: Can alternators charge EV batteries?

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Originally Posted by piotrsko View Post
But NOT attached to the car.
I have seen several non-electric model cars drive into the wind with a turbine on top, the gearing you need to do so, is such that you move very slowly though.
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Old 02-14-2012, 07:46 AM
Wild Wild is offline
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Default Re: Can alternators charge EV batteries?

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I have seen several non-electric model cars drive into the wind with a turbine on top, the gearing you need to do so, is such that you move very slowly though.
Yeah let's get serious already.
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Old 02-14-2012, 07:58 AM
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Ziggythewiz Ziggythewiz is offline
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Default Re: Can alternators charge EV batteries?

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Originally Posted by rmay635703 View Post
I have seen several non-electric model cars drive into the wind with a turbine on top, the gearing you need to do so, is such that you move very slowly though.
It doesn't really have to be slow, you can go as fast as the gearing will allow, the key is you can drive into THE wind (which is a massive power source). You cannot drive into your own wind using this method.
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