[W126 Coupe] 1982 380SEC - started but won't stay charged

[Dan Landiss]

on 6/18/2009 9:23 PM Mark Foster wrote:

> The battery seems fine

> as I had it on charge for a few days before attempting this. So, I am

> guessing the next natural trouble shooting progression would be the

> alternator? 

>   


I'd think that if you had the battery on a charger for a couple of days 
it could start the car several times and run it for many hours. I'd 
suspect the battery first.

You can do a rough test on the alternator by checking the charging 
voltage while it is running over 1500 - 2000 RPM. Look for over 14 
volts, maybe just under 14 if the engine compartment is quite hot.

-- 

"I think it would be a good idea."  --Mahatma Gandhi, when asked what he thought of Western civilization