voltage, wiring or alternator issues?

ronin-sj410 · May 18, 2014

First, you guys are always great at helping so thank you.
I have an 82 samurai with a 22r motor. The issue I'm having is I recently installed a voltage meter and I noticed while the engine is running it sits at 13.5v but when I step on the breaks voltage drops to about 11v and returns to 13.5 immediately after releasing. Is this normal or do I need to do some wire chasing.
Wiring is as follows:
voltage meter connected directly to battery. Signal wire for alternator connected directly to battery(I know this causes a drain but it's a trailer queen and terminal is disconnected when not driving), charge wire connected directly to battery. Taillights are standard 1157(?) brake/turn bulbs. Also I have noticed that my winch looses power after being ran for more than a few mins with a load on it which is also connected directly to the battery.
Any ideas or help is greatly appreciated. Thank you

Binder · May 18, 2014

First off your rig is wired about as ghetto as it could possibly be.... Voltage dropping for a second here and there isn't such an issue. The way it's wired you're never going to get a accurate reading anyways.

ChopTop84 · May 18, 2014

take it to an autoparts store and have them test the output of the alternator. Should be about 14 volts while charging, but if it drops big time when a load is applied (such as brake lights) then the alternator is probably taking a crap. or, you have the alt wired wrong and its not putting out any charge.

t1h5ta3 · May 18, 2014

sounds like a combo of bad grounds, improper location of the voltage sence wire etc.
charge lead to the bat is no big deal, sence wire and voltage gauge should both go to keyed on power from the ignition switch.

what you have going on is the alt never sees the load from every thing else it just see's its own output. when you hit the brakes you create a load thru a switch that is known for high resistance and voltage drop. that and if i recall sami's use switched grounds on the tail lights just like they do on the headlights....
so improper wireing, bad grounds, high resistance in the wireing.... ether tear it out and re do it right, set fire to it and claim the insurance, or live with it...

ronin-sj410 · May 18, 2014

Binder- suggestions???? Like how would you wire the voltage meter, the winch and alternator
Chop top- I have had the alternator tested and they said it was good and producing 13.8v, I don't know if they did a load test on it. The only time I get a voltage drop is when brakes are applied, none from headlights or highbeams or wipers, or stereo. Is there a need for more than the signal wire to the alternator. I was told since it is internally regulated that the two wires needed were voltage sense and charge wire.

ronin-sj410 · May 18, 2014

t1h5ta3 said:
sounds like a combo of bad grounds, improper location of the voltage sence wire etc.
charge lead to the bat is no big deal, sence wire and voltage gauge should both go to keyed on power from the ignition switch.

what you have going on is the alt never sees the load from every thing else it just see's its own output. when you hit the brakes you create a load thru a switch that is known for high resistance and voltage drop. that and if i recall sami's use switched grounds on the tail lights just like they do on the headlights....
so improper wireing, bad grounds, high resistance in the wireing.... ether tear it out and re do it right, set fire to it and claim the insurance, or live with it...

This makes sense... So I will rewire the gauge and sense wire to a key on location. Should I be concerned about amount of voltage/amps going through the voltage sense wire...should I increase the gauge of wire and fuse size on the key on wires I use.

ronin-sj410 · May 21, 2014

It appears I mis named the wiring I wrote about. When I wrote voltage sense I should have wrote exciter...turns out the wiring for the alternator was wrong and I do need to have a voltage sense wired to the battery which I was told I did not need... all is well now and no longer have a voltage drop on ANY accessorys. Thanks for the info:awesomework::beer::beer:

ChopTop84 · May 22, 2014

ronin-sj410 said:
It appears I mis named the wiring I wrote about. When I wrote voltage sense I should have wrote exciter...turns out the wiring for the alternator was wrong and I do need to have a voltage sense wired to the battery which I was told I did not need... all is well now and no longer have a voltage drop on ANY accessorys. Thanks for the info:awesomework::beer::beer:

That sounds better. The last ALT I had to wire up was a ford 3G, and it has a main charge wire, a key on wire, and then a small loopback wire that attaches to the charge post, then loops right back to the ALT on another stud. Ford's version of a "one wire alt" I guess.