Automatic alternator cut out/regen braking

[Bearleener]

My engine has an idle switch built into the butterfly valve assembly which the ECU uses to know when it needs to do its idle stabilizing thing. You could tap into that wire to know when you're coasting.

My alternator (Valeo, 90 A) unfortunately has internal field wires; the only skinny wire running out of it is the blue one going to the alternator indicator light in the dash. AndrewJ and psmithrt, are you sure that disconnecting this wire will turn off the alternator?

I'm a bit scared when using this technique that voltage peaks might fry the electronics.

Here's a good "Alternators 101" tutorial: http://www.autoshop101.com/trainmodu...or/alt102.html
More alternator circuitry: http://www.alternatorparts.com/under...lternators.htm

There should probably be a short delay after reaching idle before you re-engage the alternator so you don't get a little voltage blip every time you change gears.

[Bearleener]

My engine has an idle switch in the butterfly valve assembly that the ECU uses to know when it needs to do its idle stabilizing thing. You could tap into that wire.

My alternator (Valeo, 90 A) unfortunately only has 1 skinny wire going out of it: the blue one for the battery warning light. Are you guys sure that disconnecting this will turn off the alternator? May it will just disable the self-excitation circuit.

Alternators 101: http://www.autoshop101.com/trainmodu...or/alt102.html
More alternator circuits: http://www.alternatorparts.com/under...lternators.htm

There should probably be a short delay between reaching idle and switching the alternator back on to prevent a short voltage blip every time you change gears.

[psmithrt]

Originally Posted by Bearleener

My engine has an idle switch built into the butterfly valve assembly which the ECU uses to know when it needs to do its idle stabilizing thing. You could tap into that wire to know when you're coasting.

My alternator (Valeo, 90 A) unfortunately has internal field wires; the only skinny wire running out of it is the blue one going to the alternator indicator light in the dash. AndrewJ and psmithrt, are you sure that disconnecting this wire will turn off the alternator?

I'm a bit scared when using this technique that voltage peaks might fry the electronics.

Here's a good "Alternators 101" tutorial: http://www.autoshop101.com/trainmodu...or/alt102.html
More alternator circuitry: http://www.alternatorparts.com/under...lternators.htm

There should probably be a short delay after reaching idle before you re-engage the alternator so you don't get a little voltage blip every time you change gears.

No I am not sure about that wire. Infact my alternator is also all internal. From what I've read there are two excitation routes. You're second link confirmed that. Also I have'nt even pulled the 100 amp fuse on mine to confirm that my ECU will tolerate 12.? volts. Though I did see clearly where the main wire goes through the fuse box. I will pull fuse and check that first and then possibly think about using a relay at that point. Of course on the in side.
My plan still and always was to just interupt during load and acceleration. Mainly because I can use the same load sensing switch as I plan to use for a/c anyways. That and I really don't want or have the room for a true deep cycle battery which is the only way I would attempt cutting the alternator for longer periods. From what I've read, standard starting batteries due not like going much below 80% dod repeatedly and I just invested in a Optima red top 8 mos ago. I really needed the CCA's in central NY. If I were to go the other way Trojan has a 12v deep cycle that sounds up to the task of repeated 50% DOD. It seems to have at least enough CCA's for starting in most climates and I'm betting it is built more like a traction battery than any wanna be marine style.
Thanks for the alternator links:: PS, My homemade PCV condensor seems to be catching quite a bit of crap 1-2 Tablespoons in just 400 mi. almost as much as I've seen pictures of at 1-2k mi for the simpler compressor water seperator types. COOL

http://www.himacresearch.com/books/hydro8.html

[s2man]

A 100A fuse? That sounds like alternator output instead of field current. Most articles warn that disconnecting the output can damage the regulator.

On the dual excitation routes: I've read that some alternators are self exciting. When I disconnected the field current from my '96 GM alternator it stopped putting out juice. So I believe it does not have a secondary field current source. (lucky for me, as that makes it easy to control)

[psmithrt]

Originally Posted by s2man

A 100A fuse? That sounds like alternator output instead of field current. Most articles warn that disconnecting the output can damage the regulator.

On the dual excitation routes: I've read that some alternators are self exciting. When I disconnected the field current from my '96 GM alternator it stopped putting out juice. So I believe it does not have a secondary field current source. (lucky for me, as that makes it easy to control)

That is indeed the output. I believe mine is of the self excitation dual wire type. I figured that a relay at that output before the fuse may be the easier (maybe only) way for me to go. I have read articles about not disconnecting the battery and letting the alternator run the show as it can cause voltage spikes and other anomolies that the battery effectivly buffers. If you have an article link handy saying what your stating I would appreciate. Otherwise I will keep searching myself. It looked like a relay was going to add about 30-40 bucks to the 80 of the load detecting switch as it was, much more than that and I will just buy the gas. HA. Anyway I believe I am sol at the field coil wire. Anyone know of a cheap workaround other than my 100 amp relay at fuse box idea?? Thanks. Maybe I will just can the idea and start looking into cheap aero mods as I can probably get more bang for the buck anyway.

Hope all works out for you AXMAN and if you do find yourself with a dead battery in 3-6 months may I recommend a Trojan J150. It sounds pretty heavy duty and can be had for $180 US. Thanks s2man for the heads up!!

[rbhollabaugh]

1. I've noticed that most car electronics will work down to at least 9 volts.
2. Once I had a dead alternator. I would plug the battery into a charger overnight and then drive to and from work with no problems. Even into the night using the headlights. Each day I drove about 50 miles. Did this for about a month until I had the time to fix the car.
3. I think you are onto something here but the savings will be small but still worth going after.

[diesel_john]

Originally Posted by AXMonster

Circuits are built & ready to fit.
Both are supplied with relays fitted to the PCBs. Either can switch the alternator back in.

The system requires 6 wires:

Ignition switched positive
Earth (negative)
Positive voltage sensing wire to battery
Injector supply sensing wire (back probed from ECU output)
2 Field supply wires from & to alternator.

The field supply to the alternator needs to be cut and diverted to the control circuit, otherwise its easily removed.

The point at which the duty cycle is set to switch the alternator back on is programmable by push buttons on the circuit, as is the hysteresis. The duty cycle is displayed on a pair of 8 segment LED displays, which is on a long ribbon cable for easy dash mounting. The display also functions as the programming interface.

The voltage switch point & hysteresis is adjustable by 2 potentiometers on the voltage switching circuit board, and can be set to any voltage easily with a multimeter. An LED indicates when the voltage based switching circuit is operating.

Oh, and the LED duty cycle display is self dimming at night with a variable brightness control!

good work, let us know when you have it installed. i would like to do this. good possibilities.

[s2man]

Sorry, psmithrt. I don't have a link handy for that reference. I read so many articles, trying to find one specific to my alternator. I've got three wires: output, field, and remote voltage sensing (under the dash, where the accessories are, instead of at the battery).

[psmithrt]

Originally Posted by s2man

Sorry, psmithrt. I don't have a link handy for that reference. I read so many articles, trying to find one specific to my alternator. I've got three wires: output, field, and remote voltage sensing (under the dash, where the accessories are, instead of at the battery).

Thanks alot for the replies s2man and andrewj. Look forward to hearing how yours works out axman. Guess I can't do anything with the alt. on my Mazda.

Later

[diesel_john]

axmonster,
quote
The duty cycle is displayed on a pair of 8 segment LED displays, which is on a long ribbon cable for easy dash mounting. The display also functions as the programming interface.

I would like to display duty cycle, how did you make it?


Thanks