Battery size

[timber284]

I have a 96 SL1 w/103,000 miles. I replaced the battery 3 years ago with a NAPA size 75 that has 630 CCF and 775 CA. My problem is in the winter I have a very hard time getting the engine to turn over on very cold days. Also, if I step on the brake pedal when the car is off, the dome lights dim. When the car is running at night and I put on the blinker, the dash lights dim every time the blinker goes on. Does my battery have enough power?

Thanks.

[peppermrj]

I would get your battery and alternator tested. They will do this free of charge at a lot of autoparts stores. (autozone, advance, etc.)
My alternator went out at about 110,000. If you don't catch it, it will take the battery with it.

[saturnspeed_12]

well the battery could be bad. see being in winter is the worst time of the year for batteries. but because of that too it could make you believe that thats the problem. like peppermrj suggested have the system tested. at autozone they sometimes cant catch a bad battery or alternator. i know the battery in my moms car is bad yet she had it tested at autozone and it said it was fine. i know the battery is bad still.

as of your battery its is powerful enough. now you can get a digital multimeter and check for how much voltage is getting to the battery while running. it should range from 12.9-14.5 volts. normally it stays closer to 14.5 volts. when the car is off, the battery should have around 12.5 volts. this could be an easy check for you. check your battery on a cold day when its been sitting for a long time and see how many volts it has. if it is below 12 volts its bad. once a battery starts going below 12 volts it can get to the point that it wont start at all.

[drew300]

Check to make sure the battery conections are good. That's a great place to loose power.
I agree the digital meter, but I'll add that when I check the battery volts, engine off, I hope to see at least 12.6, and it should be steady when I turn the headlights on, at about 12.5. If it drops much, and the connections are good, I'd suspect the battery. FYI, an unloaded battery, at 25% charge is about 12.25 V, fully charged is 12.6. To make it easy, I measure thru the cigarette lighter socket first, and then the battery posts if I get a problem thru the socket.