Quote:
Originally Posted by steffen707
...I've read that while driving, once the field is energized even if you disconnect that power wire it will remain energized and keep charging. Also I heard from brucepick that he disconnected his 4wire connector from the alternator completely and after a few minutes he was still reading 14v.
I've got a few questions. First, Stinger makes a large 80amp capable battery isolator "relay", I could use this to disconnect the alternator from the battery on the fly, but if the alternator is charging the battery and you just disconnect that connection, will that harm the alternator?
Second question is if anybody knows how the ecu tells the alternator to stop charging on these civics?...
|
The diagram in the "...Your Vigor's..." link seems to match our Civics. Four "control" wires going to one connector plus one heavy power lead to starter + battery. None of the four small wires is a ground; that is via chasis/mounting bracket, as the Vigor diagram indicates. Our system is five wires total, and none of them is a ground. The four wire (total) setup in the "ND alternatordiagrams.pdf" link doesn't match what I see on our Civics, sorry.
After disconnecting my Civic's 4-wire connector, the system first showed approx 12.5 volts and dropping, but after a minute or two it came up to ~14V and stayed there. I've read that the 12V supply to the field coils (this is pretty standard alternator circuitry nowadays) activates them immediately rather than eventually, and that seems to be the case for our cars. California98Civic's approach was different; he severed one wire (with a dash switch I believe??) and left one other disconnected permanently, and got a way to disable and re-enable the alt on the fly. Slick.
I considered using a high-current-capacity relay to disconnect the alt power cable but decided against it. Nearly all relays require some amount of constant voltage to hold the switch contact closed (or open, depending on the relay design). [The exception is the uncommon type that works like an old fashioned ball point pen - pulse it once and it's on, pulse it again and it's off, ad infinitum.] In other words, aside from that uncommon type, you'll need steady battery power to keep that switch either on or off. Not my idea of conserving battery power. In my case I activate (and deactivate) the alternator rarely enough that I'm willing to go under the hood to change the switch over, and to manually connect or unplug the 4-wire connector at the alt at the same time.
That said, I'm quite curious to find out the results of trial-by-error experimentation by the folks in this thread. If it's feasible to disable the alt by manipulating some of the four smaller wires, that would be preferable to switching the heavy cable on/off manually, and manipulating the small wire connector at the same time.