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Alternator use and output Answered

Hail the reader and Bless the respondent. please can someone tell me the following 1. At what speed must a normal vehicle alternator turn to give max output... and what is this out put... I see my charge meter shows it charging at 10 amps... how long to fill the battery at 10 amps? 2. A pack of 6 12v truck batteries connected to make 1 big 12 volt battery... is it possible to charge this pack from more than 1 alternator and will it speed up the charge time to make the battery full to max?

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NachoMahma (author)2009-01-03

. The alternator usually spins faster than the engine. I'll guess ~3x faster, but that could be way off. Most auto alternators need to have the engine turning at 1500-3000 to give full output. Lots of variability; depends on the application. . Automotive ammeters are notoriously inaccurate. Pumping 10A into a car battery for very long will overheat it. . The time to charge will depend on the battery and it's state of charge when you begin charging. Your charger will not will not put out 10A for very long - as the state of charge increases, the charging current decreases. . . Yes, you can do it, but you will need a controller to balance the loads. . Probably. If one alternator/charger is big enough to do the job, adding more won't do any good (batteries will accept a charge only so fast; if you charge them any faster, they overheat.), but, for a fast charge, most car alternators won't handle six batteries. You can probably find a high-output alternator that will handle six; check RV and car stereo stores. . BTW, it the alternator doesn't have a built-in regulator, you will need that, too. . . What will you be using to drive the alternator? If an electric motor, it may be easier to buy/build a charger designed for multiple batteries.

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carnut34 (author)NachoMahma2009-01-03

thank you for the interest. We are building a prototype electric car (i am the accountant and not to up to scratch with electronics, but i have the believe that if we drive this car on the open road using a wind vane to drive an alternator or generator we can use this to ibcrease the distance by adding power as we go!! All cars have fans at the radiatow, thought a similar type of fan to do the alternator turning??? Love to ghear your comment. Thank you and thank you again for the interest

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NachoMahma (author)carnut342009-01-03

> i have the believe that if we drive this car on the open road using a wind vane to drive an alternator or generator we can use this to ibcrease the distance by adding power as we go!! . Sorry, but it's not going to work. :( You will lose more energy from wind resistance than what the alternator will put out. You can't win; you can't break even; there's always a loss.

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kelseymh (author)NachoMahma2009-01-03

An accountant should understand thermodynamics at least as well as a physicist :-/ There is no free lunch.

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NachoMahma (author)kelseymh2009-01-04

. heehee Had to read your first sentence twice before I got it. Everything has to balance.

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