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Old 04-08-2012, 09:54 AM   #1 (permalink)
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Altinator delete

Will disconnecting the battery stop the draw from the Altinator ?

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Old 04-08-2012, 10:19 AM   #2 (permalink)
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Disconnecting the battery will stop draw from the battery, if you try and run your car with the battery disconnected everything will run solely from the alternator (if at all).
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Old 04-08-2012, 02:21 PM   #3 (permalink)
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When the battery is fully charged it takes less than an amp to maintain system voltage.
Whats the point?
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
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Old 04-09-2012, 10:41 PM   #4 (permalink)
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Originally Posted by oil pan 4 View Post
When the battery is fully charged it takes less than an amp to maintain system voltage.
Whats the point?
I think that's true, as long as you're not running headlights or fan or stereo or whatever. Ohms law will tell you that low beams at about 60W each is 10 amps, just for the two bulbs. Plus a few more watts + amps for the smaller marker bulbs on front and rear corners.

But aside from that, I'm convinced that keeping the system at about 14V has losses that are noticeable. You can buy that electricity a lot cheaper off the grid, and use it to charge up a deep cycle battery.

Two loss sources I'm aware of:
  1. Heat generated within the battery keeping it at 14V vs. it's natural resting voltage of about 12-12.5 volts.
  2. Efficiency losses within the alternator. Notes in our "alt delete" threads indicate it's maybe 50% efficient at best. And the gasoline engine is also far less than 50% efficient, in terms of capturing the energy in the fuel. Something like 30% efficient, I think??

Anyway, with my alternator disconnected, my little Civic has more power available at the low throttle positions I mostly use, for getting up hills. Because it's not driving the alt to keep the system at 14V.
Coast long and prosper.
Driving '00 Honda Insight, acquired Feb 2016.

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Old 04-09-2012, 11:36 PM   #5 (permalink)
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If you remove the battery while the car is running you can completely fry your electrical system almost instantly. The battery acts as a buffer and is required for proper operation of the alternator. The alternator actually produces 3 phase AC and this power is converted in the back of the unit to DC through a series of electronics, diodes and capacitors. You could fry them, your computer or a dozen other things if you do.

Don't Disconnect the Battery with the Engine Running


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Your grammar is appreciated.

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