Battery lights for days
 

Okay so here's the situation, I bought my c63 2 years ago, 3 months after I bought it the alternator went bad. I replaced the alternator with an alternator from O'Reillys the car was running great for about a year with that alternator in. Long story short, that one also went bad(not charging the battery properly). I tested it and saw 12.3v going back to the battery which is not right and I also had it confirmed that that alternator was bad. I have since replaced the alternator again(same alternator brand as I have a lifetime warranty on it).I have just replaced the alternator 2 weeks ago and blam sure enough the battery light is back on. I will mention that both the alternator and battery are new.(Battery is 5 months old?) Is it common for this to happen. I don't mind replacing the alternator because its easy but I don't want to have to do it every year haha

I'd go back to an OEM piece. Sure, it'll be more expensive, but you probably won't run into issues every year (or every other week for that matter).

Is it more expensive? Probably, but at the end of the day I'll bet it takes care of your issues.

I understand the warranty on the alternator and if you want to keep going that route it wouldn't be terrible either. You wont have to pay for an alternator and you say its easy for you to do so that works.

As for this being a common issue, haven't seen this before. I won't catch everything here, but this is definitely a rare issue. Which is why I suggest OEM alternator because 99.9% of us are running one.

Where do u recommend getting one from?

Danggg, when to ECS to check at its going to be like $800...

Just keep swapping that alternator under warranty haha

looks like c63's are now being bought up by cheap honda owners. ;)

keep in mind a bad battery will also kill alternators, and on benz the alternator will not always but out max output. the charging algorithms are strange and require the mercedes scan tool to properly test. Frequently the alternator will only be turned to max output on engine decel to help on fuel efficiency. Ultimately if you want your car to avoid breaking down on you using quality parts are paramount.