Put your thinking caps on and explain this. I put a new 105 amp alternator on a 40 Pontiac and the instructions said to run an extra wire straight from the BAT terminal on the alternator to the Positive on the battery if using an alt of more than 80 amps. I checked for charging before running this extra wire and the amp gauge read backward so I stood on my head and reversed the wires on the back of the gauge. I then installed the wire as instructed and the gauge read backward AGAIN. Baffled I disconnected the auxillary wire and the amp gauge read correctly. I now have a jumper from the alt to the battery + so I can quickly demo this to all the "brains" that drop by. No explanation yet. The alt is raising the voltage to 14.5 on the battery no matter which way the amp gauge reads.
Could it be as simple as the manufacturer knowing that the gauge would read backwards and the jumper wire was meant for people who wouldn't have been smart enough to switch the wires on the terminals on the gauge? Because, it sounds like, if you hadn't switched the wires on the gauge, the result would have been that it would have been correct.
I Get It Or at least I think I do : The ammeter reads the amount of charge by measuring the flow of current , this extra wire more or less balances the current . What gauge is the ammeter's wiring ? . One way or t'other , I'll learn from this ! .
Direction of flow Sounds to me like the aux wire is needed to keep the direction of current flow correct, you may be getting your flow down the aux wire and thats why the gauge reads backwards, you have not said that you tried it with the gauge wired as original and with the bat-battery wire in place, have you?
I think each one of you is on the right track. The by-pass wire was in a separate package and 14 gauge in size. I already had a 10g wire the right length so I used it. Without the engine running the head lights would show a distinct discharge on the amp gauge but the needle stays nearly centered when running. On a hunch I replaced the 10g wire with the 14G and the needle looks to be in a normal charging position. Naturally I couldn't let this rest so I tried both a 12g and 16g wire with the 12g moving the needle just off center and the 16g wire showing what one would call an over charging reading. Makes sense, the smaller the by-pass wire the more has to go through the gauge. I guess Tailgater's right about the company doing their homework which is a pleasant surprise nowdays.
Thanks, Evan~ I guess I need to get a new gauge. I was looking at a picture of my dash after I redid things. The needle has always stayed in the same spot. I'll assume it must be fried.
Ammeter Testing Not necessarily ! . First , remove the _Negative_ battery cable whilst watching the ammeter ~ if it twitches , you have a current draw that needs correcting before you touch the gauge . Ammeters are old tech that's not very good anyweays , as long as it points one way when off idle and t'other way when idling , everything is prolly jake , no worries . left , right , makes no real difference . I remember LOTS of Corn Binders that had buzzing cutout points in the voltage regulator , the ammeter needle vibrated *so* much @ idle , it was a blur . of course , this was ' normal ' for a 6 volt 'Binder and they all operated this way for 30 years.... .
Little Tip Some of you know this but for those that don't.....The best way to check for a draw is get a test light or meter then disconnect the Pos. cable from your battery connect one end of the test light or meter to the Pos. battery cable and the other end to the Pos. terminal on the battery. If the test light lights up or the meter gives you a reading then you have a draw that will eventually drain your battery. Faulty cigarette lighters and interior lights being left on are notorious for draining your battery......Big Tim
Thanks, guys~ I'll check it both ways this weekend. ANYTHING, just so I have an excuse to crawl back up under the dash!
