Dallasfool

replaced my battery in my 2004 on 03/17/19, went to start it on 03/23/19 nothing ? couldn't even use key fob to unlock the door, had use jump box to get it stared, is this a alternator going bad? ran find on the 17TH but hasn't been started again till the 23rd? apricate your help!

C5 Diag

You might have a “parasitic drain” on your battery...battery most likely went dead in those 6 days it was sitting. A jump bought it back to life...can be a few things like an interior light remaining on or even bad diodes in your alternator to name a few... there are a few other areas of concern in the C5 that are documented here on the forum...don’t know if you are mechanically inclined or own a multimeter and know how to use the amperage function and if your DVOM has a mV scale that’s even better

but that’s all you need to troubleshoot this...just takes a little patience to nail it down...in order to save time and typing I believe Bill Curlee has a sticky up top concerning this issue...also there are MANY YouTube videos on how to perform the testing...pulling fuses are the worst to isolate the problem and voltage drop testing of the fuses being the BEST...my favorite too !!

GCG

Troubleshooting is essential and you probably have something draining your battery, as mentioned above.

Don't blindly replace your alternator: there are plenty of horror stories!... In any case, DON'T turn in your old alternator as core.

Take a look at this post for an in-depth analysis of the C5 alternator.

What makes this alternator so peculiar is that it is excited when its regulator receives a turn on signal of 10v at limited current provided by the PCM through the L wire. Not all regulators accept the turn on signal provided by the C5 PCM.

Another distinctive attribute described by Lionelhutz in this post:

For a potential rebuilt route, take a look at this post. It has info on the right regulators for both, 97-01 and 02-04. The price is around $30.

This other post has detailed info on the rebuild procedure and links to get the other parts.

Grandpa1

Have the new battery checked for a dead cell. It happens.

Dallasfool

started right up yesterday,3/24/19,

BigGun

Check that the connections on the new battery are tight. You should not be able to turn them by hand. From almost totally dead to started right up is a bad connection.

Dallasfool

I checked connection again 3/26/19, all tight and clean, had battery tested came back good, the testing machine at one time said, engine noise, but everything was turned off,

Tested good

Dallasfool

Have appt with Chevrolet 3/27/19 have them check it out

BigGun

Going to the stealership is never a good idea. Unless you are extremely lucky n one there will know anything about a C5. Are you still having the same problem?

Dallasfool

the dealership couldn't find anything wrong, wasn't charged for anything, I guess I should keep a trickle charger on it, just didn't make any sense to me, why brand new battery would go dead in 6 days after purchase, but I do appreciate everyone's input!

It's warming up! Drive it a little more!

C5 Diag

Dude, your battery should NOT be dead in 6 days PERIOD...end of story...take it to a good shop in your area...how about Clarksville Automotive Engine Repair...see Lou !!

Bill Curlee

My car can sit for an easy 30 days and the battery will still crank the engine. You should have 20 milliamps for sleep current draw when the car is off and resting.

You SHOULD also have a battery with the CORRECT reserve capacity! If I remember correctly, it 120 RC. Its tough to find a 120 RC battery that doesn't cost an arm and a leg. 110 RC will work fine.

Bill

Bill Curlee

Invest in a GOOD battery tender. I use the CTEK Battery Tender.
Its an intelligent charger that wont cook the battery if you keep the car on a tender over a long period of time.. They have several different chargers/tenders with a whole host of different features.
Check them out.. I have had excellent results with the two that I own. They now have a attachment that you can add that will allow you to see the condition of you battery using an APP on your phone.

NOTE.. You can modify the battery tray on you car to allow it to accept a longer battery. I did that to my C6 Grand sport I will do it to my 02 Z when I install my next battery.

Bill