110-amp Bosch Alternator Upgrade

[Guest]

thanks Darryl

 

[One Fast MGB]

Chuck:

Just noticed you're in Evansville, IN. I travel to Evansville quite regularly on business. I'll let you know my schedule when I make my next trip. I'll be driving an MG of course. I would really like to get together and swap stories.

Are you a member of the SIR British Motor Car Club host of "The Best Car Show by a Dam Site"?

 

[Dave Russell]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by One Fast MGB:
Piman:
This is why your turn signals will not blink when using brakes and running lights and other equipment. The draw is more than the alternator can produce. The voltage does not change it remains a 12 volt system.
<hr></blockquote>

At the risk of offending someone - everyone - AEROG, When the so called "draw" (load) exceeds the alternator's wattage rating, at a given rpm, the output voltage of the alternator WILL drop. It will NOT remain at 12 volts. I see nothing wrong with Alec's statement except no one seems to be using the same terminology. The blinkers do not work because the voltage has dropped too low to push the necessary current. Eh!
D

 

[Guest]

I agree, if the alternator is forced to exceed its rated output in amps, the voltage will drop. It has no choice, however, up to that point, it will remain at 12v
The output in watts is a result of the current in amps multiplied by the voltage. As the load increases (lowering resistance) the amps increase and the voltage remains constant and the power output increases until the peak rating of the alternator is reached then any increase in amps and power will pull the 12 volts down and things on the car like turn signals will fail to operate and the temperature of the alternator will increase and if it isn't fused ( and I don't think many if any are)eventually thermal runaway in the diodes within the alternator will occur and they will short. Then it will be easy to troubleshoot cause all you have to do is follow the smoke as the windings start to burn.
Bob

 

[Guest]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by One Fast MGB:
Chuck:
Are you a member of the SIR British Motor Car Club host of "The Best Car Show by a Dam Site"?<hr></blockquote>

to be held Sept 18 this year, you bet I am. Check in next time you are hear, and if you happen to stay at the Hampton, ask for Laura, my wife

 

[Dave Russell]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by mrbassman:
:
I agree, if the alternator is forced to exceed its rated output in amps, the voltage will drop. It has no choice, however, up to that point, it will remain at 12v
snip
until the peak rating of the alternator is reached then any increase in amps and power will pull the 12 volts down
Bob<hr></blockquote>

My point exactly. At an engine idle speed of 500 rpm the rated output capability of the alternator is only 28% of it's maximum rating. So if the load at idle is more than 30 amps the alternator voltage will drop & the lights dim, etc. It will however, reach full rated output of 110 amps at around 2000 rpm. Assuming a 2.5/1 pulley ratio. This is what Alec was saying in so many words. Output is not proportional to speed.
D

 

[One Fast MGB]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Chuck Cougill:


to be held Sept 18 this year, you bet I am. Check in next time you are hear, and if you happen to stay at the Hampton, ask for Laura, my wife<hr></blockquote>

Next stay will be at the Hampton. When there I'm at the Hampton or Holiday Inn Conf Center.

 

[One Fast MGB]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Chuck Cougill:
but I was wondering about the ignition lead<hr></blockquote>

The ignition lead from the car is brown w/yellow stripe. Sorry I omitted that. I will correct the article today