MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Stereo draining electrical system

I recently fitted my 67 mk1 with a car stereo. A pretty basic unit (no amp or cd stackers etc) and have noticed that when driving at night , when the lights are on, the stereo will cut out when sitting at the lights when idle revs drop down low ?
I can also see the panel lights dimming in time with the beat. Seems like it is putting an awful strain on the electrical system. Am I doing any harm here.

Craig
Craig Williams

your stereo is probably fine, just telling you that your electrical/charging system is very marginal. Check your battery, cables, grounds, bullet connectors etc. ,or most likely your alternator is weak.good luck.
Joaquin

Craig,
If you have a MK 1 then you probably have a generator, not am alternator. Generators typically put out very low amperage at idle, switching over to an alternator will be a big plus to your electrical system. There are many sites you can visit on the web for changing over instructions.
Steve
Steve Brooks

The dynamo fitted to mk1 cars is pretty poor even in tip top condition and at a few thousand revs. Back when mine was still on the car, I could have any two out of lights, wipers and stereo but not all 3... lost ignition after about 10 minutes driving with all systems on, as battery voltage had dropped enough (yes, weak battery at the time) not to be able to drive the coil properly.

Bosch 55A conversion seems like the logical step as it's just as easy as changing to a lucas unit.

hth,
--
Olly
Oliver Stephenson

If your lights are dimming with the beat, your stereo is pulling some heavy amps--not uncommon for a basic unit to draw 100+ watts/channel. Another thought is that the vibrations from the bass are affecting some less than perfect electrical connections in your car. Plus, it takes more current to produce that thumping base some folks like. Upgrade your generator to a high output alternator and get a heavy duty battery.
R. L Carleen

I'm with Oliver's suggestion to first swap to a Bosch 55 amp alternator. The original Lucas ACR alternator can barely keep up with the headlights, wipers and heater blower at the same time.

After that, inquire about installing a set of bass capacitors into the speaker wiring. These things are
about the size of a soup can and work to even out the sudden momentary power drops that some
extra heavy bass notes inflicts. Your local auto stereo installer should know about matching these
to your exact system.

...of course, you can always tune down the stereo volume a bit and instead listen to the "rap" that is
bellowing from your B's exhaust tip...
Daniel Wong

Craig,
I had a lot of problems with the generator when I got my 66B. After doing a lot of work cleaning all the electrical contacts I could find, getting the regulator checked and reset by an auto electrician, and setting the idle to just over 1000rpm, I havn't had any problems for a couple of years now.

so... have you had the generator and regulator checked out?
P R Akers

This thread was discussed between 15/06/2003 and 16/06/2003

MG MGB Technical index

This thread is from the archive. The Live MG MGB Technical BBS is active now.