TMunger

I have a 2008 C300 4matic Sport, I recently replaced my battery as the Mercedes Dealer said it was failing. I didn't have them replace it, I bought a Duracell 94R(H7)AGM. I am in Iowa and it gets really cold here, but I've never had to jump my car prior to having my battery replaced. Now every time it's below 10 degrees, I have to have it jumped. The battery, alternator, and everything tests fine.

When I turn insert the key, the dash lights and everything come on, but the radio does not, when I turn the key it doesn't crank it does nothing at all. Is that normal for C300 with a low battery? As soon as I jump it, it starts immediately with no issues. I'm used to a car cranking slowly and not starting with a low battery, but this doesn't do anything at all, but as soon as jumper cables are hooked up it starts.

Do you think it's just a bad battery?

Plutoe

You have the wrong size\quality of battery in the car------simply match the OEM and enjoy the frozen corn!

TMunger

What size should I buy? The dealership told me this size, and this one has 900 CCA. What would you suggest?

insame1

I don't know what your dealer charges but I've found its usually comparable in price to the parts stores. Sound like you have a parasitic draw assuming your battery is spec and your alternator is good.

C230 Sport Coup

Return the battery.