Alt kill switch planning (help)

[busypaws]

drmiller hit it on the head. I disconnected the connector with the 4 wires. I then made 4 jumper wires that reconnected the two connectors with 6 inch jumper wires with male/female spade connectors. Then I proceeded to turn on all the lights and accesories so there was a load on the alternator. I then disconnected the jumper wires one or more at a time to see what the alternator did. Output 14 volts or not. When I got the two connections that did what I wanted I then made a permenant connector and switch on the dash board that allowed me to open those two connections to turn "off" the alternator and "close" the connection to turn back on when needed.
Since you don't cut the two factory connectors off you can always diconnect your system and reconnect the alternator like factory if you ever sell it or take it to the dealership for service (or give your wife the car for a week or more).
You have to train yourself to keep track of the battery voltage -- you never want to turn off the engine without looking at the voltage guage to make sure it will restart.

[brucepick]

I think drmiller has a good plan.

You could "disconnect" the same wire by pulling the correct fuse (#15) under the dash. Just know that fuse also powers the vehicle speed sensor, so don't plan on driving with that fuse pulled. But it's a clean way to see what happens when that wire is disabled. If it does the job then you can put your "cut" where you prefer it.

My car still has a clear plastic sheet showing the numbers for those underdash fuses. If you don't have it, I suppose you can find the info somewhere. You'll need it one day when something stops working and you need to chase a blown fuse!!

[wakie]

don t forget to reactivate your alternator while your car is slowing down to a stop
if your car is in fuel cut-off it s free energy
(fuel cut off occur when you let the tranny in gear (manual) and the engine is revving over 1300 rpm with the foot off the gas pedal)
if you have any question about wiring in honda, i own shop manual of 88-2000 civic
feel free to ask

[California98Civic]

Originally Posted by brucepick

You could "disconnect" the same wire by pulling the correct fuse (#15) under the dash. Just know that fuse also powers the vehicle speed sensor, so don't plan on driving with that fuse pulled. But it's a clean way to see what happens when that wire is disabled. If it does the job then you can put your "cut" where you prefer it.

Oddly, I pulled fuse #15 in the under dash box and then one or two immediately adjacent to it. There was no change in the charging voltage on my dash mounted meter. It stayed at about 13.5 volts, instead of the 12.4 that the deep-cycle battery was showing before start-up. Wouldn't that imply that the other wires supply enough power to run the alt's field windings?

Just FYI, I am also trying the spade connector trial-and-error method. I made the male/female tipped wires, but the alt is in such an awkward spot that it's pretty tough to connect the female ends to the alt. I'll need daylight. So far I have failed.

[3dplane]

Try the same but this time shut your engine off and restart a few seconds later to see if it quit charging then.
I don't think it is easy to shut down a spinning alternator because even though you remove the power from the field winding (the electro magnet) the iron "claws" stay magnetised somewhat and it will keep re-exciting itself as it spins within the stator windings and it's iron core.

(This is why if I were to do this,I would probably go the other rout where I would interrupt the alt. output wire (going to the battery+) with a heavy duty solenoid.However then I'm dealing with having to supply power to this solenoid to keep it open or closed etc.)
Also try it with a bunch of electrical load on,at least that will show the voltage difference better when you get it to quit for you.

Barna

[drmiller100]

barna, I would really not recommend intrupting the big wire. bad idea.

A better way is to hook a light up to the field, then to ground. That way the field can gently ground through the light killing the field magnetics.

when you put power to the field, it will still energize the field, and turn the light on. LED's are not suitable for the light - it must be an old fashioned incandescent.

[3dplane]

Originally Posted by drmiller100

barna, I would really not recommend intrupting the big wire. bad idea.

A better way is to hook a light up to the field, then to ground. That way the field can gently ground through the light killing the field magnetics.

when you put power to the field, it will still energize the field, and turn the light on. LED's are not suitable for the light - it must be an old fashioned incandescent.

I like your grounding through a resistor(bulb) idea to bleed off field power! Especially if it works too! You probably have played with this more than I did!

What is so bad about cutting output current? Besides the obvious sudden current rush and possibly arcing across the solenoid contacts?
I believe the alternator would turn relatively free with output disconnected but I don't know how much dragging effect would be inside the alt. from eddies as the magnetised core (rotor) is spinning in the stator! ( try moving a large neodymium magnet along a hunk of aluminium or copper!amazing amount of drag!)I Have not tried messing with that yet on an alt.

I was also thinking of just limiting alt.output current by simply elongating the output wire by using maybe one of those cheap jumper cables (both wires in series) to add significant resistance between the alt.and batt. Yes there would be some waste heat but less output and less drag on the alternator! Have not tested this neither yet!Just throwing around ideas.
Barna

[drmiller100]

barna, making the wire longer just wastes energy. it will still try to get to the desired voltage, but will waste a bunch of energy doing it.

i'm a little puzzled about the whole alternator kill idea. how much energy are we really saving?

[deathtrain]

65+ Vehicle modifications for better fuel economy - EcoModder.com

Also a gain is a gain now matter how you put it. It just up to the driver/owner if that gain is worth the headache or not.

[California98Civic]

Originally Posted by drmiller100

barna, making the wire longer just wastes energy. it will still try to get to the desired voltage, but will waste a bunch of energy doing it.

i'm a little puzzled about the whole alternator kill idea. how much energy are we really saving?

Google MetroMPG alternator optional test. You'll see his pretty thorough results. I have been switching back and forth by unplugging the alt since September. It seems to be worth about 5% to me (not MetroMPG's 10%). But I already P&G so much that the alt is often not "on" anyway. I will say though that I run a deep-cycle battery, I greatly reduced electric loads, and I plug it in at night: i.e., the grid is my alternator.

Hope that's useful. Part of the plan for me now is to be able to strategically switch the alt "on" to coast down the huge hills around here in gear in fuel cut-off mode, charging the battery while using little to no fuel and extending the life of brake pads with engine braking to boot.