Flickering headlights

[winger300]

im really not sure about this anymore!!

I tested my battery using a hydrometer, and it measures in the full/good region. So i can rule that out. I put some of those tablets in and topped up the water also.

I measured the output from the dynamo terminals shorted together, its putting out a good 20-30volts so im happy thats ok.

The battery terminal voltage when revving is 13-15v so im happy that its being charged.

I replaced the terminal box anyway using another i found in a box in the garage. It looked new, and had a Lucas guarentee. Installed it, and the ignition light now doesn't go out! The voltage across terminals D and E is only 1v. So something is messed up with the new regulator. Should these come setup correctly? or do i need to set the open terminal voltage?

Anyway i put the old regulator back and it works. Perhaps my problem is that im just doing short journeys 5-10mins, an occasional long run with cdplayer, heater and lights.

Also my wipers stopped working altogether, i had it all apart and it was really stiff, so maybe the wipermotor was drawing far too much current.

Perhaps an alternator is really the answer.

[rayofleamington]

im just doing short journeys 5-10mins, an occasional long run with cdplayer, heater and lights.

Mine does that, and also long periods of non use, and hasn't been a problem at all.
Maybe your CD player draws quite a few amps? As you mentioned it is worse after a long run then that could be related - If the charging system is ok, then the battery would normally be ok after a long run.
Car stereos can be run with a Dynamo, but if you draw a lot of current it could be too much.

[winger300]

i checked the regulator box output again today. It appears the open circuit voltage (Connecting A and A1 terminals together, voltage from D terminal to earth) was at 11-12v, whereas the haynes manual seggests it should be 16v.

Also the cut-off voltage was about 7v, so i adjusted that upto the 12-13v that the manual suggest.

We'll have to see if it has improved things. With any luck i've not totally messed things up

[Willie]

WINGER...you say that" when the car is moving all the electrics
are fine but things switch off when the car is stationary". This seems
to indicate that the dynamo is working Ok and that the fault is in
the battery or charging circuit. An Ammeter would tell you what
is going on within the first five minutes. Since you started off
with 'flickering headlights' and my motto is 'think simple' haveyou
checked the earth strap from the gearbox cross member to chassis?
Are your battery terminal connectors the clamp type(good) or those
horrible 'cup'type which are held on by a central screw(bad), (they
go high resistance) and finally have you checked the terminal
bolted to the bulkhead behind the main wiring loom several inches
below and to the right of the fuse block? This is the earth for the
control box and can give awful troubles. If there is a problem
with the earthing strap you will usually find that when you start
the car the CHOKE cable gets too hot to touch! because is is the
only other chassis to engine connection!

[winger300]

Thanks for the reply Willie.

The flickering lights were due to loose connections on the dynamo. I sorted that out, and now the dynamo output seems fine.

I think the battery is ok, its a couple of years old, but i tested it with a hydrometer, and it measures good.

The battery clamps are new clamp types, i replaced them when changing to negative earth. Control box earthing looks ok, and since i've adjusted it the output is about right. I think the problem lies with the adjustment of the regulator.

[Willie]

I would personally subject the battery to a 'discharge test'
before assuming it is ok, but failing that, an Ammeter,fitted
temporarily, would quickly tell you if the charging circuit is
faulty. After starting it should read a 'charge' of at least
20 amps which would quickly drop down to a lower figure.
If you then turned on say the wipers or the lights the meter
should lflicker then return to the original reading,i.e. it has
compensated for the extra load. You should be able to turn on
both the wipers and the headlights and still produce a 'charge',
( at reasonable revs) if it shows a discharge then your dynamo
or regulator appear suspect.

[winger300]

after my tweaking efforts to the Regulator box it seems to have solved my problem. No flat batteries since

[Arfron]

Check all your earth points for corrosion etc . Especially the 2 front earth points on the inner wing section , near the horn and 'tother side Arfron

[Minornut59]

Hi everyone.

I am also getting flickering lights exactly as described by somebody earlier on my 59 saloon.
I immediately thought it was the dynamo but have now tried three from my stash of spares and there is absolutely no difference to the flickering. i have a fairly recent battery which stays charged while the car is standing so no drain on it from a short etc. And it stays charged from driving so no going flat at all.


The dynamo seems to be charging just like the other two i have tried; carbon brushes inspected and cleaned with plenty of meat on them; commutator also cleaned....

later clamp type battery terminals, no indication of poor earths as everything works fine but wondering what the cause is....

[bmcecosse]

Why would it be dynamo/battery?? Look to the light switch/connections...and the dip switch connections.

[kennatt]

AS above,how could a dynamo or alternator make the lights flicker,they can effect the brightness,I once had an MGB with lights that increased in intensity depending on how fast the revs were< = regulator fault. Highly likely that you have a bad connection in one of the bullet connectors ,if both are doing it then the earth at the front would be my first check.