Poor mans regeneration with alternator relay.
 

I have been thinking of ways to reduce use of alternator to improve mileage. First thing I have an old 1966 car to experiment with so I will have minimum electrical needs.

so I was thinking of using some heavy duty deep cycle batteries so alternator power would not be needed all the time.

So then I thought what if I hook up the alternator with a relay that hooked into the brake lights. then every time I hit the brakes the relay kicks the alternator in at full output. to help slow the car and boost the batteries. then when you release the brakes alternator is cut out. Could supplement system with a solar panel in back window.
Just some easy ideas to try.

You might want to ask user rgathright for advice. He's running a Jeep with the alternator disconnected and using a deep cycle gel cell so he doesn't have to turn it back on; and he's using a power supply that makes sure there's always 14v, since some systems expect that much.
https://www.gassavers.org/garage/view/1440

I like the idea. I use the AC when I am in DFCO because the energy would be wasted otherwise.
With computers and knowledge of the times when efficiency is at a minimum, why not use the energy lost to friction braking to accomplish battery charge level replenishment.
In stop and go driving it would probably be possible to accomplish all battery charging with energy normally lost.
That is doubly effective from my perspective, energy wasted to energy recovered.
I know the concept of a combination starter and alternator is approaching commercialization. Maybe the application parameters could be expanded to allow some assistance from the integral starter-alternator for initial acceleration. A somewhat larger deep cycle battery (like a golf cart type but of a reasonable size) combined with the integral starter alternator, could provide automatic engine shutoff to eliminate idling as well as added power for a short period of time in initital acceleration.

Good thread.

regards
gary

You've just described exactly the system that GM offered on their full size trucks for a couple years. Of course it was too expensive to be viable, and it didn't sell. I'm not sure if that's the same system as their "mild hybrid" that's available on the Malibu.

I have a question, is there a relay to kick in the alternator at full output?

I thought it was just one output (one pulley), when the engine spins faster it makes more current... ??

Or is there internal gearing in the alternator to tell it to give it little, medium, or a lot of resistance?

The resistance comes from electrical load, that's why in some car you will see the RPM drop if you both light up the lights and turn on the fan full blast at the same time at idle.

Think of an electromagnet that gets stronger when you uses alot of power..the alternator does that when when theres alot of power usage.

Having no load on the alternator makes it act like a pulley basicly...if you had the chance to spin by hand an alternator you probably notice it just spins easily.

TO the original poster: You'd need a pretty expensive and heavy duty relay rated in the 60+ amps. or whatever your alternator output is.

An alternator probably robs about 1 horsepower of the car when used at full potential.

Good guess! One horsepower is ~746 watts. 60 amps at 14v (the usual voltage of a car with the engine on) is 840 watts. An alternator is not perfectly efficient, probably not even close, so I'd guess 2hp for a 60 amp alternator at full output.

It probably doesn't run at full output often or for long.

alternator starter concept
 

Yeah I saw that too here it is, looks like a pretty cool system but may be a bit costly.

https://www.gates.com/brochure.cfm?br...cation_id=4779

Actually you don't need a voery heavy duty relay because what you want to do is switch the rotor winding of the alternator on and off. that is what the regulator does, it regulates the amount of current going to the roto of the alternator and that determines how strong the magnetic field is of the rotor. when you set it to full power the alternator puts out full power.
depending on the alternator you would need to run a couple wiles to it or tap into the ones tah are going to the external regulator. I am working with an old car so no need to worry about computers and all that. only need to supply power to lights radio and ignition coil. Hows that for a minimalist? :-)
I plan on converting all the lights to LED lights except the headlights. So might be able to get by with very little current during daylight hours.

seems like a simple and effective solution. just wire the relay that you want to "full field" your alternator up to your brake light switch. it should draw more than 2 amps max. The only problem I see would be shutting it off automatically at idle so it doesn't draw power while you are sitting still.