TheSamba.com :: View topic - alternator wiring- i know beating a dead horse!

Fri Jul 13, 2018 6:59 pm

So guys- I have this vw type 1 based contraption that is running a alt.

it is wired the most basic I could find!

except NO dummy light in line off D+! I know everybody says it has to have a dummy light in the circuit! but this little contraption has been running for about 9 months without the dummy light- and has 100 hours on it and mostly night driving with a chessy led light bar on with no battery issues at all! Whats up with it charging fine with no dummy light? I know dale is the wiring guy- but anybody chime in!

Sat Jul 14, 2018 6:42 am

Basically the ALT lamp serves two purposes, one it provides a momentary 12 volts to the the alternator to initialize the voltage/current generation process.... Second it provides sort of a right resistance block for engine run on... Run on is where the output on the D+ is enough to feed back through ignition switch wiring circuit and allow the motor to run even after turning off the ignition switch....

The real question is how have you got it wired now...

Dale

Sat Jul 14, 2018 11:26 am

here is the switch I am using

back side of it

Dale/everybody the only diff in my wire set up from the one pictured below is I have the D+ going to acc pole by it's self on switch that stays hot while the key is on ( and no dummy light)..

I don"t know how or what- but do know this thing has been running with no batt issues!
I am looking to put a dummy light in so I know if I loose a fan belt and a added benny is knowing the alt is charging. so will any 12volt light bulb work- like a 1156 bulb? thanks for the help.

Sun Jul 15, 2018 8:11 am

OK.... Using ACC position on IGN switch eliminates "run on" because it disconnects the power generated on D+ of alternator from ignition circuit so no bleed through to cause run on...

Yes it works but a bit funky...

Another advantage of ALT lamp is it will indicate to you when you have lost cooling ( thrown fan belt)...

Dale

Sun Jul 15, 2018 1:03 pm

Thanks Dale-yes that is the plan for wanting dummy light is for the fan belt-can I just put any bulb in the that d+ wire like a 1156 single filament tail light bulb and it work correctly?

Edit- never mind with above said- I get that will not work! so how do I get a dummy light back in this deal.. wire it like you guys have said all along?

Sun Jul 15, 2018 2:51 pm

Small bulb into D+ line and to ACC position of ignition switch will work!... The thing is it just has to have 12 volts on one side of lamp and other side of lamp has to connect to D+ of Alternator...

Dale

Tue Jul 17, 2018 4:10 pm

Thanks, Dale.

Sun Aug 11, 2019 6:39 pm

So in my 73 Class 11 (kind of) type car, I replaced the original (motor) generator and under seat regulator with a different (motor) that has an alternator with the regulator mounted on top (not the internal one). Question is, does that alt d+ just go to the idiot light as normal, that is to say, use the same wire that was on the regulator under the seat going forward to the dash?

Sun Aug 11, 2019 7:59 pm

Yes....

Dale

Sun Aug 11, 2019 8:09 pm

Thanks 8)