More powerful Alternator?

[MattP]

I went for a night drive in the B last night and noticed the dim lights. Does anyone sell a more powerful alternator for late-model B's?

 

[Steve]

I think that dim lights are a trademark of the 'B', and that a more powerful alternator will not be the answer. A cheaper alternative would be upgrading your lights to Halogen H4s. I'm considering doing that to mine this spring.

 

[703MGB]

I changed by headlights to Bosch H4 on my B. The difference at night is is very big. For me this was a security issue so I did not hesitated one second.

 

[Guest]

Dimming of the headlight at idle is a common problem withBrit cars but can be fixed by doing the Bosche alternater swap. Just adding better headlights will only make the alternator output problem worse. The origional Lucas was only marginal when new

 

[danmas]

A more powerful alternator may or may not cure your dim lights. It they're dim all the time, it probably won't help, but if they dim when you stop for a traffic light and the engine drops to an idle, it will help. Nevertheless, an upgraded alternator is a very desirable change. For everything you need to know about upgrading your alternator, go to: https://www.s95408591.onlinehome.us/index2.html

If your lights are dim all the time, you need to go through your wiring and clean/replace all the connections, including the lighting switch and the dimmer switch.

Of course, it's also possible that your headlights are bad and just need to be replaced.

If you really want bright lights, go with a set of very high powered lamps and use relays to control them. For more information on this, see https://www.advanceautowire.com (this is my company, so I do have a financial interest, but you're welcome to copy the wiring diagram on my site and make the relay kit yourself. You can buy all the parts from https://www.waytekwire.com/ ).

 

[mgbmedic]

i believe there is a site called "mgb experience" and a section of it called "rick astley's mgb electrical systems" that you may find very helpful. also, if you want to upgrade to a better alternator, www.onefastmgb.com is an excellent conversion that i did and am very happy with. good luck

 

[MattP]

Thanks all, I'll start reviewing websites.

 

[piman]

Hello Matt,
the first thing is to see if there are any problems with your existing system. The easiest way, if you have a meter, is to measure the voltage drop at the headlights themselves. (Light output is very related to applied voltage). If there is a significant drop then you need to find out where that is. (Pay particular attention to the earth).
Until that is verified, a larger alternator will not make any difference and halogen lamps, although brighter, will not give their full output.

When you satisfied that all the voltage available is getting to the light unit then the easiest upgrade is halogen lamps of the same wattage (Assuming you have sealed beam lamps at present). This will not increase the load on the wiring at all but does give much better lighting. Personally, I am not in favour of very high powered lights for road use as they are more dazzling for other road users especially in the rain.
A properly designed relay system will help in giving a slightly higher voltage to the lamps (giving a better light output) and reduce the load on the switchgear.
An alternator upgrade is only necessary if you find that your existing alternator cannot keep up with the load you have. Dimming of the lights at idle is not a issue, in my view, unless you find it affects your indicators significantly.

Alec

 

[MattP]

Thanks Alec. I'll check those things, but I am not too worried about the dipping at idle. I would like a little more light on the run. And don't worry, I could go a long way and still not dazzle anyone. I would also like to add a few accessories, like some driving/fog lights, ect.

That Saturn alternator swap is definately on my list. One word to add. A friend of mine has a '94 Saturn and went through about an AC Delco alternator every 6 mo. He had the Bosch installed, and hasn't had a lick of trouble since. Plus the tail light and stickum foil tip is going to find its way onto the B as well. I have also thought about those bulb based LED arrays since it would pull less on the system.

 

[sockeyedsushi]

Matt, you should consider installing a pair of relays for the lights if you upgrade. This gives more amps to the lights and less through the headlight switch. Saves the switch from premature failure due to high amps and upgrading to GM alternator or the more expensive bosch or saturn alternators. Lots of good sights for explanations. The bulb less led lights are the cats meow for longevity, brightness and power usage. Good luck.