Originally posted by jramshu
You should only run 80% of the the rated load on the alt to prevent damage. A 60 amp alt should be able to handle a cont 48 amps. At least that is how electrical is rated on everything else. For example a 100 amp transformer can not be loaded more then 80% of its rated load or 80 amps. This is done to prevent overheating and damage. The same thing applies to wire. But generally wire is larger than what the maximum load is. I know this because I am a licensed journeyman electrician. Look it up in the National Electric Code. It does not apply to automotives in the code but electricity is electricity. We use deep cycle marine batteries wired in series to run 277 volt lighting and such.
jramshu, you're not comparing apples with apples. the guy was asking about a light that you plug into the lighter. you don't believe that ford and gm figured in to their charging system a little lead way? i don't believe any one thing that you can buy that's made to run off of the lighter is gonna burn your alt. up. he was told he could do it , now you are telling him don't go over 80%. he don't know what 80% of his system is ,but now he still don't know what to do. Tell him it will be ok to run his light some times and he don't have to worry about burning his alt. up.