my dad is restoring my datsun 1200 and he has come across the problem of the head lights are draining the battery when he drives it does anyone have any ideas what may be causing this and how to fix it?
before he takes it to the auto electrics next week

cheers!

what engine a12?

1200 engine, he said that the voltage regulator was running ok yesterday but when he had the car running the battery was getting drained so he wanted to get some more ideas why it was draining it.

First thing would be to check the alternator

then look for a loose connection causing a short,

also if its a wet cell battery, is there water in the cells,

Don't mean to sound silly but check the obvious things first.

when the lights r on?
could b a short in the lighting circuit causing battery drain...
is battery new?
fan belt could b slipping,
terminals could b loose or corroded,
alternator not charging,
battery plates could b severley sulphated
or the regulator unit not working correctly...

alternator is ok charge light goes off

battery is brand new

no loose connection that he can see

he said it may be the voltage regulator but not too sure?

yeah because he has checked all obvious first he has a few more ideas what it could be but just wanted a few more ideas before paying someone to look at it....

Quote:That's a good sign, but it could still be bad. The best way to test this is with an inexpensive voltmeter. At 1000 rpm or more, the battery voltage should be 13.5-14.5 volts. If it is below 13.5 volts, the regulator is probably bad. If it is below 12 volts, the alternator may be bad.

has he checked the contact point gap on the voltage regulator? should b between 0.012 and 0.016in.

EDIT - pretty sure that's right... ddgonzal? got manual layin round here some where i'll double check...

Is checking the gap necessary when the voltage is correct? Or should you only check the gap if the voltage is incorrect?

Here are the details on checking the regulator: wiki - Voltage regulator.