Alternator Voltage Drop

[syncrodude]

Hi

I have an Alternator problem , when I measure the voltage on the battery (not leasure) it's about 12.5V (recently been fully charged), when I start the engine with nothing switched on , the voltage drops to 10.5V.
Could a fault in the regulator cause a drop as well as a rise? away from the usual 13-14v charge rate

the Alternator 90A (Bosch type) with brush and regulator pack , brought refurbed about 2 year ago.

Have already been on the Techy downloads bit.

[Red Westie]

Interesting...you would expect an initial voltage drop after supplying 150amps plus to the starter motor for those few cranking seconds. You would assume that voltage drop would recover quickly after the engine has started. What I suspect is happening is the alternater isn't charging at all and the continued 'low voltage' is a result of ongoing current demand from the ignition circuit and any other anchillaries that are switched on (blower,lights etc) clearly the starter battery isn't recieving charge from the alternater.
Martin

[syncrodude]

Thanks , Sort of thought there my not be any output from the Alternator , but wasn't sure, could the regulator be at fault ?

[1664]

What's the ignition light doing? Start the van at night as it maybe glowing too dimly to see in daylight. I doubt it's the alternator packed up totally else the ignition light would be well lit up surely? I had a regulator that played up, I noticed the ignition light dimly lit when I started the van one night; the other sign was when I was driving at night the headlight brightness would jump up and down periodically. The starter battery eventually went totally dead and I replaced the regulator which solved the problem.

[Red Westie]

At under a tenner the brush pack/regulator unit is the most LIKELY cause.
Contact details for the regulator/bush pack supplier:
Vehicle Electrics (Birmingham Ltd) The aftermarket number for MY alternator (yours may be different) was VERG 1009 but they have a list to cross reference your particular aternator number against so you can order the correct item. Mine was £9.70 incl post.
CONTACT VEHICLE ELECTRICS, 166 STOCKFIELD ROAD, ACOCKS GREEN, BIRMINGHAM, B27 6AU. TEL : 0121 706 0688 EMAIL: VEHICLEELECTRICS@AOL.COM

Martin

[syncrodude]

Yes the charge light is on all the time , has gone off a few times , was wondering if is a bad connection on the windings , Thanks very much for your advice folks. Will try the regulator first, if this doesn't work then surgery will be done.